Relationships in the Pseudacris nigrita Complex in Southwestern Georgia

Abstract

U NTIL 1940, only two races of the chorus frog, Pseudacris nigrita (Le Conte), were known from the coastal plain of the southeastern United States. One of these, P. n. verrucosa (Cope), is limited to peninsular Florida. The other, P. n. nigrita, is widely distributed in the southeastern coastal plain to the north of the peninsula. A third form, the Piedmont-inhabiting P. n. feriarum (Baird), was reported from Florida by Carr (1940), who treated this form as a distinct species. He reported finding feriarum in 1935 apparently common locally along the Apalachicola River in Liberty County in western Florida. Carr was aware that nigrita also occurred in Liberty County, but reported no nigrita-feriarum integradation in his samples from this area. Presumably because of this, he assumed that the relationship between the two was at the species rather than the subspecies level. While Carr did not specifically discuss the spatial relationships of nigrita and feriarum in relation to their sympatry in Liberty County, he did differentiate between their Florida habitats locating nigrita in pine flatwoods; high and mixed hammocks and feriarum in low hammock; river and creek floodplains and swamps. He felt that the major streams tributary to the Apalachicola River, the Flint and the Chattahoochie, had served as invasion pathways for feriarum and other Piedmont species and noted that their survival after invasion was probably dependent upon the Piedmont-like terrain found along the Apalachicola River in Florida. Neill (1949) described intergradation between nigrita and feriarum some 250 miles to the northeast of Liberty County, Florida, along the fall line of eastern Georgia, and returned feriarum to its former status as a subspecies of nigrita. Smith and Smith (1952) interpreted Neill's comments to mean that intergradation between nigrita and feriarum was known to occur in western Florida, and thus, that there was no geographic overlap of the two forms in this area.