Middle Ordovician – Late Devonian
Drepanellidae is an extinct family of epifaunal suspension feeders.
Description of the Family
- Subquadrate to subrectangular.
- Well defined cardinal angles.
- Lateral surface lobate or with nodose lobes.
- Frequently has spines.
- Surface smooth granular, pitted or finely reticulate.
Treatise on Invertebrate Paleontology, Part Q, Arthropoda 3 (1961):
- Carapace subquadrate to subrectangular; hinge long, dorsum straight, cardinal angles subequal and well defined; lateral surface lobate or with nodose lobes, nodes commonly terminating as spines with one or more overreaching dorsum; surface smooth granular, pitted, or finely reticulate; marginal ridge or carina subparallel to free margin, poorly developed posteriorly; valves subequal. Hingement by simple tongue and groove but unknown in some forms. Dimorphism unknown.