> Physa species A

> Habitat & Distribution
This undescribed species is characteristic of shallow, temporary, or vernal ponds and ditches in regions close to the southern coast.  In habitat, life history, and shell form it is reminiscent of the northern physid genus Aplexa.

> Ecology & Life History
Our laboratory cultures reach maturity around 7 – 9 weeks post hatch, about a week later than typical P. acuta and much behind P. pomilia.  Although Physa Species A reaches a greater maximum size than either of the other two South Carolina Physa species, its fecundity in laboratory culture is lower.

> Taxonomy & Systematics
This species has probably been confused both with P. acuta and with P. pomilia (or hendersoni) in the past, although sequence data confirms the distinction (Wethington 2004, Wethington & Lydeard 2007).  Populations can typically be recognized by their dark bodies and slender shells.  They freely hybridize wiith P. acuta, but F1 hybrids are sterile.  "Species A" does not successfully hybridize with P. pomilia.  Currently awaiting formal description by Wethington, Wise, & Dillon.

For notes regarding generic placement of this and other physid species of the American southeast, see my essay below.

> Essay 
The phylogenetic analysis of Wethington & Lydeard (2007) prompted me to review the systematics of the Physidae on 12Oct07.

> Maps of Physa distribution
Click the small map to enlarge it, or download the state-specific PDFs



North Carolina (PDF)

South Carolina (PDF)

Georgia (PDF)

> References
Wethington, A. R. (2004a)  Phylogeny, taxonomy, and evolution of reproductive isolation in Physa (Pulmonata: Physidae)  Ph.D. dissertation, University of Alabama, Tuscaloosa.  Wethington, A. R. (2004b)  Family Physidae.  A supplement to the workbook accompanying the FMCS Freshwater Identification Workshop, University of Alabama, Tuscaloosa.  24 pp. (PDF)    Wethington, A. R. & C. Lydeard (2007)  A molecular phylogeny of Physidae (Gastropoda: Basommatophora) based on mitochondrial DNA sequences.  J. Molluscan Stud. 73: 241 - 257.   Wethington, A. R.,  J. Wise, & R. T. Dillon (in prep)  Genetic and morphological characterization of the Physidae of South Carolina (Pulmonata: Basommatophora), with description of a new species.