Life Beyond the Permian—Mesozoic-Cenozoic Brachiopod Paleobiogeography, Paleoecology, and Evolution

Abstract

The main focus here is the paleobiogeography and paleoecology of Mesozoic-Cenozoic Brachiopoda, mostly the forms referred to as articulated brachiopods. These are the forms I have worked on primarily for the past two decades. To put these creatures in context some attention should be paid to their evolutionary developments during this time (Fig. 1). The articulated brachiopods that continued into the Mesozoic from the Paleozoic are the rhynchonellides (internally with two processes or prongs, crura, to support the lophophore, Fig. 2.1; examples of external morphology shown in Figs. 3.1–3.5, 4.1); the terebratulides with a brachidium in the form of a loop to support the lophophore (“short-looped” in the Terebratulidina, Figs. 2.2, 2.3, 3.6–3.8, 4.2–4.5; “long-looped” in the Terebratellidina, Figs. 2.4, 2.5, 3.9–3.13); and two forms with a spiral lophophore support, the athyridides and spiriferides (these latter two both become extinct during the Mesozoic; Figs. 2.6, 2.7, 3.14–3.16). The thecideides are micromorphic, cryptic, articulated brachiopods (Fig. 3.17) that have much-debated origins (Baker, 1990; Jaecks, 2000).