Schizocrania incola ( PERNER , 1903)

Mergl, Michal & Nolčová, Lucie, 2016, Schizocrania (Brachiopoda, Discinoidea): Taxonomy, Occurrence, Ecology And History Of The Earliest Epizoan Lingulate Brachiopod, Fossil Imprint 72 (3 - 4), pp. 225-238 : 228

Schizocrania incola ( PERNER, 1903)

Pl. 3, Figs 1–16, Text-fig. 1

1903 Ptychopeltis incola BARR. ; Perner, p. 42, text-figs 15, 16, pl. 43, figs 8–15.

1963 Ptychopeltis incola PERNER ; Horný, p. 63, pl. 15, figs 1–7, pl. 16, figs 1–8.

1972 Ptychopeltis incola PERNER ; Havlíček, p. 232, text-fig. 1, pl. 2, figs 2, 3.

D e s c r i p t i o n. Perner (1903), Horný (1963).

R e m a r k s. The main differences of Schizocrania incola ( PERNER, 1903) from the ancestral S. hornyi ( HAVLÍČEK, 1972) are the high convexity of the dorsal valve, highly arcuate anterior commissure, and finer (capillate instead of costellate) ornamentation in the dorsal valve. The last difference is the most significant. The number of costellae near the anterior margin ranges between 2–4 costellae per 1 mm in the largest preserved dorsal valves S. multistriata ( REED, 1905) and S. hornyi , but there is at least 7–8 costellae in S. incola (Pl. 3, Figs 9, 11, 12–14). This difference is even more striking because the number of costellae per 1 mm in all species of Schizocrania decreases with the shell size, and the measured valves of S. incola are larger than the largest available valves of S. multistriata and S. hornyi . Schizocrania incola is also prominent in high convexity of the dorsal valve. One of the type specimens of S. incola (NM-L 5404) shows a distinct impression of a large visceral area, with clearly defined anterior projection ( Text-fig. 1 , Pl. 3, Fig. 16).

O c c u r r e n c e. Letná Formation, upper part (mid- to late Sandbian) (localities: Trubská gorge, Zahořany).

Figures

Text-fig. 1. Schizocrania incola (PERNER, 1903). Drawings of visceral area and muscle scars.