What is the difference between articulate and inarticulate brachiopods?
Articulate brachiopods have toothed hinges and simple opening and closing muscles, while inarticulate brachiopods have untoothed hinges and a more complex system of muscles used to keep the two valves aligned. The word “brachiopod” is formed from the Ancient Greek words brachion (“arm”) and podos (“foot”).
What is the meaning of brachiopod?
: any of a phylum (Brachiopoda) of marine invertebrates with bivalve shells within which is a pair of arms bearing tentacles by which a current of water is made to bring microscopic food to the mouth.
How can you identify a brachiopod?
Other shell features are useful for identifying brachiopods. A sulcus (a groove-like depression) is present on many brachiopod shells, and a fold (a raised ridge) can be found on the opposite valve. Costae are elevated ribs on the shell. Growth lines are concentric rings representing successive periods of growth.
Where do articulate brachiopods live?
Articulate brachiopods also have adjuster muscles to move the pedicle. Brachiopods are benthic marine invertebrates that inhabit both deep water and shallow environments. However, the majority of brachiopods lived and still live in shallow water and intertidal zones.
What kind of teeth do brachiopods have?
Rhynchonelliform (articulate) brachiopods. Rhynchonelliform brachiopods have shells made calcium carbonate and interlocking pegs (teeth) and sockets that form a hinge between the valves. The teeth are in one valve (the pedicle or ventral valve) and the sockets are in the other (the brachial or dorsal valve).
How are the valves of a brachiopod held together?
Articulate (“jointed”) brachiopods have a tooth and socket arrangement by which the pedicle and brachial valves hinge, locking the valves against lateral displacement. Inarticulate brachiopods have no matching teeth and sockets; their valves are held together only by muscles.
How did the Brachiopoda get its name articulata?
The name was first applied to this major group of brachiopods by Huxley in 1869, ten years prior to Zittel choosing the same name in 1879 for modern crinoids. The Articulata has been replaced by the subphylum Rhynchonelliformea which except for taxonomic rank and revision of some taxa within, is essentially synonymous.
How are brachiopods anchored to the sea floor?
Many species were anchored to the sea floor by a muscular stalk (pedicle) which emerged through a hole in the pedicle valve (pedicle opening). Exterior. Modern lingulate brachiopods have a shell of two oval, flattened valves made of calcium phosphate. Hinge teeth and sockets are absent.
