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Brachiopod. Brachiopods (/ ˈbrækioʊˌpɒd /), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection.
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.
Palaeontology portal; Rhynchonella is an extinct genus of brachiopod known from the Late Jurassic to the Early Cretaceous (Valanginian, possibly Barremian). [1] Formerly [2] this genus was understood much more widely (more or less an equivalent of the Rhynchonellida order in the present-day taxonomy) and less critical sources still list species of Rhynchonella from the Ordovician to the Eocene.
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]
Strophomenida is an extinct order of articulate brachiopods which lived from the lower Ordovician period to the mid Carboniferous period. [2] Strophomenida is part of the extinct class Strophomenata, and was the largest known order of brachiopods, encompassing over 400 genera [citation needed].
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]
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.
The trilobite body is divided into three major sections (tagmata): 1 – cephalon; 2 – thorax; 3 – pygidium. Trilobites are so named for the three longitudinal lobes: 4 – right pleural lobe; 5 – axial lobe; 6 – left pleural lobe; the antennae and legs are not shown in these diagrams.