Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Thursday, January 24, 2013
Cleiothyridina lata brachiopod from Alberta, Canada
Here is an oddball brachiopod I've had in my collection for a while but didn't really know much about. The label that came with it listed Unispirifer from the Banff Formation in Western Alberta. A quick search on Paleodb.org found it hailed from the lower Carboniferous (Mississippian, Tournasian stage). It's a bit rough but the pedicle valve shows a little detail still. Update 01/27/13: Sharp eyed reader Howard pointed out that this is more likely Cleiothyridina lata, not an Unisprifer.
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
Dave--
ReplyDeleteThis one caught my eye, as I live in Calgary and I'm very familiar with the Banff Fm. brachiopods. I'm afraid this specimen has been misidentified, as it looks nothing like any of the Unispirifers that occur in the Banff.
The standard reference on Banff brachiopods is:
Carter. J.L. 1987. Lower Carboniferous brachiopods from the Banff Formation of western Alberta. Geological Survey of Canada, Bulletin 378, 183 pp.
Carter describes and illustrates three species of Unispirifer from the Banff Fm. U. minnewankensis is a small, "typical spirifer-shaped" brach: wing-shaped, with pointed extremities, and strong, radial ribbing. U. rundlensis is very elongate with broad "wings" and fine radial ribbing: some specimens are dead-ringers for the Devonian Mucrospirifer thedfordensis from Hungry Hollow, ON, that you're more familiar with. U. greenockensis more closely approaches the shape of your specimen, but it still has distinct, pointed "wings", strong radial ribbing and a much shallower fold-and-sulcus than your specimen.
Your specimen is missing most if not all of the outer shell surface, so it's probably impossible to be certain of its identity, but assuming it really does come from the Banff Fm., its shape and size more closely resemble Cleiothyridina lata Shimer than anything else from this formation.
Cheers,
--Howard
Howard, Thank you very much for your input on this fossil. It can be frustrating when one gets a fossil with little to no information with it. Even more so when that info is wrong. I think I received this as a freebie from a dealer and it just sat in a box until I decided to photograph it.
Delete-Dave