taxonID	type	description	language	source
B21CD55BFFD8FFE6599A8AB2FF2A2439.taxon	type_taxon	Type species — Poracanthodes punctatus Brotzen, 1934	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	description	(FIG. 2 A – 2 G; TABLE 1; SUPPL. 1, FIGS. 1?, 2 - 18)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	description	“ P. punctatus ... scales ... figured ... are from P. canadensis ” in part; Burrow 2003 a, 490.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	materials_examined	Type material — The syntype scales MB. f. 11979 a and b figured by Brotzen (1934, pl. 3 figs. 1, 8), were from an erratic limestone boulder Bey. 36 in northern Germany. Gross (1947, 1971) used Brotzen’s material in his redescription of P. punctatus and other taxa, and captioned scale MB. f. 11979 b (Gross 1947, text-fig. 11 A) as the holotype, now designated as the lectotype by Burrow & Märss (2022). Referred specimens — Poracanthodes punctatus scales are found at most levels from 395 ’ – 513 ’ (120.4 – 156.4 m) in the BC II section (Table 1), and include UCR 930 - 1, - 2, - 5, - 6 (all level 395 ’ = 120.4 m), and AMF 97948, 97950 (level 402 ’ = 122.5 m), figured by Parkes (1995, fig. 32.5, 32.6, 32.9, 32.10): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD8FFE859D28B05FDC9260D.taxon	description	Description — These scales are the most common form in the lower levels of the section. They have a relatively smooth crown with a shallow sulcus leading back from the anteromedian corner, and close-set evenly spaced pores along the margin between growth zones paralleling the posterolateral edges of the crown (Fig. 2 A, 2 D – 2 F). Ridges are absent or only very weakly developed along the anterior margin of the crown (Fig. 2 A). Each side of the undersurface of the posterior crown on most scales has three large openings to the pore canal system at the crown – neck junction (Fig. 2 A – 2 C, 2 F, 2 G). The area of the neck below the openings has strong buttresses aligned with the openings, separated by deep grooves. A strong rim separates the neck and base, which is convex and of a similar height to the neck, with the deepest area usually forward of the centre of the scale and with the front of the base protruding in front of the anterior edge of the crown. Despite the poor preservation and extensive hyphal borings through the scales, the scale crowns are observed to have the pore canal layout typical of Poracanthodes punctatus, with c. six radial pore canals interconnected by arcade canals, from which short canals rise up to the pore openings aligned along the growth zones on the crown. Comparison — These scales conform to the morphology of the lectotype scale (Brotzen 1934, pl. 3.1; see Burrow and Märss 2022) from an earliest Devonian (Lochkovian) erratic boulder (Bey. 36) of the north German lowlands. Gross (1971) noted that the scales from this level were morphologically the same as those from the Beyrichienkalk and the Kaugatuma and Ohesaare Beds (Přidolí, Upper Silurian) of the Baltic countries, but the latter differed in having many more radial canals (4 – 10) in their internal pore canal system, and should probably be assigned to a new species – to date, this has not been done. The BC II scales resemble the older forms, but with no morphological features to distinguish them (other than the number of large canal openings under the posterior crown), we prefer to keep the present nomenclature, whilst recognizing that the number of radial canals decreases between the upper Přidolí and the lowermost Devonian. Poracanthodes punctatus is a zonal vertebrate for the Baltic in the upper Přidolí (Märss et al. 1995; Märss and Mannik 2013), although its range is greater in shallow shelf than in deep shelf environments (Märss 1997, fig. 6). As well as the Baltic region and the north German lowlands, P. punctatus is recorded from the Přidolí of the Barlow Inlet Formation (Märss et al. 1998) and Cape Phillips Formation (Burrow et al. 1999) in the Arctic Canadian Archipelago, upper Přidolí erratics of the northern Netherlands (Vergoossen 1999 a), uppermost Přidolí and lowermost Lochkovian of the Welsh Borderlands (Vergoossen 2000, table 1, Turner et al. 2017), Ludlow – Přidolí of October Revolution Island and Komsomolets Island and Lochkovian – Pragian of Severnaya Zemlya (Valiukevičius 2003 a), and the S – D boundary beds in the Eastport Formation, Maine (Turner and Burrow 2018). It has also been recorded from another area in the Roberts Mountains Formation, in the Přidolí of Pete Hanson Creek (Burrow 2003 a).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	description	(FIG. 2 H – 2 P, T – V? 2 Q – S; TABLE 1; SUPPL. 1, FIGS. 2 - 19)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	diagnosis	Diagnosis — see Burrow et al. (1999).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	materials_examined	Type material — Holotype scale GSC 116340; Paratype scales: flank scale GSC 116339, transitional scale GSC 116343; Locality C- 11460, Marshall Peninsula, Cornwallis Island, arctic Canada; Cape Phillips Formation (Late Silurian, Ludlow or Přidolí). Referred specimens — Poracanthodes canadensis scales are found at most levels from 395 ′ – 518.3 ′ (120.4 - 156.8 m) in the BC II section (Table 1), and include UCR 10750 - 6 (456.5 ’ = 139.1 m), UCR 10746 - 5, - 6 (430.5 ’ = 131.2 m), UCR 930 - 4 (395 ’ = 120.4 m), possibly UCR 10768 - 3 (518.3 ’ = 158 m), and thin sections UCR 930 - 8 and - 9 (395 ’ = 120.4 m); also AMF 97947 (level 513 ’ = 156.4 m) and AMF 97951 (level 402 ’ = 122.5 m), figured by Parkes (1995, fig. 32.1, 32.2, 32.9, 32.10): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	description	Description — The scales have 6 – 16 short, sharp, mostly even-spaced ridges running back from the anterior edge of the crown. The rest of the crown is relatively smooth, with close-set evenly spaced pores along the margin between growth zones paralleling the zig-zagging posterolateral edges of the crown (Fig. 2 H – 2 P). Unfortunately, the posterior area of most scale crowns has broken off, and the zig-zag orientation of the outer rows of pores, characteristic of P. canadensis, is only rarely preserved (Fig. 2 P). Each side of the undersurface of the posterior crown on most scales has three or four large openings to the pore canal system at the crown-neck junction. The neck and base morphology is comparable with that of P. punctatus. One of the scales figured (Fig. 2 Q – S) could possibly be from P. punctatus, as the anterior crown ridges are only weakly developed (or alternatively, worn down) and there is a slight anterior median sulcus. Despite the poor preservation and extensive borings through the scales, thin sectioning shows that the scales have the pore canal layout typical of Poracanthodes canadensis, with six or eight radial pore system canals interconnected by v-shaped arcade canals, from which short canals rise up to the pore openings aligned along the growth zones on the crown (Fig. 2 T – V).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE859ED8957FB6825AA.taxon	discussion	Comparison — Scales of P. canadensis can be distinguished from other poracanthodid taxa by their multiple short sharp ridges along the anterior rim of the crown and the alignment of pore openings parallel with the posterolateral edges of the crown, forming a zigzag pattern paralleling the jagged denticulations in younger zones. The taxon is only recorded elsewhere from the Přidolí of the Barlow Inlet Formation (Märss et al. 1998) and Cape Phillips Formation, Arctic Canadian Archipelago (Burrow et al. 1999), and now from Nevada.