Bizarre Giant Aegirocassis benmoulae Filter-Feeding Anomalocaridid

A from the time of the Great Ordovician Radiation

Aegirocassis benmoulae

Phylum Arthropoda, Order Radiodonta, Family Hurdiidae

Geological Time: Lower Ordovician

Size: Fossil is 90 mm long by 20 mm wide at tip on a 110 mm by 105 mm matrix.

Fossil Site: Upper Fezouata Formation, Zagora, Morocco

Code: 16124

Price: Sold


Aegirocassis benmoulae Filter-Feeding AnomalocarididDescription: This fossil for a time was somewhat problematic Photos were sent to a few individuals and tentative identifications ranging from the jaw of a placodont fish to some sort of an arthropod appendage were offered. Fortunately we made contact with one of the authors of a recent paper on the gigantic filter-feeding anomalocaridid Aegirocassis art Aegirocassis. He graciously told us that it is a ventral spine of the frontal appendage of this 2 meter long arthropod. Fine filtering fibers would have been attached which are sometimes found independently. Obviously Aegirocassis took a different route to finding food, choosing to strain plankton from the sea rather than being a pursuit predator like Anomalocaris. He also graciously identified the associated waffle-like graptolites as Araenograptus murrayi. Examples can be found on both sides of the matrix. I have included a drawing with the structure discussed here circled for easy identification.

Fossil Sales Information

click fossil pictures to enlarge


Fossil Mall Navigation:
l Home l Fossils for Sale Map l Museum and Rare Fossils l How to Buy Fossils l

Navigate by Fossil Category:
l Trilobites
l Ammonites l Fish Fossils l Invertebrate Fossils l
l Crinoids and Echinoderms l Insect Fossils l Dinosaur and Reptile Fossils l
l Cambrian Explosion Fossils l Plant Fossils l Stromatolites l
l Vertebrate Fossils l Fossil Amber l Trace & Ichnofossils l

l Fossils and Paleotological Science Information l