Ptychobranchus subtentum

Ptychobranchus subtentum, also known as the fluted kidneyshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.

Ptychobranchus subtentum
Conservation status
Near Threatened  (IUCN 2.3)[1]
Imperiled  (NatureServe)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Unionida
Family:	Unionidae
Genus:	Ptychobranchus
Species:	P. subtentum
Binomial name
Ptychobranchus subtentum (Say, 1825)

This species is endemic to the drainages of the Cumberland River and the Tennessee River in the United States.^[2]

Reproduction

All Unionidae are known to use the gills, fins, or skin of a host fish for nutrients during the larval glochidia stage. Ptychobranchus subtentum enclose their larvae in a membranous capsule that resembles the pupae of black flies. When a fish bites the capsule bait, the Ptychobranchus subtentum larvae are forced out through the mimic capsule's "eyes" and then attach to the gills of the host fish.^[3]

Host species of this bradytictic mussel include Etheostoma obeyense, Etheostoma rufilineatum, Etheostoma flabellare, Etheostoma caeruleum and Cottus carolinae.^[2]

Shell morphology