Morphological and molecular analyses reveal a new species of stygobitic amphipod in the genus Crangonyx (Crustacea: Crangonyctidae) from Jackson County, Florida, with a redescription of Crangonyx floridanus and notes on its taxonomy and biogeography

Crangonyx manubrium, a new stygobitic species, is described from hypogean localities in Jackson County, Florida. This analysis is based on detailed morphometric and genetic comparisons of Jackson County Cave populations with epigean populations of Crangonyx floridanus, including paratypes from Highlands Hammock State Park, the type locality of C. floridanus. The original description of C. floridanus was partially based on a population from Gerard's Cave, in Jackson County, which is now assigned to C. manubrium n. sp. Crangonyx floridanus is morphologically redescribed based on paratype material from Highlands Hammock State Park, Highlands County, Florida and a population from Hogtown Creek in Gainesville, Alachua County, Florida. Molecular and morphological analyses show surprising variation across the range of C. floridanus, indicating it may represent a species complex.