Eucrassatella marshalli is a species of bivalve, a marine mollusc in the family Crassatellidae. Fossils of the species date to the Waipipian stage (3.70 million years ago) of the late Pliocene in New Zealand. Based on morphological evidence, the species is likely a descendant of the late Miocene species E. ampla, and is ancestral species to the recent Australian species E. kingicola.
Description
In the original description, Powell described the species as follows:
The holotype of the species has a height of , a length of , and a thickness of for a single valve.
The species can be identified due to being smaller and less massive than E. ampla, by having very rounded posterior, anterior and umbonal regions, and by the species' dorsal margins being distinctly concave due to the impression of the lunule and escutcheon.
Taxonomy
The species was first described by A. W. B. Powell in 1931. Based on morphological evidence, it is likely that the species evolved from E. ampla, a New Zealand fossil species of the late Miocene, and is an ancestral species to the recent Australian species E. kingicola.
The holotype was collected in January 1931 by Powell from west of the Wairoa Stream mouth near Waverley, Taranaki, and is a set of two syntypes, with each valve of similar size coming from two unrelated specimens. It is held in the collections of Auckland War Memorial Museum.
Ecology
The species is one of the most common found in the Waipipian stage strata at its type locality on the coast of South Taranaki near Waverley.
Distribution
This extinct marine species occurs in the late Pliocene Waipipian stage (3.70 million years ago) in New Zealand. Fossils of the species have been found in South Taranaki, and at Māngere in Auckland.
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References