Mollusks from late Mesozoic seep deposits, chiefly in California
Author
Kaim, Andrzej
Author
Jenkins, Robert G.
Author
Tanabe, Kazushige
Author
Kiel, Steffen
text
Zootaxa
2014
3861
5
401
440
journal article
10.11646/zootaxa.3861.5.1
0b368704-d9cc-4a82-8248-bc4c06dcf781
1175-5326
252462
E62DB6C3-0C5F-4898-99C4-1BEC70DD1734
Neocrassina californica
(
Stanton, 1895
)
(
Fig. 15
)
Astarte californica
Stanton, 1895
, p. 57, pl. 6, figs. 19–21.
Supplementary description.
Escutcheon symmetrical, broad lanceolate, bounded by sharp ridge, commarginal sculpture of shell surface continues only faintly inside the escutcheon; lunule deep, lenticular, bounded by ridge; anterior adductor muscle scar oval in outline and most deeply impressed posteriorly; two thick cardinal teeth that radiate inward in left valve, one thick cardinal in right valve; posterior tooth elongate and well developed.
FIGURE 15.
Neocrassina
californica
(Stanton, 1895)
from Cretaceous seep carbonates in California.
A, B.
Specimen showing sharply delineated escutcheon, from the Valanginian of Bear Creek (GZG.INV.85004).
C, D.
Specimens showing lunule, from Bear Creek (GZG.INV.85005).
E.
Interior of a left valve, from Bear Creek (GZG.INV.85006).
F.
Type specimen from CFCC (USNM 23053), note stronger ribbing than on the specimens from Bear Creek.
Material and occurrence.
4 specimens
from Bear Creek (Valanginian, Early Cretaceous); Stanton’s (1895)
type
material from Cold Fork of Cottonwood Creek (Albian, Early Cretaceous) was also seen (
USNM
23053).
Remarks.
Our four specimens from the Bear Creek site reach only
17 mm
in length and are thus smaller than Stanton’s (1895)
type
specimens from CFCC. No additional specimens were found at CFCC during a visit in 2011. The genus
Neocrassina
was widely distributed during the Jurassic when it preferred fine to medium grained sands and thus middle shelf settings (
Gardner & Campbell 2002
). Most Cretaceous records appear to be restricted to the northern Hemisphere [Siberia (
Saks 1975
) and northern
Japan
(
Hayami 1975
)]; although
Chavan (1969)
reports a range into the Turonian.