taxonID	type	format	identifier	references	title	description	created	creator	contributor	publisher	audience	source	license	rightsHolder	datasetID
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913561/files/figure.png	https://doi.org/10.5281/zenodo.10913561	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD6FFE95AE48B3CFD3223B0.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913577/files/figure.png	https://doi.org/10.5281/zenodo.10913577	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD7FFEA5AFB8DFBFBE327D1.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD4FFEB5A1C8B97FE8924ED.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD5FFEB59DC8CD9FA692094.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD3FFED59D68E7FFC472324.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD3FFED59D68E7FFC472324.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913561/files/figure.png	https://doi.org/10.5281/zenodo.10913561	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD3FFED59D68E7FFC472324.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD3FFED59BA88A6FDD1224D.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913565/files/figure.png	https://doi.org/10.5281/zenodo.10913565	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	Figure 3. Poracanthodid and ischnacanthid acanthodian scales from Upper Silurian levels of the Birch Creek II section. A–E,?F,?G. Gomphonchoporus hoppei: A. UCR 949-1 (level 567.3') in crown view (from Supplement 1, fig. 24); B. UCR 944-11 (level 527.25') in laterocrown view; C, D. UCR 5439-2 (level 549') in anterocrown and laterocrown views; E. UCR 5439-3 (level 549') in basal view; F. UCR 5439-7 (level 549') in crown view; G. UCR 5439-1 (level 549') in anterocrown view. H–J. Zemlyacanthus menneri: UCR 10815-1, 2, 3 (level 556.5'), in crown views (from Supplement 1, fig. 22). M–P. Trundlelepis cervicostulata: K, L. UCR 10768-4 (level 518.3') in anterior and lateral views; M. UCR 944-17 (level 527.25') in crown view; N. UCR 944-3 (level 527.25') in crown view; O. UCR 944-23 (level 527.25'), vertical longitudinal thin section; P. UCR 944-22 (level 527.25'), horizontal thin section through crown. Q, R. Poracanthodidae gen., sp. indet. sensory line scale UCR 930-3 (level 395') in crown and posterior views. S-V. Gomphonchus sandelensis: S, T. UCR 10746-11 (level 430.5') in crown and lateral views; U,V. UCR 930-7 (level 395') in antero- and posterocrown views. W–Z. Gomphonchus mediocostatus: W. UCR 944-6 (level 527.25') in crown view; X. UCR 944-16 (level 527.25') in crown view; Y. UCR 942-1 (level 526') in crown view (from Supplement 1, fig. 20); Z. UCR 944-19 (level 527.25') in laterocrown view. Abbreviations: cgz=crown growth zones; dt=dentine tubules; h=hyphal borings; vc=vertical canals. Scale bars=0.1 mm, anterior of scale	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD3FFED59BA88A6FDD1224D.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFD0FFEF5A008C49FDCC2079.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF159D58DF6FBC626F8.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913563/files/figure.png	https://doi.org/10.5281/zenodo.10913563	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 2. Poracanthodid acanthodian scales from Upper Silurian levels of the Birch Creek II section, SEM images. A–G. Poracanthodes punctatus: A, B. UCR 930-2 (level 395') in lateral and posterobasal views; C. UCR 930-6 (level 395') in posterobasal view; D, E. UCR 930-5 (level 395') in crown and posterocrown views; F, G. UCR 930-1 (level 395') in lateral and basal views. H–P,?Q–V. Poracanthodes canadensis: H, I. UCR 930-4 (level 395') in crown view; J, K. UCR 10746-6 (level 430.5') in crown view plus closeup of crown pores; L–N. UCR 10750-6 (level 456.5') in anterior and crown views, and closeup of pores near hyphal borings; O. UCR10746-5 (level 430.5') in laterocrown view; P. UCR 540-1 (level 510’) in crown view (from Supplement 1, fig. 17); Q–S. UCR 10768-3 (level 518.3') in crown, anterocrown views, and closeup of posterior crown surface; T. UCR 930-8 (level 395'), horizontal thin section through crown; U,V. UCR 10746-12 (level 430.5'), vertical thin section through anterior half of crown; W–BB. Radioporacanthodes porosus: W, X. UCR 10750-7 (level 456.5') in crown and anterocrown views; Y, Z. UCR 10746-4 (level 430.5') in anterocrown and lateral views; AA. UCR 10746-9 (level 430.5') in crown view; BB. UCR 10750-11 (level 456.5'), horizontal thin section through crown, showing two radial pore canals, viewed with Nomarski optics. CC–EE. Radioporacanthodes scheii: CC. UCR 10750-5 (level 456.5') in crown view; DD, EE. UCR 10750- 1 (level 456.5') in crown view plus closeup of pores and hyphal borings. Abbreviations: arc=arcade canals; b=scale base; c=scale crown; h=hyphal borings; n=neck; p=pore; pc=pore canal; pco=pore canal opening under posterior crown; pr=pore canal opening row on crown surface; rc=radial canal. Scale bars=0.1 mm, anterior of scale is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913571/files/figure.png	https://doi.org/10.5281/zenodo.10913571	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913577/files/figure.png	https://doi.org/10.5281/zenodo.10913577	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35986899AFA8D264B.