Portal de Periódicos da CAPES

The Cambrian Radiation of Brachiopods

1992; Springer Nature; Linguagem: Inglês

10.1007/978-1-4899-2427-8_12

2452-1639

Leonid E. Popov,

Astro and Planetary Science

Traditionally, Brachiopoda (sensu lato) is regarded as a distinct phylum of lophophorate animals and is divided into two major taxa, Class Inarticulata (or Ecardines) and Class Articulata (or Testicardines). Both taxa are polythetic, but their diagnoses are based mainly on two features: the presence or absence of the articulation of the valves, and an open or blind digestive tract. The known differences between classes are possibly persistent from the beginning of the Ordovician. However, the earliest Cambrian brachiopods display various combinations of unusual morphological features, which were not inherited in further evolution. During the past two decades considerable progress has been made toward understanding the morphology and phylogenetic relationships between major taxa of Cambrian brachiopods, but our knowledge of the initial Cambrian radiation is still incomplete.