User:Wikij151/Athearnia anthonyi

Anthony's Riversnail
Conservation status
Vulnerable
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Sorbeoconcha
Family:	Pleuroceridae
Genus:	Athearnia
Species:	A. anthonyi

Athearnia anthonyi

Athearnia anthonyi, commonly known as Anthony's Riversnail, is a rare species of freshwater snail in the family Pleuroceridae. It is native to the Tennessee River system in the United States, but the three main populations occur in the main branch, the Sequatchie River, and Limestone Creek.

Taxonomy

The genus Athearnia included two species, A. anthonyi and A. crassa, although the latter is now extinct, and now A. anthonyi is the only species in this genus within Pleuroceridae. Athearnia used to be considered a subgenus of the Leptoxis genus in the Pleuroceridae family.

A main population of A. anthonyi snails that live in the Sequatchie River were compared to another species of snail, Leptoxis praerosa. One group of L. praerosa lived with the A. anthonyi snails is Sequatchie River, and the other group lived farther away, in Duck River. The groups of snails were compared by shell morphology, sizes, and genetic information gathered by using allozyme electrophoresis, a technique that can separate proteins and allows for genetic analysis. Individuals from each population were gathered and examined, and shells were opened to observe if there were parasites in the digestive system of the snails. Tissue samples were then taken for allozyme electrophoresis. Results showed that the shells of A. anthonyi had whorls that started higher on the shell with a deep keel or ridge. As this species ages, the shells smooth out and has more similarities to L. praerosa shells. No parasites were found in A. anthonyi snails, suggesting that their large size was not due to parasitic gigantism and was normal for the species. There was large variation of allele frequencies at five different loci when comparing these two species, and heterozygosity suggested no inbreeding or bottlenecks within all populations. This, along with the size and shell differences, marks A. anthonyi as its own species. Although, similar allele frequencies at six other loci can support the Athearnia genus as being a subgenus of Leptoxis.

Habitat

Within this river system, Anthony's Riversnail occupies larger rivers with smooth rocks at the bottom, such as cobblestones. They also occupy creeks in areas with low elevation and streaming water.

Conservation Efforts

The conservation status of this species is listed as vulnerable by the IUCN. However, other sources go further and consider this species endangered everywhere but the places where experimental populations are located.

Along with the natural main populations of this snail, two experimental populations were established in Alabama and Tennessee along the Tennessee River to focus on recovery efforts. The Limestone Creek population proved to have the best chance of survival between the three main populations, so a few thousand individual snails were moved from Limestone Creek to the experimental population in Alabama. However, establishing a new population with these individuals failed thought to be due to erosion in the area at the time.