Ptychobranchus occidentalis is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of freshwater mussel, an aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 bivalve mollusk in the family Unionidae

Unionidae

Unionidae is a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, naiads, or simply as unionids.The range of distribution for this family is world-wide...

, the river mussels.

This species is endemic to the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Reproduction

All Unionidae are known to use the gills, fins, or skin of a host fish for nutrients during the larval glochidia stage. Ptychobranchus occidentalis enclose their larvae in a membranous capsule that resembles host prey such as larval insects or larval fish . When a fish bites the capsule bait, the Ptychobranchus occidentalis larvae are released out of the rupture and attach to the gills of the host fish.

Source

• Bogan, A.E. 1996. Ptychobranchus occidentalis. 2006 IUCN Red List of Threatened Species. Downloaded on 7 August 2007.
• http://molluskconservation.org/MC_GALLERY/Gallery1.html