These next two, giant brachiopod shells are Linoproductus sp. from the early Permian aged (Asselian stage to Sakmarian stage of the ICS, Wolfcampian stage in US stratigraphy) sediments of Callahan County, Texas. This genus is known for having some of the largest shells for brachiopods from the period. The pedicle valve is very convex and the brachial valve startes our flat but becomes concave as the animal got older. The margins of the two valves are often turned 90 degrees from the hinge and (at least in the two specimens I am blogging about today) become very elongated. The surface of both valves are marked with fine striations that are slightly wavy. Occasional spines are present but appear to not be in any planned arrangement.
Specimen #1 - Pedicle valve (note the grooves and marks in the shell which may be indicative of a boring sponge called Clionolithes sp.)
Specimen #2 - Pedicle valve
These specimens come from rocks near Putnam, Texas in Callahan County.