Two gastropod steinkerns from the Lime Creek formation of Iowa

I found two gastropod steinkerns in my collection of Lime Creek Formation fossils from Rockford fossil Park in Iowa. They caught my attention as I was sorting the fossils I have from there to find duplicates I could send to a friend in Germany.

The first specimen is a Bellerophon sp. steinkern. Gastropods of this genera generally have a wide flaring opening to the body chamber and the shell whorls imbricate (directly overlap) upon themselves. The flared portion of the shell is missing on this steinkern but the whorls are imbricated.

Anterior view

Left side profile

Posterior view

Dorsal view

Ventral view

The other steinkern specimen is a gastropod called Floydia sp. whose whorls are not imbricated but appear stacked on top of each other. As this is an internal steinkern it is impossible to tell if the genera is correct much less determine the species.

Left profile

Anterior view

Dorsal view

Ventral view

Both of these specimens come form the late Devonian aged Lime Creek formation (Fransian stage).

Theodossia hungerfordi brachiopod from Iowa

Another brachiopod from the Lime Creek Formation is Theodossia hungerfordi. From what info I can find (primarily Paleodb.org) Theodossia is a genus that is confined to the late Fransian stage of the Devonian. This is a fairly common species in the Lime Creek Fm. as is evidenced by the many specimens seen in auctions and at fossil shows.

Brachial valve (with a little dent in it)

Anterior

Pedicle valve

Posterior

Profile

A sampling of different sized shells

The above specimen came from the Lime Creek Formation exposed in an old quarry that has been converted into a tourist park called the Fossil and Prairie Park Preserve near Rockford, Iowa.

Riqauxia orestes brachiopod from Iowa

Here is another species of Brachiopod I picked up from E-bay. The label that came with them said they were "Spirifer whitneyi" from the Lime Creek Formation (U. Devonian)near Rockford, Iowa. However a quick perusal of the "Index Fossils of North America" does not show that species as occurring in the Devonian. My friend Nathan recently posted a series of pictures of Brachiopods that he found in Rockford, Iowa and were IDed by an expert. About half way through the list I found Riqauxia orestes that seemed to match the specimen I had:

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

A selection of specimens of different sizes.

The above specimens came from the Cerro Gordo member of the Lime Creek Formation, which is Upper Devonian (Fransian) in age.

Hystricina trulla brachiopod from Independence, Iowa

Hystricina trulla is another wavy/spiny surfaced brachiopod like Spinatrypa. I liken it to Pseudoatrypa because it has a similarly deep, convex brachial valve.

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

This specimen is still partially embedded in the matrix.

The specimens shown above came from the Cedar Valley formation (Devonian, Givetian stage) near Independence, Iowa. I purchased both specimens from this seller on E-bay.

Spinatrypa rockfordensis brachiopod from Rockford, Iowa

Spinatrypa is a species I didn't know existed in the Devonian until I found my first specimens in the Windom Shale at the Penn Dixie center in Blasdell, NY.  Maybe the Mahantango formation was too muddy for them to survive. The specimens below come from the Lime Creek Formation (U. Devonian) near Rockford, Iowa.

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

A second specimen... Brachial valve

Anterior

Pedicle valve (note the partial spine preserved in the attached matrix)

Posterior

Profile

A sampling of several specimens in various growth stages.

My friend Nathan recently posted a series of pictures of Brachiopods that he found in Rockford, Iowa and were IDed by an expert. He shows two different species of Spinatrypa: S. planosulcata and S. rockfordensis. I believe that the specimens I have could all be classified at S. rockfordensis.

The above specimens came from the Cerro Gordo member of the Lime Creek Formation, which is Upper Devonian (Fransian) in age. Thanks to Nathan for some of the specimens. Others I have picked up in auctions on E-bay.

Strophonella reversa from Iowa

These next specimens, which come from Rockford, Iowa, I purchased from a seller on E-bay. They are Strophonella reversa and come from the Lime Creek formation.Compared to other members of the Strophomenida order, these are relatively robust fossils which display the typical curvature of the Pedicle valve, but the Brachial valve is not as convex.

Pedicle valve

Anterior

Brachial valve

Posterior

Profile

Four specimens side by side to show the variation within the species.

The above specimens came from the Cerro Gordo member of the Lime Creek Formation, which is Upper Devonian (Fransian) in age.

Douvillina arcuata from Iowa

In line with my previous post regarding Protodouvillina, here are some examples from the upper Devonian of Iowa.

Pedicle valve

Anterior

Interior of Pedicle valve

Posterior

Profile

Here is a second specimen

Pedicle valve

Anterior

Interior of the Pedicle valve

Posterior

Profile

Four different specimens to show the variation within the species.

A Thank You goes out to my friend Nathan for giving me these specimens that he collected from the Cerro Gordo Member of the Lime Creek Formation (Fransian stage of the Devonian) near Rockford, Iowa.