Brachiopods from the Permian Fort Apache Limestone East of Payson

Updated  10/20/17

 Brachiopods are a minor faunal element in the Fort Apache Limestones, nearly 100% were found as Productids and their hordes of tiny spines. Only ONE other brach was found, and it was microscopic in size at a size of 1 mm. No doubt the large amount of mud and silt raining down on the bottom of the Fort Apache Sea made life very difficult for any type of filter feeders. Largely missing as well are corals, crinoids and sponges which also feed by filtering the muddy waters. Only the Productids seemed to be adapted to such conditions.

Both silicified and calcified fossils were found. Some of the silicified fossils were very delicate and had many of the spines still attached when dissolved out of the limestones with muriatic acid. Winters in his monumental GSA memoir 89 identifies the productids as Bellaclathrus spinosus, and the tiny brach as Pseudodielasma sp. Since this is a very generic looking brachiopod, well go with his identification.

 Pseudodielasma sp. top view, pedical valve. This brach is the size of a pinhead and is the only one found after processing over 200 pounds in limestones! 45x
 Pseudodielasma sp. bottom view, brachial valve. Here you can see the opening at the top for the pedicle to emerge for external support on a hard substrate. 45x

 Bellaclathrus spinosus, only about an inch across it is far smaller than the average size of the productids found in the overlying Permian Kaibab formation. This one is calcified on the surface of the limestone found by cracking open large rocks. 2x
 Bellaclathrus spinosus - two specimens. 2x
 Bellaclathrus spinosus - a really nice specimen showing the wings on the sides of the umbo. 2x

 Bellaclathrus spinosus - very flat upper valve that is calcified. 3x

 Bellaclathrus spinosus - Silicified specimen shows some of the spines still attached. 2x

 Bellaclathrus spinosus - top valve seen here attached to basal valve with spines. The valves of brachiopods normally do not separate when they are empty. 2x

 Bellaclathrus spinosus - nice shot of the spines. 2x

 Bellaclathrus spinosus - Silicified specimens show much external detail. But they are hollow and very delicate! Notice the spine coming off the wings. 2x

 Bellaclathrus spinosus - other side. 2x

 Bellaclathrus spinosus - two spines on the valve wings. 3x

 Bellaclathrus spinosus - We found hordes of loose productid spines in the limestones. 7x

 Bellaclathrus spinosus - Close up at 20x of some of the spines. Most are hollow tubes, and never come to a point. In life they are filled with live tissue and the spines grow by adding on to the ends.

 Bellaclathrus spinosus - Two spines on a common base which was once the outermost layers in the productid shell. 20x.

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