Quasimolites quasimodo, Valent, Martin, Fatka, Oldřich, Szabad, Michal, Micka, Václav & Marek, Ladislav, 2015

Valent, Martin, Fatka, Oldřich, Szabad, Michal, Micka, Václav & Marek, Ladislav, 2015, Skryjelites auritus gen. et sp. nov. and Quasimolites quasimodo gen. et sp. nov. — two new middle Cambrian hyolithids (? Mollusca) from the Czech Republic, Zootaxa 4007 (3), pp. 419-426 : 424-425

Quasimolites quasimodo sp. nov.

( Fig. 4 )

1983 Quasilites quasimodo sp. nov.; Marek, p. 44–45.

Holotype. NM L40476 ( Figs 4 A, B, E); inner surface of the operculum.

Paratypes. NM L40475 ( Figs 4 C, F); outer surface of operculum. NM L40719 ( Fig. 4 D); external mould of venter with distinct muscle scars. NM L40474 ( Figs 4 G, H and I); internal mould of conch. All specimens come from the Buchava locality.

Type horizon and locality. Middle Cambrian, Buchava Formation, Skryje Member, Paradoxides (Eccaparadoxides) pussilus Biozone; Barrandian area, Skryje–Týřovice Basin, Buchava locality, Czech Republic (N 49°56'33.0", E 13°44'41.8").

Material. In addition to the holotype, 25 mostly fragmented opercula and 15 conchs.

Etymology. After the name of hunchback Quasimodo .

Diagnosis. The same as for the genus.

Description. Conch orthocone; dorsal side slightly vaulted in lateral view. Cross-section of conch subtriangular with a high keel. W/h index = 1.3, angle of divergence ranging between 15 and 20 degrees. Amblygonal aperture; semicircular ligula provided with one transversally elongated apertural muscle scar. Other scars are positioned on lateral edges, being situated slightly behind the aperture. These scars being elliptical in outline and very distinct on mould. Apical septa probably not developed. Surface sculpture of conch consisting of very fine, almost indistinct growth-lines. Platyclaviculate operculum flat and robust clavicles divided by longitudinal diaphragms in hollow channels. In crosssection triangular cardinal processes opened and broadly diverging. Their anterior and posterior ends almost parallel; their axes lying in one line. Very thick-walled cardinal area sagitally elongated into rounded processes. Several radial channels developed between the outer and inner surfaces of cardinal shield. These channels most probably made the cardinal shield lighter. Distinct paired adductor muscle scars arched and deflected. Sculpture of external opercular surface consists of growth-lines. Several thicker riblets developed near summit of operculum.

Dimensions. Maximum length of adult specimen was 25 mm.

Occurrence. The type species Q. quasimodo sp. nov. is known only from the middle Cambrian of the Skryje– Týřovice Basin at the localities Biskoupky, Buchava and Hradiště.

Figures

FIGURE 4. Quasimolites quasimodo gen. et sp. nov.; middle Cambrian, Buchava Formation, Skryje Member, Paradoxides (Eccaparadoxides) pusillus Zone, Buchava locality. Scale bar = 1 mm. A – I. Quasimolites quasimodo gen. et sp. nov. A. Holotype, NM L 40476, inner surface of operculum. B. Holotype, latex cast of NM L 40476, inner surface of operculum. C. Paratype, NM L 40475, outer surface of operculum, Buchava locality. D. Paratype, latex cast of NM L 40719, apertural part of external mould of venter with distinct muscle scars. E. Holotype, NM L 40476, inner surface of operculum. F. Paratype, NM L 40475, outer surface of operculum. G. Paratype, NM L 40474, frontal view of internal mould of conch. H. Paratype, NM L 40474, lateral view of internal mould of conch. I. Paratype, NM L 40474, dorsal view of internal mould of conch.