Skryjelites auritus gen. et sp. nov. and Quasimolites quasimodo gen. et sp. nov. — two new middle Cambrian hyolithids (? Mollusca) from the Czech Republic
Author
Valent, Martin
Author
Fatka, Oldřich
Author
Szabad, Michal
Author
Micka, Václav
Author
Marek, Ladislav
text
Zootaxa
2015
4007
3
419
426
journal article
10.11646/zootaxa.4007.3.8
566a1607-df5c-4c5f-ba4e-7f1e5f99c772
1175-5326
241042
7BB08011-664C-4437-8A9E-98DB9FD23C32
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.