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE85AF58AB5FA6B243D.taxon	type_taxon	Type species — Poracanthodes porosus Brotzen, 1934.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE95AE48B3CFD3223B0.taxon	description	(Fig. 2 W – AA,? 2 BB; Table 1; Suppl. 1, figs. 3 – 13)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE95AE48B3CFD3223B0.taxon	diagnosis	Diagnosis — see Vergoossen (1999 a).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE95AE48B3CFD3223B0.taxon	materials_examined	Type material — The holotype scale MB. f. 11989 a (Brotzen 1934, pl. 3 fig. 2, Gross 1947, text-fig. 11 M) is from an erratic limestone boulder in northern Germany (Early Devonian, Lochkovian). Referred specimens — Scales probably occur at most levels from 395.01 ′ – 491.3 ’ = M 48 A (120.4 – 149.7 m), and possibly up to 510.90 ′ (155.7 m) in the BC II section (Table 1), and include UCR 10750 - 7 (456.5 ’ = 139.1 m), UCR 10746 - 3, - 4, - 9 (430.5 ’ = 131.2 m) and thin section UCR 10750 - 11 (456.5 ’ = 139.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD6FFE95AE48B3CFD3223B0.taxon	description	Description — The most common scale form of this species in the BC II section has a flat relatively smooth crown with a shallow median sulcus and up to six low weak ridges on the anterior margin (Fig. 2 W – Y). These scales are smaller on average than those of Poracanthodes, being less than 0.3 mm wide and long. Pore openings in the posterior half of the crown surface are round, or short slits, and arranged in two or four subparallel rows leading back from the widest area of the crown to its posterolateral edges, although on most scales the posterior end of the crown has broken off (Fig. 2 Y, BB). A horizontal thin section of the crown of one of the smaller scales (Fig. 2 AA) shows two radial canals of the pore canal system, without any interconnecting arcade canals. The posterior crown is missing on one scale (Fig. 2 BB), but the anterior crown and exposed canals in the posterior fracture surface indicate that this is also probably R. porosus. Comparison — Scales of Radioporacanthodes porosus sensu stricto (i. e. conforming to the type illustrated by Brotzen 1934, pl. 3.2) can be distinguished morphologically from other poracanthodid taxa by their median sulcus on the anterior rim of the crown, their lack of, or only weakly developed, anterior crown ridges, and the subparallel to radial alignment of large pores or small slits on the posterior half of the crown. The taxon is widely distributed, being recorded in the Lower Devonian erratic boulders of the north German lowlands, Přidolí – Emsian of the Baltic countries (Valiukevičius 2000), upper Přidolí – lowermost Lochkovian of the Welsh Borderlands (Vergoossen 2000, pl. 3.28, 3.29, Turner et al. 2017), Lochkovian Cookeys Plains Formation, New South Wales, Australia (Burrow 2003 b), Lochkovian Borschchov and Ivane Regional Stages, Ukraine (Plax 2011) and possibly the lowermost Devonian of Tewo and Zoige counties, West Qinling Mountains, China (Wang et al. 1998: Poracanthodes cf. P. porosus and Poracanthodes zoigensis). The scale varieties with much more ornate crowns from the Baltic and central Urals that Märss (1986, 1997) and Valiukevičius (1998) assigned to Poracanthodes porosus have subsequently been reassigned to Poracanthodes? lehmani Vergoossen (1999 b), and Radioporacanthodes biblicus (Lehman 1937) by Vergoossen (2002 a); neither of these species are found in the BC II section.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFE95AFD8D48FA222260.taxon	type_taxon	Type species — Gomphodus hoppei GROSS, 1947.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	description	(FIG. 2 CC – EE; TABLE 1; SUPPL. 1, FIGS. 2, 3, 5, 9 – 13)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	diagnosis	Diagnosis — see Burrow (2013).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	materials_examined	Type material — The holotype is fin spine CMN 55213, in a block with other fin spines, jaw fragments and scales considered to be conspecific; from the northwest side of Irene Bay, Ellesmere Island, arctic Canada, Devon Island Formation (Přidolí? or early Lochkovian). Referred specimens — Rare scales recognized at levels 395 ’ (120.4 m), 424.9 ’ (129.5 m), 430.5 ’ (131.2 m), 456.5 ′ – 471 ′ (139.1 - 143.6 m) in the BC II section, including UCR 10750 - 1, - 5 (level 456.5 ’ = 139.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFE959F68C8BFBA8220F.taxon	description	Description — These scales are characterised by regularly spaced short sharp ridges along the anterior edge of the crown, without a median sulcus. Pore openings are relatively small, with a maximum of six subparallel rows running back along the posterior half of the crown (Fig. 2 CC-EE). The undersurface of the posterior crown has the large canal openings characteristic of this family (not illustrated). The small pores on the crown surface are not always visible with a light microscope, and some scale varieties lack pores. Comparison — Burrow (2013) reassigned this species from “ Ischnacanthus? ” to Radioporacanthodes based on presence of a pore canal system in the crown of most scales, while also recognising that some variants lack a pore canal system. The BC II scales show some similarity with those of Poracanthodes canadensis in having many short ridges along the anterior edge of the crown, but differ in having a few small pores in subparallel rows on the posterior crown, rather than rows of many pores paralleling the posterolateral crown edges. As noted above, some scales also lack a pore canal system, making it difficult to distinguish these from scales of Gomphonchus volborthi (Rohon, 1893), a species resurrected by Vergoossen (1999 c), and Gomphonchus sandelensis scales with weakly developed anterior crown ridges. G. volborthi usually has rounded weak anterior ridges, and is probably restricted to older strata (Vergoossen 1999 c). The scales differ from the Gomphonchoporus hoppei variants, which lack a pore canal system in having a smoothly curving anterior crown margin rather than a relatively sharp mid-margin angle (Vergoossen 1999 a, figs. 41 – 45, 55, 56).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFEA5AFB8DFBFBE327D1.taxon	description	(FIG. 3 A – 3 E,? 3 F,? 3 G; TABLE 1; SUPPL. 1, FIGS. 12?, 18 – 25)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFEA5AFB8DFBFBE327D1.taxon	diagnosis	Diagnosis — see Vergoossen (1999 a). Type material — Holotype: scale MB. f. 449 (Gross 1947, pl. 24 fig. 7); from the Beyrichienkalk, northern Germany; exact collection locality unknown (Late Silurian, Přidolí?). Referred specimens — Scales at most levels from 513 ′ – 591.5 ’ (156.4 - 180.3 m), and possibly level 468 ’ (142.6 m) in the BC II section, including UCR 944 - 11 (527.25 ’ = 160.7 m), UCR 5439 - 2, 3, UCR 5439 - 1, 7? (level 549 ’ = 167.3 m); and AMF 97959, 97960 (level 513 ’ = 156.4 m), figured by Parkes (1995, fig. 33.5 – 33.8, captioned as Acanthodian 1 and Poracanthodes sp.): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFEA5AFB8DFBFBE327D1.taxon	discussion	Remarks — As discussed by Vergoossen (1999 a), the type scales described and figured by Gross (1947, 1971) were abraded, with delicate structures missing, in particular, the lateral areas of the posterior crown. For this reason, Vergoossen (1999 a) nominated well-preserved scales from a northern Netherlands erratic as neotype and paratypes. However, the type specimen is still reposited in the MB. f collection so those allocations are not valid. Being better preserved than the type scales, those from the Netherlands erratic are more useful for comparative purposes.