''Streptopinna'' is an Indo-Pacific
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
mollusc
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
s characterized by a roughly triangular outline. There is only one species, ''Streptopinna saccata''.
Description
No two "baggy pen shells" are alike; they grow into unexpected shapes, conforming to the shape and position of other hard structures (rocks, coral skeletons, empty shells) in their immediate environment.
Distribution
Warm waters of the tropical Indian and western Pacific oceans.
Habitat
Buried in sandy bottoms.
Pinnidae
Taxa named by Eduard von Martens
Monotypic bivalve genera
{{Bivalve-stub