[MISSISSIPPIAN] BRACHIOPODS
RHIPODOMELLA × 1 DICTYOCLOSTUS × 1 CAMAROTOECHIA × 1
Fig. 14. Lingula, a typical Recent inarticulate [brachiopod] showing extended pedicle.
Pedicle [Valve]
CLASS ARTICULATA.—
Articulate brachiopods have a well-defined [hinge-line] ([fig. 13]a). One [valve] has well-developed teeth which articulate with sockets in the opposing valve, and there is a well-developed muscle [system] which aids in opening and closing the shell. Articulate brachiopods are characterized by [calcareous] shells which are typically of unequal size and a wide [variety] of shapes (Pls. [18], [19]). The class has been divided into several orders which have been established primarily on the nature of the pedicle [foramen] and the nature of shell growth.
Articulate brachiopods range from Lower [Cambrian] to Recent in age and are particularly abundant in certain [Pennsylvanian] formations of north-central and Trans-Pecos Texas. They are also present in certain other [fossiliferous] strata of [Paleozoic] age but are less abundant and not as well preserved. The only [Cretaceous] [brachiopod] that is found in large numbers is Kingena wacoensis (Roemer) ([fig. 15]), which is particularly abundant in certain formations in the upper part of the Comanche [series].