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD7FFEA5AFB8DFBFBE327D1.taxon	description	Description — Scales from BC II are comparable with the scale nominated by Vergoossen as a neotype (1999 a, pl. 4.42 – 4.44) and have numerous ridges leading back from the anterior margin (Fig. 3 A), whereas others have a shallow median sulcus running back from the anterior edge of the crown to the level of the lateral corners, and only a few short low ridges running back from the anterior margin (Figs. 3 A – 3 D,? 3 F,? 3 G). The straight anterior edges of the crown meet at an acute angle. The posterior crown is formed of appositional growth zones, expressed on the surface as long slits paralleling the straight posterolateral edges of the crown, or with more anterior growth zones appearing to overlap the growth zone behind (Fig. 3 A). Few of the BC II scales have the posterolateral edges preserved, but at least one scale (Parkes 1995, fig. 33.5, 33.6) has the close-set denticulations that are visible on the well-preserved scales figured by Vergoossen (1999 a). The scale neck is concave all round, and of comparable height to the base, with a marked rim separating neck and base. A strong median ridge rises from the posterior base towards the lower surface of the crown (Fig. 3 A, B), and the undersurface of the posterior crown (Fig. 3 E) shows the wide canal openings that typify poracanthodid scales. Some scales with relatively long aligned slits on the posterior crown surface (Fig. 3 F, G) are tentatively assigned to the species. Comparison — Some scales approach the morphology of small (fin?) scales from Zemlyacanthus menneri (Valiukevičius 1992, pl. 10.6 – 10.8), but only have straight slits and pore openings in the posterior area of the crown, rather than zigzag slits extending close to the anterior margin that characterize Z. menneri, and so are assigned on this basis to G. hoppei.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD4FFEA5ADF896AFBFE24CF.taxon	type_taxon	Type species — Poracanthodes menneri Valiukevičius, 1992.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD4FFEA5ADF896AFBFE24CF.taxon	discussion	Remarks — The pore canal system in Z. menneri scales is of the punctatiform type sensu Vergoossen (1997), with both arcade and radial pore canals (Valiukevičius 1992), but the scales differ from those of Poracanthodes and Radioporacanthodes in having only appositional growth zones forming the posterior crown, and canals opening out on the surface in long slits parallel to the denticulated posterolateral edges. In scales of Poracanthodes the canals open out through rows of small pores with the same alignment, and in Radioporacanthodes through slits or large pores in radiating rows above the radial canals. Gomphonchoporus scales with pore canal systems are porosiform. For these reasons, and because it is the only poracanthodid species known from articulated fish, Vergoossen (1997) erected the new genus Zemlyacanthus. Here we recognise the validity of this genus, based on the features listed here.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD4FFEB5A1C8B97FE8924ED.taxon	description	(Fig. 3 H – J; Table 1; Suppl. 1, figs. 18, 22)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD4FFEB5A1C8B97FE8924ED.taxon	materials_examined	Type material — Holotype scale LGMTI 35 - 360; paratypes LGMTI 35 - 358, 35 - 355, 35 - 354, 35 - 340, 35 - 341, 35 - 342, 35 - 350; Pod’emnaya River, outcrop 67, bed 12, October Revolution Island, Severnaya Zemlya Archipelago, Russia, Severnaya Zemlya Formation (Lower Devonian, Lochkovian). Referred specimens — Scales at levels 513 ’ (156.4 m), 549 ’ (167.3 m), 554.5 ’ (169.0 m), and 556.5 ’ (169.6 m) in the BC II section, including three scales at 556.5 ’ (Suppl. 1, fig. 22), and AMF 97961, 97962 (both level 513 ’ = 156.4 m), figured by Parkes (1995, fig. 33.9 – 33.12): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD4FFEB5A1C8B97FE8924ED.taxon	description	Description — Scales from level 556.3 ’ (169.6 m) strongly resemble flank scales from the type, articulated specimens of Zemlyacanthus menneri, showing overlapping apposed crown growth zones extending back from close to the anterior margin of the scale crown (Fig. 3 H – J). This anterior margin lacks well-formed ridges, with just a few short low rounded ridges occasionally present near the middle of the margin. The apposed growth zones forming the crown are denticulated, particularly in the larger more posterior zones, and sometimes comprise lines of slits / overlaps, rather than having uninterrupted overlaps. There is a sharp rim between the neck and base of the scale, with the latter protruding slightly in front of the crown. The convex base and concave neck are of similar heights. Comparison — Some scales represented in the BC II samples closely resemble those from the type, articulated fishes (Valiukevičius 1992, pl. 10) from the Lochkovian of October Revolution Island. Those BC II scales (Fig. 3 F, G), tentatively assigned to Gomphonchoporus hoppei (Gross 1947), are similar to some of the smaller scales on the type Z. menneri fish (Valiukevičius 1992, pl. 10.8), and they are found at the same level as the scales readily assigned to Z. menneri. Overlap of scale morphotypes between different taxa is a common problem in taxonomy based on isolated scales, particularly when samples are rich in taxa but poor in numbers. Also, recognition that both scales with and without a pore canal system can belong to a poracanthodid species (e. g., Vergoossen 1999 a, Burrow 2013) further complicates taxonomic assignments.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD5FFEB58658C69FF2C239E.taxon	type_taxon	Type species — Trundlelepis cervicostulata Burrow, 1997.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD5FFEB59DC8CD9FA692094.taxon	description	(Fig. 3 K – 3 P; Table 1; Suppl. 1, figs. 18 – 21)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD5FFEB59DC8CD9FA692094.taxon	diagnosis	Diagnosis — see Burrow (2002).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD5FFEB59DC8CD9FA692094.taxon	materials_examined	Type material — Holotype scale MMMC 02239; paratypes scales MMMC 02236, 02234; GSNSW locality C 607, near Trundle, central New South Wales, Australia, Connemarra Formation (Lower Devonian, Lochkovian). Referred specimens — Scales were recovered from most levels from 513 ’ – 532 ’ (156.4 - 162.2 m), including UCR 944 - 3, - 12, - 17 (level 527.25 ’ = 160.7 m), UCR 10768 - 4 (level 518.3 ’ = 158 m), and thin sections UCR 944 - 22, - 23 (level 527.25 ’ = 160.7 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD5FFEB59DC8CD9FA692094.taxon	description	Description — Scales have a flat crown, longer than wide, with 6 – 8 strong ridges leading back from the anterior margin and tapering out before the central area of the crown (Fig. 3 K, M, N). The median ridges are often slightly asymmetrical in cross section, being steeper on the outer face, but the area between these ridges is at the same level as the rest of the crown, without a median sulcus. Some scales have one or two round pores opening out through the outer growth zone in the posterior half of the scale. The neck is deep all round, with ‘ buttressing’ posteriorly. The large, convex base usually protrudes in front of the anterior margin of the crown, sometimes to the extent that the bulk of the base is forward of the crown (Fig. 3 O). As with other scales from the section, hyphal borings penetrate densely, but the tissues forming the crown (Fig. 3 O, P) are recognisable as syncitial mesodentine (sensu Valiukevičius and Burrow 2005) and orthodentine. Unlike poracanthodids with extensive pore canal systems, growth