Acrotretidae
Acrotretidae is a family of brachiopods, the type family of the Acrotretida Acrotretida is an extinct order of linguliform brachiopods in the class Lingulata. They lived from the Lower Cambrian to the Middle Devonian, with their peak diversity from the Middle Cambrian to the Ordovician. Acrotretida contains the sole ... order. References Lingulata {{paleo-protostome-stub ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Acrotretida
Acrotretida is an extinct order of linguliform brachiopods in the class Lingulata. They lived from the Lower Cambrian to the Middle Devonian, with their peak diversity from the Middle Cambrian to the Ordovician. Acrotretida contains the sole superfamily Acrotretoidea. Many acrotretides have a tall and conical ventral valve with a pedicle opening at the apex, while the dorsal valve was convex to a much lesser degree. Based on preserved muscle scars, the lateral muscles are shifted back and condensed into large bundles of tendons. These replace the stout, column-like central muscles, which are present in other linguliforms but apparently absent in acrotretides. The larval shell, which is retained near the pedicle opening, has a strongly pitted texture. The adult shell is smooth and has a rounded outline, and is phosphatic like other linguliforms. Subgroups * Superfamily Acrotretoidea Schuchert, 1893 ** Family Acrotretidae Schuchert, 1893 (Lower Cambrian - mid-Silurian We ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]