Anchura biangulata Anderson

Kaim, Andrzej, Jenkins, Robert G., Tanabe, Kazushige & Kiel, Steffen, 2014, Mollusks from late Mesozoic seep deposits, chiefly in California, Zootaxa 3861 (5), pp. 401-440 : 421

Pseudanchura biangulata ( Anderson, 1938)

( Fig. 9A–D )

1938 Anchura biangulata Anderson , n. sp.; Anderson 1938, pl. 9, figs. 4–6.

Description. The best preserved specimen (CAS 73132) is composed of six high-spired whorls. Two earliest are rounded with poorly visible ornamentation spiral riblets while the third whorl bears no ornamentation apart from strong median keel. The aperture and apertural extensions not preserved in the investigated specimens.

Material and occurrence. Two poorly preserved juvenile specimens ( CAS 73132, 73133). Eagle Creek (Late Barremian, Early Cretaceous).

Remarks. P. biangulata has been reported from a couple of localities in the Ono area by Anderson (1938) and it remains uncertain whether they were seep locations or "normal" deep water sediments. Most likely the association of P. biangulata with seep carbonates is fortuitous as aporrhaids are gastropods typical for soft bottom marine environments during Mesozoic times and they have been found at various Jurassic to Paleocene seep deposits ( Kaim et al. 2008b; Kiel et al. 2010, 2013; Agirrezabala et al. 2013).

Figures

FIGURE 9. A – D. Pseudanchura biangulata (Anderson, 1938) from Late Barremian (Early Cretaceous) seep site at Eagle Creek, Shasta County, California, USA. A. CAS 73132. B – D. Juvenile CAS 73133. E – F. Diaphana sp. from? Valanginian (Early Cretaceous) seep carbonates at West Berryessa, Napa County, California, USA; GZG. INV. 84994.