zones are discernible in the whole crown. Wide-calibre pore canals form a simple system comprising a few vertical canals from the undersurface to the upper surface of the crown, near the lateral edges (Fig. 3 P). Comparison — The scales show a range of profiles and crown ornament, comparable with that in the type material from the Lochkovian of southeastern Australia (Burrow 1997, 2002, figs. 21 A – 21 F, 23 A – 23 D, 32 A – 32 G). This taxon represents perhaps the last stage in the loss of a pore canal system in the scale crown for poracanthodids – a progression noted by Vergoossen (e. g., 1999 a) – with only some scales having vertical, unconnected canals penetrating the outermost crown growth zones. Several other latest Silurian or earliest Devonian scales with comparable morphology from other regions could also be from Trundlelepis cervicostulata, including ones from the Přidolí of the Klonk Beds, Czechia (Märss 1997, pl. 7.3 – 7.10: captioned Gomphonchus sp. 3, Gomphonchus sp.) and Sweden (Vergoossen 2002 b, fig. 45: captioned Acanthodii gen. et sp. indet.). The lack of distinctive crown features can make identification of scales from this species difficult when based only on morphology, as several latest Silurian – earliest Devonian taxa also have scales with a deep neck, convex anteriorly protruding base, and a flat crown with subparallel or radial ridges along the anterior margin. For example, Arenaceacanthus arcuatacanalis Valiukevičius (2004 a) and Bracteatacanthus assiduus Valiukevičius (2004 a) from the Přidolí of Lithuania, Nostovicina paravolborthi (Valiukevičius 2003 b) from the Přidolí of Timan – Pechora, and Nostolepis tcherkesovae Valiukevičius (1994) from the Lochkovian of Taimyr and Timan – Pechora have a similar morphology, but none of these taxa have morphotypes with the simple vertical canals penetrating the posterior crown growth zones exhibited in some scales of Trundlelepis from the type locality as well as the BC II section.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED587F8DE9FCBB22E3.taxon	type_taxon	Type species — Gomphodus sandelensis Pander, 1856.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED5A338C36FAEF2215.taxon	materials_examined	Type material — Holotype NNM 423013; paratypes NNM 423014 – 423023, NNM 423044, NNM 423045; East Baltic derived erratic limestone boulder 62, Oosterhaule, northern Netherlands, Late Silurian (Přidolí).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59D68E7FFC472324.taxon	description	(FIG. 3 S-V; TABLE 1; SUPPL. 1, FIGS. 1 – 3, 11, 12, 13)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59D68E7FFC472324.taxon	diagnosis	Diagnosis — Relatively large Gomphonchus scales with a smooth crown that extends beyond the base all round, and a high neck with vertical ribbing posteriorly. Scales have durodentine superficially in some of the youngest crown growth lamellae; they lack radial vascular canals.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59D68E7FFC472324.taxon	materials_examined	Type material — The syntype scales from the Ohesaare Beds, Ohesaare Cliffs (Pander 1856, pl. 6 figs, 15, 16; Ohesaare Formation) and Sandla (Pander 1856, pl. 6 fig. 17; lower Kaugatuma or upper Kuressaare Stage), Saaremaa Island, Estonia (Late Silurian, Přidolí) have been long lost. Referred specimens — Scales assigned to this species are rare compared to the number of poracanthodid scales, occurring at various levels from 395 ’ – 545 ’ (120.4 - 166.1 m), including UCR 930 - 7 (level 395 ’ = 120.4 m) and UCR 10746 - 11 (level 430.5 ’ = 131.2 m); AMF 97957, 97958 (level 513 ’ = 156.4 m), figured by Parkes (1995, fig. 33.1 – 33.4) and thin sections AMF 97994, 97995 (level 513 ’ = 156.4 m), figured by Parkes (1995, fig. 42.1, 42.2): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59D68E7FFC472324.taxon	description	Description — Scales have a smooth flat crown, sometimes with a shallow median sulcus (Fig. 3 S, T) or very weak short ridges along the anterior margin (Fig. 3 U, V); the crown is usually wider and longer than the base. The scales can be difficult to distinguish from those Poracanthodes punctatus scales, which also have a smooth flat crown, with pore openings often only detectable in SEM images.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59BA88A6FDD1224D.taxon	description	(FIG. 3 Q, R; TABLE 1; SUPPL. 1, FIGS. 2)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59BA88A6FDD1224D.taxon	materials_examined	Referred specimens — A few sensory line scales were recovered from levels 395 ′ – 492.3 ′ (120.4 – 150.1 m) in the BC II section, including UCR 10750 - 9 (level 456.5 ’ = 139.1 m) and UCR 930 - 3 (level 395 ’ = 120.4 m), AMF 97928 (level 503 ’ = 153.3 m), AMF 97929 (level 446.5 ’ = 136.1 m) figured by Parkes (1995, fig. 29.9 – 29.12: captioned Chondrichthyan 1, 2), AMF 97949, 97952 – 97954 (all level 402 ’ = 122.5 m), AMF 97955 (level 395 ’ = 120.4 m) figured by Parkes (1995, fig. 32.5, 32.6, 32.11 – 32.16: captioned Poracanthodes punctatus); fragments of dentigerous jaw bone are from levels 424.9 ’ (129.5 m), M 48 B = 491.8 ’ (149.9 m), and M 48 C = 492.3 ’ (150.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD3FFED59BA88A6FDD1224D.taxon	description	Description — Short, wide scales are identified as ones that edged the sensory lines on the head, by comparison with squamation of articulated poracanthodid Zemlyacanthus menneri (Valiukevičius 1992, pl. 9.6 a, 6 b). These scales have a similar structure in all known poracanthodids, with multiple short sharp ridges and tubercles along the straight anterior margin overlapping similar ridges which cover the crown, or at least the anterior half of the crown with the posterior half showing rows or lines of pores. The posterior edge has often fractured off, revealing the posteriorly directed canals of the pore system. Pores open out on the crown between the ridges and tubercles. The neck is short and concave, and the base is low and slightly convex. Other elements include jaw fragments that are probably poracanthodid, because no other ischnacanthiform elements are found at the same levels.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEE59BB8D0FFF3321B3.taxon	materials_examined	Type material — Holotype scale MB. f. 11937 (Brotzen 1934, pl. 1.11 a-c) is from erratic limestone boulder Bey. 36 or 37, northern Germany (Lower Devonian, Lochkovian).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEE59C68BA3FDB02233.taxon	type_taxon	Type species — Nostolepis fragilis Valiukevičius, 2003 a.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEE59C68BA3FDB02233.taxon	discussion	Remarks — All identifiable scales of the Nostolepis - type sensu lato (e. g., Gross 1947, 1971) recovered from the BC II section, except those assigned to Nostolepis matukhini, correspond to species that have been reassigned to Nostovicina Valiukevičius and Burrow (2005), which all lack Stranggewebe (short parallel-oriented mesodentine tubules) in the crown.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEF5A008C49FDCC2079.taxon	description	(FIG. 4 B – D, 4 J; TABLE 1; SUPPL. 