Metacoceras is a genus of cephalopod found in the Upper Carboniferous until its extinction in the Permian. First described by Hyatt in 1883, the genus includes several distinct species that have been found in North America, Europe, and Asia.

Alpheus Hyatt’s original description of Metacoceras

Metacoceras, nobis, includes Silurian and Carboniferous species with broad, ventral, lateral, and dorsal lobes but no annular lobes. Siphon near the ventrum or central. Whorls quadrate, sides with one row of nodes along the external border, umbilical shoulders smooth but gibbous, the type has this part of the whorls elevated into a ridge. The forms are evidently transitions from the genus Plectoceras to Mojsvaroceras. Type, Meta. (Discus) Sangamonense, M. et W., Geol. Surv. 111., Vol. 2, pi. 29. Meta. (Lit.) occidentale, sp. Hall from Trenton of 111. Am. Mus. N. Y., is the transitional type from Plectoceras to Metacoceras.

Metacoceras Temporal Range

Map of Pangaea during the P-T Extinction Event by Wikipedia user LucasVB
Pangaea at the time of the P-T Extinction Event
– Wikipedia user LucasVB

The genus is found from around the mid-Pennsylvanian Carboniferous through nearly the entirety of the Permian. The Permian / Triassic (P-T) mass extinction event wiped it and 96 percent of all marine species from planet Earth. This was a time where Pangaea was in a very solid form. Parks Township, if laid upon this map would be nearly deeply embedded within the shorelines of the Panthalassic Ocean. This ocean was a super-ocean that surrounded Pangaea. Local specimens that we collect today were long expired and locked in limestone. The genus persisted in the seas until the extinction event.

While it is mostly known why marine creatures died during this event, it’s still up for debate. One theory is that too much CO2 in the air was a large factor, as it is 28 more times soluble in water than is oxygen. The CO2 can disrupt basic life functions and make ocean waters more acidic.

The temporal range of the genus Metacoceras, 314.6 to 252.3 million years ago.

Cephalopod Shell Morphology.

There are many important dimensions and physical callouts to use when describing a fossil cephalopod specimen. The illustration below points out common phrases used when describing. This is for coiled cephalopod shells.

Cephalopod Shell Morphology

Metacoceras Specimens

CG-0004Metacoceras I
CG-0005Metacoceras II
CG-0021Metacoceras III
CG-0024Metacoceras IV
CG-0037Metacoceras V
CG-0042Metacoceras VI
CG-0065
CG-0071A Complete Metacoceras
CG-0075Metacoceras Group
CG-0076
CG-0077
CG-0078
CG-0079
CG-0080
CG-0082Polished 1/2 whorl
CG-0083Cut specimen
CG-0092Metacoceras Specimen
CG-0122
CG-0123
CG-0124
CG-0125

Photos of Metacoceras Specimens

These are photos of Metacoceras specimens found in our Fossil catalog. There are at least one identified species, and two distinct species types.

References