Nostolepis Pander 1856

• Main Author: Burrow, Carole J.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2003
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Acanthodii; Climatiiformes; Climatiidae; Nostolepis; Taimyr
• Online Access: https://doi.org/10.5281/zenodo.5464124; http://treatment.plazi.org/id/020087A632443110FCDAFA274CA3F9E2

Genus Nostolepis Pander, 1856 TYPE SPECIES. — Nostolepis striata Pander, 1856. HOLOTYPE. — Scale figured by Pander (1856: pl. 6, fig. 7) from the Late Silurian (Pridoli) Ohesaare Formation, Saaremaa, Estonia. Nostolepis lacrima Valiukevicius, 1994 HOLOTYPE. — Scale GI N 30-1604 (Valiukevic˘ius 1994: pl. XIX, fig. 10) from outcrop 775, layer 47, Lochkovian Urum Beds, Tareya River, Taimyr, Russia. DIAGNOSIS (after Valiukevic˘ius 1994). — Scales up to 0.6 mm long and 0.3 mm wide; four or five regularlyspaced sub-parallel ridges extending up to half the length of the crown; posterior part of crown narrows to a sharp point; neck low to moderate height; base smaller than crown and weakly convex; crown formed of two to four growth zones filled with simple mesodentine, without any wide canals; numerous lacunae in the embryonic growth zone; abundant fine bone cell cavities in the base. MATERIAL EXAMINED (Table 1). — Eight scales from sample C923 including figured specimen MMMC 2551 (Fig. 4A, B), 24 scales from C925 including figured specimens MMMC 02555-7 (Fig. 2 A-D, H), one scale from Y4, possibly one scale from C920. DESCRIPTION Morphology (Figs 2 A-D; 4A, B) The scales are relatively small, ranging from 0.2-0.4 mm wide and 0.3-0.4 mm long. Scale crowns are simple, with a rounded anterior margin bearing three to five short, sharp ridges which usually rise up directly from the base; on some scales the crown and base are separated by a short neck anteriorly. The ridges are evenly spaced and aligned radially relative to the posterior corner of the crown. The crown plane is horizontal, being smooth behind the ridges and with smooth, sharp postero-lateral edges. Most of the scales have an asymmetrical crown. The base is moderately swollen, with its maximum depth slightly forward of centre; a sharp rim often delineates the base/neck junction. Histology (Fig. 2H) The crown is quite shallow, and the base/crown junction is almost flat. Four growth zones form the crown. Poor preservation and remineralization have ...