1, FIGS. 19)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEF5A008C49FDCC2079.taxon	materials_examined	Type material — Holotype LIGG 30 - 1569; Uryum Beds, Tareya River, Taimyr, Russia (Lower Devonian, Lochkovian). Referred specimens — Scales assigned to this species occur at levels 517 – 613 ’ (157.6 – 186.8 m), and include UCR 10768 - 6, - 10 and thin section UCR 10768 - 11 (level 518.3 ’ = 158 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEF5A008C49FDCC2079.taxon	description	Description — Small scales up to 0.4 mm wide, with crowns mostly conforming to two morphotypes, both of which have a smooth flat subtriangular surface with five or six short, usually smoothly rounded and nonbranching, ridges leading back from the anterior crown margin. Posterolateral edges of the crown are straight or slightly convex and lack denticulations, converging at a slightly obtuse angle. One morphotype has several oblique ridges leading back from the posterior corner along the lateral faces of the crown (Fig. 4 B), and the other morphotype lacks ridges on the posterolateral sides of the crown (Fig. 4 C, D). All scales have a short or no neck. The base is convex and about the same height as the crown plus neck, lacking a marked rim between the neck and base. As usual for BC II scales, histology is poorly preserved with scales having extensive hyphal borings. Four wide growth zones form the crown (Fig. 4 J).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD0FFEF5A008C49FDCC2079.taxon	discussion	Comparison — This taxon was erected for circa 5000 isolated scales from the Lochkovian of Taimyr by Valiukevičius (1994), who originally assigned the species to Nostolepis; it was subsequently reassigned to Nostovicina Valiukevičius and Burrow (2005), based on histological structure. Some scales from Timan – Pechora that Valiukevičius (1994) assigned to this species were reassigned to Nostolepis adzvensis Valiukevičius (2003 b) and subsequently by Valiukevičius and Burrow (2005) to Pechoralepis adzvensis, based once again on histological differences. The two species Nostovicina laticristata and Pechoralepis adzvensis are virtually impossible to differentiate on morphology alone, but histological study of scales confirmed that those from BC II are N. laticristata. The latter show a similar range in size and morphology to scales from the Lochkovian of the Arctic Canadian Archipelago, which Vieth (1980) assigned to Gomphonchus sp. cf. G. hoppei, and which have since also been assigned to N. laticristata (Valiukevičius 1994, Turner and Burrow 1997: CJB, personal observation of scales from GSC localities C- 8771, C- 67653, C- 76085). A partial articulated fish from the Lochkovian MOTH locality of Northwest Territories, Canada (Hanke 2001, figs. 82 – 85: captioned as Nostolepis tewonensis?) is here considered to be Nostovicina laticristata. Lochkovian – Pragian scales from southeastern Australia that are now assigned to Nostovicina guangxiensis (Wang, 1992) have a very similar or greater range of crown morphotypes (Burrow 2002, figs. 4 E – I, 5 J – M, 12 A, C, D), but these scales are on average much larger than those of N. laticristata. One of the type scales of Nostolepis tewonensis (Wang et al. 1998, pl. 1 H) from the lower Lochkovian of the Xiaputonggou Formation, Tewo county, China, resembles the simplest variants of Nostovicina laticristata, and it seems possible that the Chinese scales from that level should be reassigned to the latter species. The holotype and other paratype scales of N. tewonensis were from the much older, upper Wenlockian Miaogou Formation. N. laticristata is now recorded from the Lochkovian of arctic Canada, Northwest Territories Canada, Nevada, Taimyr, Podolia, and east Baltic countries (Valiukevičius 1994, 2000, Turner and Burrow 1997).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFD1FFEF5AF688A6FA792553.taxon	materials_examined	Type material — Holotype IVPP V 9745.1; Paratypes IVPP V 9745.2 – 4 and thin section IVPP V 9745.5; Ertang Formation, Guangxi, China (Lower Devonian, Emsian).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCEFFF059DB8F4CFC7921D4.taxon	materials_examined	Type material — Holotype scale LIGG 30 - 1604; Uryum beds, Tareya River, Taimyr, Russia (Lower Devonian, Lochkovian).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF15ADE8A79FA952382.taxon	type_taxon	Type species — Funicristata nevadaensis n. sp., by monotypy. Zoobank LSID — urn: lsid: zoobank. org: act: FD 6 D 940 A-FAFF- 4 FFE- 9 E 35 - 042 B 7 EBC 2315	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF15ADE8A79FA952382.taxon	diagnosis	Diagnosis — as for the species. Occurrence — Roberts Mountains Formation, central Nevada (Late Silurian, Přidolí).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF15ADE8A79FA952382.taxon	etymology	Etymology — Funis, Latin for rope or cord, referring to the appearance of the crown ridges, and crista, Latin for crest or ridge.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF15ADE8A79FA952382.taxon	discussion	Remarks — These scales have a highly distinctive crown ornament, not observed in any known scale taxa. The poor preservation of histological structure of scales from this level in the section, with dense hyphal borings through the base and crown, obscures details that could help assign them to a family or order.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF159D58DF6FBC626F8.taxon	description	(FIG. 4 Q – T; TABLE 1)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF159D58DF6FBC626F8.taxon	materials_examined	Type material — Holotype LIGG 30 - 1627; Uryum beds, Taimyr, Russia (Lower Devonian, Lochkovian). Referred specimens — Scales assigned to this species occur at levels 527.25 ’ (160.7 m) and 562.6 ’ (170.1 m) and include UCR 5443 - 2, - 5 (level 562.6 ’ = 170.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF159D58DF6FBC626F8.taxon	description	Description — Scales with a distinctively ornamented crown, with 5 – 7 strong, smooth subparallel or radial ridges that bifurcate towards the anterior margin. Posterolateral edges of the crown are straight and smooth, converging at a slightly obtuse angle at the posterior corner (Fig. 4 Q – T). The base is moderately convex, and the neck has only small pore openings. Scarcity of material precluded thin sectioning to examine histology. Comparison — The crown ornament on N. matukhini scales is very distinctive, with all ridges bifurcating along the anterior margin, a feature not shown in any other nostolepid-type scales.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF158738D63FD7B2269.taxon	type_taxon	Type species — Nostolepis striata Pander, 1856.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	description	(FIG. 5; TABLE 1; SUPPL. 1, FIGS. 2, 5 – 7, 9 – 11, 14) Zoobank LSID — urn: lsid: zoobank. org: act: 1 BB 5 B 9 FC- 3 E 9 B- 4 F 4 B-B 238 - A 25 CA 0 E 9 A 8 D 8	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	diagnosis	Diagnosis — Acanthodian with small scales up to 0.5 mm wide and 0.6 mm long; crown with strong branched ridges with a ‘ twisted’ appearance leading back from anterior edge and converging towards posterior corner of crown, or at least extending past lateral corners of crown; neck low or absent anteriorly on most scales, with only small pore openings; base only slightly convex and deepest below anterior margin of crown; crown extends up to a base-length beyond posterior corner of base; four or five superposed crown growth zones with a thin enameloid top; wide-calibre canal extends from primordial crown growth zone to posterior corner of crown, its presence usually marked by longitudinal ridge on crown.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	materials_examined	Holotype — Holotype scale UCR 10750 - 3 (Fig. 5 A – C); 456.5 ’ (= 139.1 m) level, BC II section, Roberts Mountains, Eureka county, central Nevada, U. S. A.: Roberts Mountains Formation (Late Silurian, Přidolí). Paratypes — Paratypes scales UCR 10750 - 2, UCR 10746 - 8, - 10, thin sections UCR 10750 - 10, 12. Referred specimens — Forty-three scales including the type specimens. Occurrence — Only known from the type locality at levels 395 – 492.3 ’ (120.4 – 150.1 m).