Saturday, May 1, 2010

Mucrospirifer mucronatus Brachiopod

Pictures of a sampling of small brachiopods (1.5-3.0 cm wide) found in the Jeffersonville Limestone (Devonian Period). Using the Fossils of Ohio book and Index Fossils of North America this brachiopod is a Mucrospirifer mucronatus. The Ohio book says they are found in the Columbus Limestone which I think is similar to the Jeffersonville Limestone this was found in. Looking at Nettleroth's book Kentucky Fossil Shells (1889) this brachiopod seems to closely match images on Plate XII figures 14-15 of Spirifera arctisegmenta (1889 name) or today's Spirifer arctisegmenta (Hall).

Another document I have entitled Middle Devonian Type Jeffersonville Limestone at the Falls of the Ohio by James E. Conkin, Barbara Conkin, and Larry Steinrock on page 8, figure 5 labeled Diagnostic fossils of the Jeffersonville Limestone shows it as "Spirifer duodenarius" in the Paraspirifer acuminatus Zone.

So confusing but all the names seem to have spirifer in them.

All brachiopods found in Clark County, Indiana.


Shamalama said...

Are those all of the same fossil or different specimens? The fifth picture seems to show an enlarged inter-area between the Hinge and Beak. That could make it a Platyrachella or other species beside Mucrospirifer.

Fossil Detective said...

Some are different. The images are of 4 fossils. I was wondering if the one might be different. Pictures 4 & 5 are of the same brachiopod and it is taller that all the other ones in the group.

The Index Fossils of North America lists the Playrachella oweni (Hall) as found in Indiana & Kentucky in the Middle Devonian.