Lower Cambrian (upper Atdabanian) – Holocene
Lingulata is an extant class of stationary, epifaunal suspension feeders.
Characteristics of the Class
- Inarticulate brachiopod
- Ventral and dorsal mantle lobes completely separated in adults
- Pedicles of extant species contain coelomic cavities
- Well developed posterior body wall
Treatise on Invertebrate Paleontology, Part H, Vol. 2 (2000):
- Pedicles of living species with coelomic cavities, developing as outgrowth of posterior part of ventral mantle lobe; dorsal and ventral mantle lobes completely separated in adults; posterior body wall usually well developed; musculature usually composed of single or paired umbonal muscle, three or four pairs of oblique muscles (reduced in Acrotretida) and paired central muscles; lophophore with large and small brachial canal and two rows of filaments during trocholophe stage; mechanism of shell opening hydraulic, by means of well-developed dermal muscles in anterior body wall; digestive tract open, recurved, U-shaped, with anus placed anteriorly, near right nephridiopore; nervous system epidermal with only one subenteric ganglion and peripheral mantle nerves; sensory organs represented by statocysts; gonads on free edges of peritoneal bands; mantle canals usually with vascula terminalia directed peripherally and medially (except in Paterinida).