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	etymology	Etymology — Nevada, for the U. S. state where the type material was found, and ensis, Latin suffix denoting place.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCFFFF35A258CDFFC92260C.taxon	description	Description — Scales are small, up to 0.5 mm wide, 0.6 mm long and 0.3 mm high. Most scales appear dorsoventrally compressed, with a low or absent neck anteriorly on most scales (Fig. 5 A – E). The crowns have a distinctive ornament comprising branching ridges with a ‘ twisted’ or rope-like appearance leading back from the anterior edge, extending towards the posterior corner of crown (Fig. 5 A – G), or at least extending past the lateral corners of the crown (Fig. 5 H, I). The crown extends up to a base-length beyond the posterior corner of the base, with most scales having a marked median ridge running back from the middle of the scale to the posterior tip (Fig. 5 A, E, I). In many scales, particularly the more ‘ flattened’ examples, the crown ornament resembles a branching tree, with the posterior median ridge being the trunk with the radiating, branching ridges extending out towards the anterior edges. The neck has only small pore openings (Fig. 5 I). The base on all scales is only slightly convex and deepest below the anterior margin of the crown, with a marked rim between the base and neck. Histological preservation is poor at these levels, with extensive hyphal borings, so that only general features can be discerned. The crown has four or five growth zones with all except the embryonic zone being extremely thin under the crown surface, comprising only enameloid posterior to the apex of the base (Fig. 5 J, L). A wide calibre canal runs from the embryonic zone up and back through the middle of the posterior crown, aligned with the median ridge on the crown surface, to the posterior corner (Fig. 5 J, K). Fine branching dentine tubules rise up in the anterior parts of the crown. No bone cell lacunae are detectable in the base. Comparison — These scales differ from all known taxa, based on their distinctive crown ornament resembling a tree with successively branching ridges. The single large canal extending from the primordial zone back to the posterior corner could indicate that the taxon is a highly derived poracanthodid, but no poracanthodids resemble this species in morphology or position of pore canals.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35986899AFA8D264B.taxon	description	(FIG. 6 A – C; TABLE 1; SUPPL. 1, FIGS. 4, 5,? 20)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35986899AFA8D264B.taxon	materials_examined	Type material — Holotype GSC 2, Member A, Red Canyon River Formation, Ellesmere Island, Canada (Lower Devonian, Lochkovian). Referred specimens — Rare scales in BCII at level 430.5 ’ (131.2 m) and possibly another very large scale at level 525 ’ (160 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35986899AFA8D264B.taxon	description	Description and comparison — The scales at the lower levels have a broad central longitudinal ridge flanked by narrow ridges paralleling the central ridge. All ridges extend the length of the crown. The base is concave with a sub-diamond outline. The morphology conforms to that of the type scales from the Lochkovian Member A, Red Canyon River Formation, Ellesmere Island, Arctic Canada, figured by Vieth (1980, pl. 9).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF3584C8914FD6E26D8.taxon	type_taxon	Type species — Ellesmereia schultzei Vieth, 1980.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35A868E97FA4C205D.taxon	type_taxon	Type species — Lophosteus superbus Pander, 1856.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	type_taxon	Type species — Polymerolepis whitei Karatajūtė-Talimaa, 1968.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	description	(FIG. 6 D; TABLE 1; SUPPL. 1, FIGS. 5, 7, 11, 14)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	materials_examined	Referred specimens — Very rare, one scale at level 458.67 ’ (139.8 m) and possible scale fragments from 430.5 ’ (131.2 m), 453 ’ (138.1 m), 492.3 ’ (150.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF35AEE89DDFB592156.taxon	description	Description and comparison — The scales and scale fragments have finely noded ridges. The scale base is always flat or concave. The type material of P. whitei from the Lochkovian of Podolia shows a wide range of scale morphotypes (e. g., Obruchev and Karatajūtė-Talimaa 1967, pl. 2 figs. 1 – 4, Karatajūtė-Talimaa 1998, figs. 6, 7). Hanke et al. (2013, figs. 1 – 5) demonstrated in their description of a partial articulated specimen from the Lochkovian MOTH locality in the Northwest Territories, Canada assigned to P. whitei, comprising an anal fin and part of the caudal fin and peduncle, that the scale variation over the body is even greater than seen in the type scales. Specimens referred to P. whitei from the younger Lochkovian (delta conodont Zone) Windmill Limestone, Simpson Park Range, Nevada include head, fin, and body scales (Turner and Murphy 1988, table 1, figs. 2.14, 15, 20, 22 – 26). The Nevadan scales are the first record in the Silurian for this taxon. Given the morphological variation in scales from the known localities, it seems possible that more than one species is represented, so we only refer the BC II specimens to an open taxon within the genus rather than to the type species.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCDFFF45AD98F1AFEB32686.taxon	materials_examined	Type material — Pander’s specimens have long been lost, so Gross (1969) erected a neotype, scale Tü Pi 1359 / 1 (Gross 1969, fig. 1 A, B, 2 H 1 - 3); Ohesaare Regional Stage, Ohesaare Cliff, Saaremaa, Estonia (Upper Silurian, upper Přidolí).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF4599F8F1EFAE224B3.taxon	description	(TABLE 1; SUPPL. 1, FIGS. 7, 11, 12, 14, 18)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF4599F8F1EFAE224B3.taxon	materials_examined	Referred specimens — Scale fragments were collected from BC II section at six levels from 430.5 ’ to 513 ’ (131.2 - 156.4 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF4599F8F1EFAE224B3.taxon	discussion	Remarks — Most remains are conjoined tesserae such as the three small irregular tesserae from level 458.67 ’ (Suppl. 1, fig. 11). Some (Suppl. 1, figs. 7, 14, 18) resemble traquairaspid remains with slender oak-leaf pattern tubercles: traquairaspids typically range from Přidolí to early Lochkovian. One plate from level 468 ’ (Suppl. 1, fig. 12) is pteraspid- or poraspid-like, typical of early Lochkovian elsewhere (e. g., Turner et al. 2017). Turner and Murphy (1988, fig. 1.1 - 6, 8 - 15, 24) described heterostracan microremains from the Lochkovian Simpson Park section, Nevada. Parkes (1995) also identified heterostracan remains in two levels of BC II (402 ’, 446 ’). As yet, there is no major review of heterostracan dermal scales; a handbook and major description of Cornwallis Island fauna are awaited (D. K. Elliott pers. comm. 2021, Thorsteinsson and Elliott 2022).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	type_taxon	Type species — Thelodus scoticus Traquair, 1898.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	description	(TABLE 1; SUPPL. 