Rafinesquinidae Indet. (1)

[Gen. et sp. indet.]

An Ordovician-Silurian specimen from Pleistocene sediments of Poland. What genus/species is this?

Edited January 6, 2015 by Gen. et sp. indet.

[Herb]

If you are referring to the one at the top it looks like Leptanea sp. but hard to tell.

[izak_]

If you are referring to the one at the top it looks like Leptanea sp. but hard to tell.

Agreed.

[FossilDAWG]

Why are you certain this is a rafinesquinid? The style of ribs and the fairly prominent growth lines are more suggestive of an atrypid to me. At any rate the specimen is too incomplete for a de novo diagnosis. You can see nothing of the internal structures, beak area, or hinge. The only way to generate a somewhat confident ID on a specimen like this is to 1) know what rock formation it came out of, 2) look up the published literature on the brachiopod fauna from that formation, and 3) try to match your specimen to species known to occur in the formation.

Don

[ZiggieCie]

Here are two Leptiania of mine from two different ages, and localities. First is Leptaena rhomboidalis from southern Indiana, at the famous Waldron Quarry. The second one is from north central Ohio, USA, 2 miles from my home, at a new housing development construction area.

The first one is from the Waldron shale, a blue-gray shale of middle Silurian (Niagaran) age, about 420 million years old. There are many references on the Waldron Shale Stratigraphy.

The second one is from down the street from my home. The Strongsville member between the upper Meadville shale and lower Sharpsville member. Upper Mississippian, Kinderhook age, apx. 330 million years old. No name, yet.

[Gen. et sp. indet.]

Thank you for your responses, ideas, and photos!

---

FossilDAWG:

"Why are you certain this is a rafinesquinid?"

I went through many erratic boulders in mine area, and this is just one example of "Leptaena", but as there are some other, less often cited genera, I used the more general rafinesquinid name. Also, I didn't want to suggest anything.

"The only way to generate a somewhat confident ID on a specimen like this is to..."

Well, as I said, it is an erratic boulder, so none of the following applies.

---

I quess then, this one must just be left as unidentifable.

[Herb]

my "guess" is based on the age, the sort of "wing" on the right side, and what look like (to me) as folds running across the plications. Still a SWAG at best