Molluscan Research 25(1):
9-13; published 22 April 2005
Copyright © The
Malacological Society of Australasia
A new species of Calliotropis
(Mollusca: Gastropoda:
Vetigastropoda: Trochidae: Eucyclinae)
from the Eocene of Antarctica
JEFFREY D. STILWELL
School of Geosciences, Monash University, Clayton VIC 3800,
Australia and Centre for
Evolutionary Research, Australian Museum, 6 College Street, Sydney,
NSW 2000
Email: Jeffrey.Stilwell@sci.monash.edu.au
Abstract
Trochid gastropods represent an
important, diverse family in the Eocene fossil record of Antarctica with no
fewer than eight recorded species, one newly
described herein. The discovery of Calliotropis
antarchais n. sp. (Eucyclinae) in Telm5
(Unit V) of the La Meseta Formation
(mid-Eocene Epoch, ca. 45-50 Ma) on Seymour Island, Antarctica Peninsula,
marks not only the sole occurrence of this
group in the Antarctic fossil record, but further displays the pronounced
plasticity of form typical in extant taxa.
The new species, an inferred deposit feeder, inhabited very shallow,
subtidal waters in sandy facies and is closely allied
to congeneric taxa, extant in deep waters surrounding the Antarctic
continent. Another
trochid genus that makes its first appearance
in the Antarctic Eocene fossil record (and extending to the Recent), Calliotropis
is otherwise known from the Pale-ocene
(Danian to Thanetian) of Denmark and Australia
only, latest Eocene of New Zealand and Early Oligocene of Germany, disjunct
distributions in New Zealand and Europe during the Neogene (earliest Miocene
to Pliocene), and Quaternary (Pleis-tocene to
Recent) globally. Calliotropis represents
another group that displays marked high-latitude heterochroneity in the
shal-low marine Antarctic Eocene record,
disappearing in preserved Tertiary deposits and reappearing with a
relatively high diversity in Recent
deep-water environments.
Full article (PDF;
340 KB)
|
|
