Fragilaria sublanceolata-baikali (Flower & D.M.Williams) Novais, C.Delgado & S.Blanco

Vijver, Bart Van de, 2021, Type analysis of Fragilaria capucina f. lanceolata-baikali and Fragilaria capucina f. sublanceolata-baikali (Bacillariophyta, Fragilariaceae), Notulae Algarum 181, pp. 1-5 : 2-3

Fragilaria sublanceolata-baikali (Flower & D.M.Williams) Novais, C.Delgado & S.Blanco (in Novais & al. 2019: 139) ( Figs 1–69)

Basionym: Fragilaria capucina f. sublanceolata-baikali Flower & D.M.Williams in Flower & al. (2004), Proceedings of the Seventeenth International Diatom Symposium, Ottawa, p. 92, figs 13 & 15.

Holotype: BM 10032 l ( BM, Natural History Museum , London, UK).

Synonyms: Fragilaria capucina f. lanceolata-baikali Flower & D.M.Williams (in Flower & al. 2004: 92, figs 14, 16), Synedra vaucheriae var. capitellata Grunow sensu Skvortzov (1937 : pl. 4, fig. 1), Fragilaria lanceolata-baikali (Flower & D.M.Williams) Novais, C.Delgado & S.Blanco (in Novais & al. 2019: 139)

Description: Frustules in girdle view not observed, perhaps because of preparation technique. Valves strictly lanceolate in larger specimens becoming more elliptic-lanceolate in smaller valves, with gradually tapering margins. Smaller specimens with clearly convex margins. Apices protracted, subcapitate (larger specimens) to rostrate (smaller specimens). Marginal spines usually present ( Figs 63, 65, 67, arrows indicating spine vestiges), conical, never in the shape of linking spines. Spines occasionally absent, independent from valve length ( Figs 62, 64, 66). Valve dimensions (n=50): valve length 10–45 µm, width 4.0–5.5 µm. Axial area narrow, linear, not widening towards the central area. Central area asymmetrical. One side clearly swollen and depressed, hyaline. Opposite side with several shortened striae. Ghost striae rarely visible, although sometimes present ( Fig. 62, arrows: present, Fig. 64: absent). Striae uniseriate, parallel to very weakly radiate throughout, alternating, becoming slightly more radiate near the apices, 17–20 in 10 µm, composed of small, rounded to apically elongated areolae ( Figs 65–67). Occasionally, several areolae doubled per stria ( Figs 64, 66). Apical pore field well developed, composed of up to six rows of small, squarish pores ( Figs 63, 66). Rimoportula large, present at one apex per valve, replacing part of the last stria ( Figs 63, 66, 67, arrows), oblique. Internally, depressed central area clearly visible ( Fig. 69). Rimoportula transapically elongated, almost straight ( Fig. 68).

We appreciate the nomenclatural advice of Dr Wolf-Henning Kusber.

Desmazières, J.B.H.J. (1830). Plantes cryptogames du nord de la France. nos 451 -500. Lille: issued by the author.

Flower, R.J., Pomazkina, G., Rodionova, E. & Williams, D.M. (2004). Local and meso-scale diversity patterns of benthic diatoms in Lake Baikal. In: Proceedings of the Seventeenth International Diatom Symposium. Ottawa, Canada, 25 th – 31 st August 2002 (Ed. by M. Poulin), pp. 69–92. Biopress Limited, Bristol.

Heudre, D., Wetzel, C.E., Moreau, L., Van de Vijver, B. & Ector, L. (2019). On the identity of the rare Fragilaria subconstricta (Fragilariaceae), with Fragilaria species forming ribbon-like colonies shortly reconsidered. Plant Ecology and Evolution 152 (2): 327–339.

Novais, M.H., Almeida, S.F.P., Blanco, S. & Delgado, C. (2019). Morphology and ecology of Fragilaria misarelensis sp. nov. (Bacillariophyta), a new diatom species from southwest of Europe. Phycologia 58 (2): 128–144.

Skvortzov, B.W. (1937). Bottom diatoms from Olhon Gate of Baikal Lake, Siberia. Philippine Journal of Science 62 (3): 293–377, pls 1–18.

Tuji, A. & Williams, D.M. (2006). Typification of Conferva pectinalis O. F. Müll. (Bacillariophyceae) and the identity of the type of an alleged synonym, Fragilaria capucina Desm. Taxon 55 (1): 193–199.

Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D.L., Herendeen, P.S., Knapp, S., Kusber, W.-H., Li, D.-Z., Marhold, K., May, T.W., McNeill, J., Monro, A.M., Prado, J., Price, M.J. & Smith, G.F., editors (2018). International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile, Vol. 159. pp. [i]- xxxviii, 1-253. Glashütten: Koeltz Botanical Books.

Van de Vijver, B., Williams, D.M., Kelly, M., Jarlman, A., Wetzel, C.E. & Ector, L. (2021). Analysis of some species resembling Fragilaria capucina (Fragilariaceae, Bacillariophyta). Fottea (in press).