Search results
Results From The WOW.Com Content Network
Evolution of brachiopods. The origin of the brachiopods is uncertain; they either arose from reduction of a multi-plated tubular organism, or from the folding of a slug-like organism with a protective shell on either end. Since their Cambrian origin, the phylum rose to a Palaeozoic dominance, but dwindled during the Mesozoic.
This "brachiopod fold" hypothesis suggests that brachiopods evolved from an ancestor similar to Halkieria, [26] a slug-like animal with "chain mail" on its back and a shell at the front and rear end. [53] The hypothesis proposes that the first brachiopod converted its shells into a pair of valves by folding the rear part of its body under its ...
List of living brachiopod species. The following is a taxonomy of extant (living) Brachiopoda by Emig, Bitner & Álvarez (2019). There are over 400 living species and over 120 living genera of brachiopods classified within 3 classes and 5 orders, listed below. Extinct groups are not listed. [1]
L. waikatoensis Pen, 1930. Synonyms. Ligula, Ligularius, Lingularius, Pharetra. Lingula is a genus of brachiopods within the class Lingulata. Lingula or forms very close in appearance have existed possibly since the Cambrian. Like its relatives, it has two unadorned organo-phosphatic valves and a long fleshy stalk.
Spiriferida is an order of extinct articulate brachiopod fossils which are known for their long hinge-line, which is often the widest part of the shell. In some genera (e.g. Mucrospirifer) it is greatly elongated, giving them a wing-like appearance. They often have a deep fold down the center of the shell. The feature that gives the spiriferids ...
List of brachiopod genera. This is a list of brachiopod genera which includes both extinct (fossil) forms [1] and extant (living) genera (bolded). [2] Names are according to the conventions of the International Code of Zoological Nomenclature.
Orthida is an extinct order of brachiopods which appeared during the Early Cambrian period and became very diverse by the Ordovician, living in shallow-shelf seas. Orthids are the oldest member of the subphylum Rhynchonelliformea (Articulate Brachiopods), and is the order from which all other brachiopods of this group stem. [1]
Mucrospirifer is a genus of extinct brachiopods in the class Rhynchonellata (Articulata) and the order Spiriferida. They are sometimes known as "butterfly shells". [2] Like other brachiopods, they were filter feeders. These fossils occur mainly in Middle Devonian strata [2] and appear to occur around the world, except in Australia and ...