Sunday, July 5, 2015

Macropleura macropleura brachiopod from the Kalkberg formation of New York

If I may paraphrase the song "New York, New York" by Gerard Kenny, Macropleura is a brachiopod so nice, they named it twice! Macropleura macropleura is a large brachiopod and hard to mistake for something else in the Kalkberg formation. I've found similar specimens from the Licking Creek formation of  Virginia but there they were silicified. Despite its large size, I've yet to find any whole, articulated specimens. The specimens below both appear to be pedicle valves. They have thick, ovate shells that are wider than long and feature only a few, strong plications. The surface of the shells also features fine striae (lines that extend from the beak) and concentric growth lines.

Specimen #1 - Pedicle valve
Anterior - you can see some of the striae along a plication near the margin of the shell
Profile
Posterior

Specimen #2 - Pedicle valve with more visible striae in the folds between the plications.
Interior views of the pedicle valve. Some matrix needs to be removed yet. A better view of the internal structures can be seen in the specimens I blogged from the Licking Creek formation of  Virginia.



The Kalkberg formation is lower Devonian in age (Lockhovian to Pragian stage). I collected this specimen from a roadcut near Shoharie, NY.

Friday, July 3, 2015

Uncinulus campbellanus brachiopod from the Kalkberg formation of New York

The Rhynchonellida brachiopods are often tough to discern from one another, Especially some of those in the family Uncinulidae. Case in point are these two specimens that I believe are Uncinulus campbellanus (based on Karl Wilson's book "Field Guide to the Devonian Fossils of New York"). Both come from the Kalkberg formation (Devonian, Lockhovian to Pragian stage) and were found in the same area. They have a larger brachial valve than the pedicle valve and feature a sulcus at the margin with a poorly defined ridge on the brachial valve. There are at least 20 rounded plications on both valves which is a key identifier for U. campbellanus. Also, the overall shell, when viewed from above or below, does not as quickly come to a point at the beak like U. pyramidatus does (which was my first guess when I started to ID these specimens).

Specimen #1 - Brachial valve (with some matrix remaining)
Anterior
Pedicle valve
Posterior
Profile

Specimen #2 - Brachial valve
Anterior
Pedicle valve
Posterior
Profile

The Kalkberg formation is lower Devonian in age (Lockhovian to Pragian stage). I collected this specimen from a roadcut near Shoharie, NY.

Wednesday, July 1, 2015

Meristella arcuata brachiopod from the Kalkberg formation of New York

A very common brachiopod from the lower Devonian is Meristella. It is likely the most common brachiopod that I found in the Kalkberg formation of NY when collecting a couple of months ago. The specimens below are Meristella arcuarta and are among the few whole, intact specimens that I found. More often I found isolated, disarticulated valves or they were somewhat crushed even more than the first specimen below.  M. arcuata is a round to oval shaped shell that is longer than wide with both valves being convex. The shell surface is smooth except for occasionally strong concentric growth lines. The pedicle valve curves back to a beak with a  round foramen is found which is where the pedicle muscle extended in life. The pedicle vale features a sulcus that is only really expressed at the margin of the shells.

Specimen #1 - Pedicle valve
Anterior
Brachial valve
Posterior
Profile

Specimen #2 - This is a bit better inflated specimen but there is still some matrix adhering to the surface of the brachial valve.
Anterior
Pedicle valve
Posterior
Profile

Something that is pretty cool are the epibionts that encrust the surface of the shell. It looks like some colonies of the bryozoan Lichenalia maculosa.



The Kalkberg formation is lower Devonian in age (Lockhovian to Pragian stage). I collected this specimen from a roadcut near Shoharie, NY.

I have posted previously about many different species of Meristella like M. atoka from the Haragan Fm. of OklahomaM. arcuata from the Onondaga Fm. of New York, and M. obtusa from the Wenlock Fm. of England.

