New species of extinct vampire-squid-like cephalopod is the first of its
kind with 10 functional arms
Description of exceptionally preserved fossil pushes back age of
Vampyropoda by nearly 82 million years

Date:
March 8, 2022
Source:
American Museum of Natural History
Summary:
New research shows that the oldest ancestors of the group of
animals that includes octopuses and vampire squids had not
eight but 10 arms. The study, which describes a new species of
vampyropod based on a 328- million-year-old fossil that had not
been previously described, pushes back the age of the group by
nearly 82 million years.



FULL STORY ==========================================================================
New research led by scientists at the American Museum of Natural
History and Yale shows that the oldest ancestors of the group of
animals that includes octopuses and vampire squids had not eight but 10
arms. The study, which describes a new species of vampyropod based on
a 328-million-year-old fossil that had not been previously described,
pushes back the age of the group by nearly 82 million years. The details
are published today in the journal Nature Communications.


========================================================================== "This is the first and only known vampyropod to possess 10 functional appendages," said lead author Christopher Whalen, a postdoctoral
researcher in the Museum's Division of Paleontology and a National
Science Foundation postdoctoral fellow in Yale's Department of Earth & Planetary Sciences.

Vampyropods are soft-bodied cephalopods typically characterized by
eight arms and an internalized chitinous shell or fin supports. Because
they lack hard structures, Vampyropoda are not well represented in the
fossil record. The new study is based on an exceptionally well-preserved vampyropod fossil from the collections of the Royal Ontario Museum
(ROM). Originally discovered in what is now Montana and donated to ROM
in 1988.

Whalen and coauthor Neil Landman, a curator emeritusin the Museum's
Division of Paleontology, identified the fossil specimen as a completely
new genus and species that dates to about 328 million years old, making it
the oldest known vampyropod and extending the fossil record of the group
by about 82 million years. In the new study, they also describe its 10
arms -- all with preserved suckers -- corroborating previous scientific arguments that the common ancestor of vampyropods had 10 arms as well.

"The arm count is one of the defining characteristics separating the
10-armed squid and cuttlefish line (Decabrachia) from the eight armed
octopus and vampire squid line (Vampyropoda). We have long understood
that octopuses achieve the eight arm count through elimination of the
two filaments of vampire squid, and that these filaments are vestigial
arms," said Whalen. "However, all previously reported fossil vampyropods preserving the appendages only have 8 arms, so this fossil is arguably
the first confirmation of the idea that all cephalopods ancestrally
possessed ten arms." Two of the cephalopod's arms appear to have been elongated relative to the other eight arms, and its torpedo-shaped body
is reminiscent of today's squids.

The fossil was given the name Syllipsimopodi bideni. The genus name is
derived from the Greek word "sylli'psimos" for "prehensile" and "po'di"
for "foot" - - because this is the oldest known cephalopod to develop
suckers, allowing the arms, which are modifications of the molluscan
foot, to better grasp prey and other objects. The species name is to
honor the recently inaugurated (at the time of paper submission) 46th
President of the United States, Joseph R. Biden.

"Syllipsimopodi may have filled a niche more similar to extant squids,
a midlevel aquatic predator," said Landman. "It is not inconceivable that
it might have used its sucker-laden arms to pry small ammonoids out of
their shells or ventured more inshore to prey on brachiopods, bivalves,
or other shelled marine animals." Based on the age, characters, and phylogenetic position, the fossil challenges the predominant arguments
for vampyropod origins, and the authors propose a new model for coleoid (internally shelled cephalopod) evolution.

This study was supported in part by the U.S. National Science
Foundation Postdoctoral Fellowship in Biology Program (#2010822) and the Paleontological Society Student Research Grants Elis L. Yochelson Award.


========================================================================== Story Source: Materials provided by
American_Museum_of_Natural_History. Note: Content may be edited for
style and length.


========================================================================== Related Multimedia:
*
Image_of_a_well-preserved_vampyropod_fossil_from_the_collections_of_the
Royal_Ontario_Museum_that_the_new_study_is_based_on ========================================================================== Journal Reference:
1. Christopher D. Whalen, Neil H. Landman. Fossil coleoid cephalopod
from
the Mississippian Bear Gulch Lagersta"tte sheds light on early
vampyropod evolution. Nature Communications, Mar. 8, 2022; DOI:
10.1038/s41467-022- 28333-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220308115650.htm

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