Tuesday, February 3, 2015

Devonochonetes scitulus brachiopod from the Ludlowville formation

As I mentioned in my last post, Chonetid type brachiopods are tough to get a good ID on unless you have the delicate spines that emerge from the valve hinge line preserved. I was pleased to find one of the shells I'd found from the Geer Rd. locality (Upper Ludlowville formation, Devonian, Givetian stage) was a Longispina mucronata and so went back through my other findings to see if I could find any more. Lucky for me there was another specimen with spines present.

On this chunk of rock are a few stray Chonetid brachiopods but the well preserved specimen in the center right has a spine or two preserved.
A closer view with my camera reveals a single spine on the right side of the shells hinge line that is poking out at an angle.

Like with the Longispina mucronata specimen, I took this one up to my microscope to get a better picture. There is a single well preserved spine and what looks like the base of another just to the left of it. Based on the angle and location of the spine I would say that this specimen is a Devononchonetes scitulus (which has three to six spines extending from the hinge line, at an angle away from the shell), my first truly confirmed specimen of this species!

Specimens, such as these from the Arkona and Widder formations, have a similar shell size and ornamentation, and I've referred to them as D. scitulus, but I've not found any with spines that would confirm my theory.

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