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913571/files/figure.png	https://doi.org/10.5281/zenodo.10913571	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35986899AFA8D264B.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35986899AFA8D264B.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913571/files/figure.png	https://doi.org/10.5281/zenodo.10913571	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 6. Chondrichthyan and stem osteichthyan scales from the uppermost Silurian of the Birch Creek II section; A, C–G, light microscope images of whitened specimens; B, ESEM image. A-C. Ellesmereia schultzei. A, scale UCR 10746- 44 (level 430.5’) in crown view (from Suppl. 1, fig. 5); B, UCR 10746-28 (level 430.5’) in anterolateral-crown view; C, scale UCR10746-45 (level 430.5’ in crown and lateral views (from Suppl. 1, fig. 4). D. Polymerolepis sp. scale UCR 10752-1 (level 458.67’) in crown view (from Suppl. 1, fig. 11). E-G. Lophosteus sp. cf. L. superbus. E, dermal bone fragment 10754-1 (level 468’) in external view (from Suppl. 1, fig. 12); F, G, tubercles UCR951-1, 2 (level 457’) in crown views (from Suppl. 1, fig. 10). Scale bars=0.25 mm, anterior of scale is up or to left, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCAFFF4599F8F1EFAE224B3.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913561/files/figure.png	https://doi.org/10.5281/zenodo.10913561	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	Figure 1. Birch Creek II section, central Roberts Mountains, Nevada. A. locality map, topographic map showing locations of sections BC II, BC III, WC I, WC IV after Murphy (2016, appendix 1). B. stratigraphic column through the uppermost Silurian– lowermost Devonian (after Klapper and Murphy 1975, fig. 5; scale on left is in feet; X denotes their proposed Silurian–Devo- nian boundary at approx. 567’=172.8 m level); to the right, stratigraphically significant conodont ranges in red, graptolites in blue (see Murphy 2016, fig. 2).	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFCBFFF75AA08F5FFE982531.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC9FFF7584C8C56FEFA21CB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC9FFF758478F72FA8523BB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC9FFF758478F72FA8523BB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC9FFF758478F72FA8523BB.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913577/files/figure.png	https://doi.org/10.5281/zenodo.10913577	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC6FFF859B58D63FB182284.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC6FFF859B58D63FB182284.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC6FFF859B58D63FB182284.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913577/files/figure.png	https://doi.org/10.5281/zenodo.10913577	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	Figure 9. Paleogeographic reconstruction for the late Silurian, base map from Scotese (2014, map 73), showing possible vertebrate dispersal route from the Baltic to the circum-Arctic and thence south to western Laurentia.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC7FFFA5AB28A0FFD4B2308.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC7FFFA5AB28A0FFD4B2308.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC4FFFA5D438B70FA6B2329.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913575/files/figure.png	https://doi.org/10.5281/zenodo.10913575	Figure 8. A–K. Scales of thelodont Barlowodus sp. cf. B. floralis from the uppermost Silurian of the Birch Creek II section, all level 430.5'. A, UCR 10746-31 in baso-lateral view; B, UCR 10746-35 in crown view; C, UCR 10746-36 in crown view; D, UCR 10746-34 in crown view; E, UCR 10746-42 in crown view; F, UCR 10746-29 in crown view; G, UCR 10746-24 in crown view; H, UCR 10746-38 in crown view; I, UCR 10746-23 in crown view; J, K, UCR 10746-14, in crown view, and close up of dorsal mid-crown showing ultrasculpture and taphonomic effects. Scale bars=0.2 mm; anterior to left except A, D, G, I. See Table 1 for meterage.	