1, FIGS. 1, 4)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	materials_examined	Referred specimens — One scale from BCII level 27 ’ (8.2 m); two scales from level 430.5 ’ (131.2 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCAFFF55AB58DD3FEDD26A2.taxon	description	Description and comparison — Elongate teardrop-shaped scales with two sharp crown ridges. The base is oval and extends about two-thirds crown length. There is no anterior basal spur. This scale resembles those described as Loganellia cuneata (Gross 1947, pl. 3; 1967, pl. 3) from the Přidolí of Britain, Europe, and Russia (Märss et al. 2007) but also is similar to the much older L. sulcata and L. prolata (Märss et al. 2002) from the Lower Silurian of arctic Canada. Without more material, the designation can only be tentative.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCBFFF55A918ECCFA112007.taxon	type_taxon	Type species — Thelodus alatus Gross, 1947.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCBFFF559E28A46FF592474.taxon	type_taxon	Type species — Trimerolepis lithuanica KARATAJŪTĖ-TALIMAA in OBRUCHEV & KARATAJŪTĖ-TALIMAA, 1967.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCBFFF559E28A46FF592474.taxon	discussion	Remarks — The scales of this genus type are rare and found in the lower part of the BC II section, hence our identifications are tentative. Trimerolepis species occur mostly in the Přidolí to lower Lochkovian (Märss et al. 2007).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCBFFF75AA08F5FFE982531.taxon	materials_examined	Type material — Holotype scale MB. f. 410 (Gross 1947, pl. 1 fig. 5 a, b), Beyrichienkalk, Danzig (now Poland) (uppermost Silurian, Přidolí). Referred material — Three scales from BCII level 430.5 ’ (131.2 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFCBFFF75AA08F5FFE982531.taxon	description	Description and Remarks — These specimens are typical of the taxon, with one transitional cephalo-pectoral and two trunk scales (see e. g., Gross 1947, 1967). Distribution is in the Přidolí of Europe, Britain, and Russia and possibly into lowermost Lochkovian (Märss et al. 2007).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF75AC48C84FC1C2268.taxon	type_taxon	Type species — Boreania minima Karatajūtė-Talimaa, 1985.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF75A138DF7FA942172.taxon	materials_examined	Type material — Holotype scale LitNIGRI no. 35 - 456 (Karatajūtė-Talimaa 1985, fig. 1.24); obn. 4, sl. 3, Matusevich R., October Revolution Island, Severnaya Zemlya, Russia: Pod’yemnaya Formation (early Lochkovian, Lower Devonian) (NB. might be lost).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF7584C8C56FEFA21CB.taxon	type_taxon	Type species — Lanarkia horrida Traquair, 1898.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF7584C8C56FEFA21CB.taxon	description	(FIG. 7 C; TABLE 1; SUPPL. 1, FIG. 11)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF7584C8C56FEFA21CB.taxon	discussion	Referred specimens and Remarks — At least two possible scales from BC II section: one from level 458.67 ’ (139.8 m), one from level 527.25 ’ (160.7 m) (Fig. 7 C). Lanarkia species are known mainly from earlier Silurian rocks in Scotland, mainland Europe, and arctic Russia, as well as in arctic Canada (Märss et al. 2007). The scale from 527.25 ’ is most like those called Thelodus traquairi by Gross (1967), originally “ Lanarkia costata ” of Gross, 1947, from the north German Beyrichienkalk (Bey. 1, early Přidolí) and ones from Poland (late Přidolí; Gross 1947, Märss 1997), which have been referred to Lanarkia (Märss et al. 2007).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF758478F72FA8523BB.taxon	type_taxon	Type species — Cephalopterus pagei Powrie, 1870.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF758478F72FA8523BB.taxon	description	(FIG. 7 D; TABLE 1; SUPPL. 1, FIGS. 5, 9)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF758478F72FA8523BB.taxon	materials_examined	Referred specimens — Possibly three scales in BCII section: two at level 430.5 ’ (131.2 m) and one at 456.5 ’ (139.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF758478F72FA8523BB.taxon	description	Description — One scale in 430.5 ’ is a robust trunk scale with the posterior tip broken off, by which the central large pulp canal can be seen. The base is extended anteriorly into a wide spur. A further possible trunk scale is boat-shaped with a poorly preserved crown with prominent ridges and a median narrow platform, a wide shallow neck and a small anterior prong on the large ellipsoid base (Fig. 7 D). A broken trunk scale from level 456.5 ’ has a posteriorly expanding and possibly high crown. The undersurface of the posterior crown in a trunk scale has a strong median rib and three to four lateral ones (Suppl. 1, fig. 9). There is a broken anterior rounded base with a large pulp opening.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC9FFF758478F72FA8523BB.taxon	discussion	Remarks — These few scales resemble those of the type species and might be Turinia pagei but their preservation is poor and / or they are broken and this taxon does not usually occur below the Siluro-Devonian boundary. Turiniid scales with several ventral crown ribs are also seen in Turinia barentsia from the Lower Devonian Red Bay Group of Spitsbergen (Blom and Goujet 2002, e. g., pl. 1.6, 8). Turinia - like scales have been recorded in some localities such as the Welsh Borders and Irian Jaya (Märss et al. 2007, Turner et al. 2017).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC6FFF859B58D63FB182284.taxon	type_taxon	Type species — Nikolivia balabayi Karatajūtė-Talimaa, 1978.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC6FFF859B58D63FB182284.taxon	description	(FIG. 7 E – J; TABLE 1; SUPPL. 1, FIGS. 5, 9, 20, 25)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC6FFF859B58D63FB182284.taxon	materials_examined	Referred material — Rare except for one level; c. 15 specimens from section BC II: one scale AMF 97875 from 402 ’ (122.5 m) – this specimen is missing; c. 11 from 430.5 ’ (131.2 m), 456.5 ’ (139.1 m); level 527.25 ’ (160.7 m); one specimen from level 591.5 ’ (180.3 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC6FFF859B58D63FB182284.taxon	description	Description and comparison — AMF 97875 and the other Nikolivia scales from BC II, notably from 430.5 ’, resemble scales of N. gutta, N. aligera Karatajūtė-Talimaa, 2002 (Fig. 7 A-E), and N. auriculata Märss et al., 2002 (Fig. 7 F). These nikoliid taxa are found in the early Lochkovian elsewhere (Märss et al. 2007). The specimen that Parkes (2005, fig. 22.17, 18; Fig. 7 G) captioned as Amaltheolepis sp. cf. A. winsnesi from 402 ’ is a typical nikoliviid scale, bilaterally symmetrical, small (0.4 mm long x 0.3 mm wide) and rounded. The central squat teardrop-shaped crown section is smooth and rounded anteriorly and raised slightly, curving to a posterior point with three short anterior ridges that extend less than a quarter scale length. There is a pair of lateral flattened lappets with a simple but slightly imperfect (damaged?) rim with small scallop-shaped concavities, two on one side and one on the other. The central surface of the crown is smooth with a broad middle raised ridge extending from the midpoint near the base to the posterior point. The neck is smooth and low. The anteriorly placed base is a rounded torus: relatively smooth, deep, and mature with a smaller central rounded pulp opening. One possible thelodont specimen (Suppl. 1, fig. 25:?) from level 591.5 ’ just above the S – D boundary appears typical of Nikolivia gutta Karatajūtė-Talimaa, 1978 with its smooth heart-shaped crown.