Monday, June 29, 2015

Trematospira multistriata brachiopod from the Kalkberg formation of New York

I'm going to kick off a series of posts that all feature fossils from the Kalkberg formation of New York with this specimen of Trematospira multistriata. It is a rounded, rectangular shaped shell with both valves showing some convexity. The shell is wider than long. Multiple thick costae decorate the surface of the shell and there is a wide sulcus that is best expressed on the pedicle valve. I base my ID on James Hall's "Paleontology of New York", Vol 3, Pt. 1, pg 209, & Pt 2, pl 28a, fig 5a-f

Brachial valve
Anterior
Pedicle valve
Posterior
Profile


The Kalkberg formation is lower Devonian in age (Lockhovian to Pragian stage). I collected this specimen from a roadcut near Shoharie, NY.

The only other Trematospira species I have posted about is Trematospira camara from the Silurian aged (Shienwoodian stage) Irondequoit limestone near Lockport, NY.

Saturday, June 27, 2015

Phestia rostellata pelecypod from the Ludlowville formation of New York

On a collecting trip in May I found a specimen of the genus Phestia which I had read about but never found myself. Phestia is a very distinctive shell that looks like a giant comma. One end is rounded while the other sweeps away and narrows nearly to a point. Overall the shell has fine, yet distinct, concentric growth lines as the only decoration. According to Karl Wilson's book "Field Guide to the Devonian Fossil of New York", what I found is called Phestia brevirostra. It looks very similar to Nuculana rostellata (from the Arkona shale) and they could be synonyms or, at the least, close cousins.



I did a little more research into the naming of the species and it appears that Hall originally had a similar form listed as Leda rostellata in "Paleontology of New York", Vol 5, Pt. 1, pg 330, pl 47 and had a Leda brevirostris listed as well (pg 329, pl 47). The difference between the two was that L. rostellata has the elongated valves while L. brevirostris is shorter and less curved. I'm not sure at what point the genus was changed to Phestia as Leda is still valid. To add to the confusion, Conrad created the name Nuculana rostellata in 1841 ( T. A. Conrad. 1841. Fifth annual report on the paleontology of the state of New York. New York Geological Survey, Annual Report 5:25-57) but I can't find a copy of that document which means I'm unable to compare the original descriptions or plates to Hall's from the Paleo. of NY.

To help try and clear up the issue, I posted this specimen and one from Arkona to a couple of Facebook groups. I was fortunate to have Gwen Daley respond in the group "The Devonian Period" and Dan O'Dea respond in the group "The Fossil Forum" both pointing me towards a paper called "Devonian Rocks and Lower and Middle Devonian Pelecypods of Guangxi, China and the Traverse Group of Michigan" and more specifically to Section G - "Systematic Paleontology of the Devonian Pelecypods of Guangxi and Michigan" by John Pojeta Jr., Zhang Renjie , and Yang Zuny. Within that section, on pages 64-65, is a discussion that essentially eliminates the use of Nuculana for Paleozoic pelecypods.

"For many years, Paleozoic opisthogyrate nuculaniform shells with fine external ornament were placed in the genus Nuculana (Link) (=Leda Schumacher)(pl. 3, fig. 10), which they closely resemble in shape (pl. 6; pI. 7, figs. 1-3, 12). McAlester (1962) suggested that the name Nuculana is inappropriate for Paleozoic species; in part, this was because Carboniferous species lack the pallial sinus of living forms. McAlester (1969b, p. N237, N239) limited the name Nuculana to Mesozoic and Cenozoic species and indicated that the name Phestia (Chernyshev) is appropriate for Devonian-Lower Triassic nuculanids that are not yoldiaform."
I've reproduced plate 6 from the paper which illustrates specimens of Phestia rostellata from the Hamilton group of both New York (fig 6-7) and Ontatio (fig 8-10).
In summary, I'm naming the fossil above, which I collected from the Windom shale member of the Moscow Formaiton (Devonian, Givetian stage) in Madison County, New York, and those specimens I've collected from the Arkona shale, and previously called Nuculana rostellata, what I feel is the proper name for both: Phestia rostellata (Conrad 1841) .