Figure 8. A–K. Scales of thelodont Barlowodus sp. cf. B. floralis from the uppermost Silurian of the Birch Creek II section, all level 430.5'. A, UCR 10746-31 in baso-lateral view; B, UCR 10746-35 in crown view; C, UCR 10746-36 in crown view; D, UCR 10746-34 in crown view; E, UCR 10746-42 in crown view; F, UCR 10746-29 in crown view; G, UCR 10746-24 in crown view; H, UCR 10746-38 in crown view; I, UCR 10746-23 in crown view; J, K, UCR 10746-14, in crown view, and close up of dorsal mid-crown showing ultrasculpture and taphonomic effects. Scale bars=0.2 mm; anterior to left except A, D, G, I. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913567/files/figure.png	https://doi.org/10.5281/zenodo.10913567	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 4. Nostovicina and Nostolepis sp. acanthodian scales from the Siluro-Devonian boundary levels of the Birch Creek II section. A. Nostovicina sp. cf. N. elegans: UCR 10755-1 (level 470.2’) in crown view (from Supplement 1, fig. 13). B–D, J. Nostovicina laticristata: B. UCR 10768-10 (level 518.3') in crown view; C, D. UCR 10768-6 (level 518.3') in anterocrown and crown views; J. UCR 10768-11 (level 518.3') horizontal thin section through crown. E–I, K, L. Nostovicina sp. cf. N. guangxiensis; E. UCR 5443-1 (level 562.6') in anterocrown view; F, G. UCR 5443-3 (level 562.6') in crown and lateral views; H. UCR 5443-4 (level 562.6') in posterocrown view; I. UCR 5443-6 (level 562.6') in crown view; K, L. UCR 5443-7 (level 562.6') vertical transverse section, magnified view of crown structure in L. M–P. Nostovicina sp. cf. N. lacrima: M. UCR 5439-8 in lateral view; N. UCR 5439-6 in posterior view; O. UCR 5439-4 (level 549') in lateral view; P. UCR 10768-1 (level 518.3') in anterior view. Q–T. Nostolepis matukhini: Q, R. UCR 5443-2 (level 562.6') in crown and laterocrown views; S, T. UCR 5443-5 (level 562.6') in crown and anterocrown views. Abbreviations: cgz=crown growth zones; h=hyphal borings; Sf=Sharpey’s fiber bundles. Scale bars=0.1 mm, anterior of scale is to right or up, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913569/files/figure.png	https://doi.org/10.5281/zenodo.10913569	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	Figure 5. Funicristata nevadaensis n. gen. n. sp. from the uppermost Silurian of the Birch Creek II section. A–C. UCR 10750-3 (level 456.5') in crown views and magnified view of the crown ridges; D, E. UCR 10750-2 (level 456.5') in crown and lateral views; F, G. UCR 10746-10 (level 430.5') in anterocrown and crown views; H, I. UCR 10746-8 (level 430.5') in anterocrown and laterocrown views; J, K. UCR 10750-10 (level 456.5') vertical longitudinal section; L. UCR 10750-12 (level 456.5') horizontal section through crown. Abbreviations: c=canal; en=enameloid; h=hyphal boring; po=pore openings. Scale bars=0.1 mm in A, B, D–L, 0.01 mm in C; anterior is to left or down, otherwise arrows point to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	http://purl.org/dc/dcmitype/StillImage	image/png	https://zenodo.org/record/10913573/files/figure.png	https://doi.org/10.5281/zenodo.10913573	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	Figure 7. Thelodont scales from the uppermost Silurian of the Birch Creek II section, all level 430.5' except B, C, G, K, L, P, Q. A. Trimerolepis sp. cf. T. tricava. UCR 10746-43 in crown view. B. Trimerolepis sp. AMF97876 (Parkes 1995, fig. 22.19, 20) from level 503’, base view. C.?Lanarkia sp. UCR 944-20 (level 527.25’) in lateral view. D.?Turinia sp. UCR10746-19, showing taphonomic effects and ultrasculpture, in crown view. E-J. Nikolivia spp. E. UCR 10746-13 with cell pattern on surface in crown view; F, UCR 10746-20 in crown view; G, AMF97875 (Parkes 1995, fig. 22.17, 18) from level 402' with possible bite marks, in crown view; H, UCR 10746-27 in ventral basal view; I, UCR 10746-25 showing taphonomic effects in crown view; J, Nikolivia sp. cf. N. auriculata, UCR 10746-18 in crown view. K, L. Apalolepis sp. AMF97872 (level 503’) (Parkes 2005, fig. 22.11, 12), crown and basal views. M-O. Talivalia sp. cf. T. elongata. M, UCR 10746-17 in crown view; N, UCR 10746-37 in crown view; O, UCR 10746-21 in lateral view. P-S. Barlowodus sp. cf. B. tridens. P,Q, AMF97874 (level 875’) in crown and basal views (Parkes 2005, fig. 22.15, 16). R, S, UCR 944-21 (level 527.25') in laterocrown view, closeup in S showing striated ultrasculpture. Scale bars=0.2 mm; anterior to left or top, otherwise arrow points to anterior. See Table 1 for meterage.	2023-06-06	Burrow, Carole Jan;Murphy, Michael;Turner, Susan		Zenodo	biologists	Burrow, Carole Jan;Murphy, Michael;Turner, Susan			
