A new species of Hoploscaphites (Ammonoidea, Ancyloceratina) from cold methane seeps in the Upper Cretaceous of the U.S. Western Interior

Related Titles

Series: American Museum novitates, no. 3781

By

Landman, Neil H.

Kennedy, W. J. (William James)
Cobban, William Aubrey, 1916-
Larson, Neal L.
Jorgensen, Steven D.

Type

Book

Material

Published material

Publication info

New York, NY, American Museum of Natural History, [2013], ©2013

Notes

Caption title.

"September 23, 2013."

We describe Hoploscaphites gilberti, n. sp. (Ammonoidea: Ancyloceratina), from the Upper Cretaceous (middle-upper Campanian) Pierre Shale spanning the zones of Baculites scotti and Didymoceras nebrascense in Colorado, Wyoming, Montana, and South Dakota. This species is strongly dimorphic and is characterized by a compressed whorl section, with a rounded to elongate outline in lateral view. The apertural angle is approximately 50° in macroconchs. The body chamber is ornamented with fine flexuous ribs, umbilicolateral bullae, and ventrolateral tubercles. Hoploscaphites gilberti, n. sp., most closely resembles H. gilli Cobban and Jeletzky, 1965, but differs from this species in several important features: (1) the flanks of the body chamber are nearly subparallel rather than steeply convergent toward the venter, (2) the ventrolateral tubercles are larger and more numerous, and (3) the ribs are more widely spaced. Hoploscaphites gilberti, n. sp., is abundant at "tepee buttes" in the Pierre Shale, which are now interpreted as cold methane seeps.

Subjects

Ammonoidea , Cretaceous , Hoploscaphites gilberti , Mollusks, Fossil , Paleontology , Pierre Shale , West (U.S.)

Call Number

QL1 .A436 no.3781 2013

Language

English

Identifiers

OCLC: 858805212