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC6FFF859B58D63FB182284.taxon	discussion	Remarks — Parkes (1995) interestingly misidentified scale AMF 97875 (Fig. 7 G) as an amaltheolepid. Here we refer it to Nikolivia sp. But there are not enough scales in the Nevadan material to judge the variation. Nikoliviid scales are typical of the Early Devonian (Lochkovian) in Europe, and elsewhere in North America (Märss et al. 2007). The small regular concavities on the rim of the lateral lappets of the specimen might be damage made in handling the specimen or a pathological feature as they resemble bite-marks, but this has not been seen elsewhere. Lepidophagy is common in modern bony fishes and it is feasible that the scale was attacked in life or alternatively post-mortem by another fish or even by an unknown invertebrate.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFF959EA8F5FFA6B27F3.taxon	type_taxon	Type species — Barlowodus excelsus Märss et al., 2002.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFF95A2D894CFC3E2530.taxon	materials_examined	Type material — Holotype scale UALVP 44700 (Märss et al. 2002, pl. 1, fig. 18), upper Barlow Inlet Formation, southern Read Bay section, Cornwallis Island, Canadian Arctic Archipelago (lowermost Devonian, lower Lochkovian).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFF959F48BE6FE482324.taxon	materials_examined	Type material — Holotype scale LitNIGRI no 15 - 494 (Karatajūtė-Talimaa 1978, pl. XLII. 6 a, b), Zalyeshchiki, Podolia, Ukraine (Lower Devonian, Lochkovian, Ivanov horizon). [might be missing]	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFF959178AA8FF2C2459.taxon	type_taxon	Type species — Nikolivia elongata Karatajūtė-Talimaa, 1978.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFFA5AB28A0FFD4B2308.taxon	description	(FIG. 7 P- S; TABLE 1; SUPPL. 1, FIG. 4) Referred specimens — one scale from BC II level 430.5 ’ (131.2 m); one from level 527.25 ’ (160.7 m); one scale AMF 97874 from BC II level 875 ’ (266.7 m); this last specimen is missing: Roberts Mountains Formation. Description and comparison — A scale figured by Parkes (1995, fig. 22.15, 16, captioned as? nikoliviid gen. et sp. indet.; Fig. 7 P, Q) is c. 0.4 mm long with a broken posterior crown, which rises quite steeply posteriad. The dorsal crown is elongated and subdivided into three with a raised central section with two high flat-topped ridges with a deep central groove anteriorly that flattens posteriad. Laterally there are expanding lappets, one anteriorly seen to the left, also with a bifurcate dorsal ridge that extends about one-third of the crown, and on the left a series of two broken and one complete ridge that extends about two-thirds of crown length. The posterior points of the lappets tend to be rounded but are also broken. A flattened lateral ridge then extends from the base of the lappets towards the broken posterior tip. The ventral crown is covered with an ultrasculpture of fine parallel striae extending from the anterior crown / neck interface to the posterior tips of the lateral lappets and posterior section of the broken crown. The neck itself is relatively shallow and unornamented. The base is oval, extending about one-quarter of the estimated length of the scale. It is relatively mature with a thick torus surrounding the large central oval pulp opening and with a slight anterior thickening. One small, rounded scale has a strong tripartite crown with deep grooves between the high flat ridges. It is most like the simpler cephalopectoral or trunk of B. tridens (e. g., Märss et al. 2006, text-fig. 65) from the Přidolí Barlow Inlet Formation of Cornwallis Island. The scale from level 527.25 ’ is tricuspid with clear striated ridges on the sides of the cusps (Fig. 7 R, S).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC7FFFA5AB28A0FFD4B2308.taxon	discussion	Remarks — Märss et al. (2002, 2006) discovered the thelodont genus Barlowodus in the southern section eastern Cornwallis Island at Read Bay (RBBI and RBBI *), which became the stratotype for the Přidolí Barlow Inlet Formation that is formed from argillaceous carbonate marine rocks. At 59.0 m from only one sample, Märss et al. (2002) identified three taxa, Barlowodus tridens, B. excelsus, and B. floralis, the latter doubtfully. Barlowodus tridens sensu stricto is only known elsewhere from Cornwallis Island. However, scales possibly from this, as well as the other two species of this genus, were recorded from the late Přidolí Barlow Inlet Formation by Märss et al. (2006, pp. 124 - 126). The fine microornament on the scale figured by Parkes (1995, fig. 22.15,16; Fig. 7 P, Q) is similar to that in other Devonian taxa such as Neoturinia spp., Barlowodus florialis and even Boothialepis thorsteinssoni (Märss et al. 2006, pl. 16). Such fine ridging on the scales might have contributed to drag reduction (e. g., Reif 1985). It is unusual in the Nevadan case being on the ventral surface of the crown; we tentatively refer it to B. sp. cf. tridens. However, it is at a level much higher than the other thelodont scales, in the lower to middle Lochkovian.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA59FB8C53FF4E2249.taxon	materials_examined	Type material — Holotype scale UALVP 44955 (Märss et al. 2002, pl. 1, fig. 17), upper Barlow Inlet Formation, southern Read Bay section, Cornwallis Island, Canadian Arctic Archipelago (lowermost Devonian, lower Lochkovian).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA5D438B70FA6B2329.taxon	description	(TABLE 1; SUPPL. 1, FIG. 7)	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA5D438B70FA6B2329.taxon	materials_examined	Referred specimens — two scales from BCII section level 453 ' (138.1 m); two scales from BC II section level 527.25 ' (160.7 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA5D438B70FA6B2329.taxon	description	Description — These specimens are not well preserved but might be trunk scales of a species of this genus.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	materials_examined	Referred specimens — Circa 20 specimens from BC II level 430.5 ' (131.2 m); two from level 453 ' (138.1 m): Roberts Mountains Formation.	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	description	Description and comparison — Small scales with complex crown sculpture, all with fine ribbed ultrasculpture (Fig. 8 A – K). One possible head or oral scale has a high multi-ridged crown and high neck with a rounded base and large central pulp opening (Fig. 8 A). One possible cephalopectoral scale has a flattened rhombic crown which rises only slightly to a posterior point; fine ultrasculpture as well as borings can be seen on the surface (Fig. 8 B). Most scales are trunk scales. The crowns rise gently posteriad with three flat ridges or a system of bifurcating ridges separated by deep or wide grooves. The posterior or posterolateral crown margin is multi-pointed (Fig. 8 A, C – F, H – K). Most scales in level 430.5 ’ seem affected by fungal damage (as noted for other specimens above). Histology was attempted using anise oil but the structure is disrupted and so we cannot verify the apparent “ criss-cross aspidine ‘ pegs’ ” noted as characteristic for the genus and separate family by Märss et al. (2006, p. 121). However, a similar criss-cross pattern of Sharpey’s fiber bundle spaces is found in other deep and swollen old bases of other thelodont scale taxa such as Thelodus laevis (e. g., Bystrow 1957, Gross 1967).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
B21CD55BFFC4FFFA58678D29FAFB25E7.taxon	discussion	Remarks — Most of the scales from Nevada seem closest to B. floralis. The type locality for the latter is at 34.5 * m in the same section where it co-occurs with the other two Barlowodus species (Märss et al. 2006).	en	Burrow, Carole Jan, Murphy, Michael, Turner, Susan (2023): Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. PaleoBios 40 (4): 1-32, DOI: 10.5070/P940454153, URL: http://dx.doi.org/10.5070/p940454153
