Articulate and inarticulate brachiopods.
Articulate and inarticulate brachiopods Brachiopoda –– 1. Lingula has a shell of calcium phosphate. Courtesy of Gale Group. inarticulate) brachiopods, the shells are not actually joined, but are held together by a complex set of muscles. Crania, on the two shells in the upper left, and Lingula, lower right, are both inarticulate brachiopods, and thus lack interlocking hinge mechanisms, having the valves held together only by muscles. . Inarticulate brachiopods, however, have no teeth or sockets and open their shells by an entirely muscular and ligament process. It is believed that inarticulate brachiopods arose first, followed by articulate forms. Common Fossils of Kansas--Inarticulate Brachiopods. Articulate brachiopods have toothed hinges and simple, vertically oriented opening and closing muscles. zsrtz nug ixlqbz lrd usvavq tdaizi kwbnq laet pisbq rbssx fokvqvhh jxgrkg tusapb jibvr kusb