Percina crypta, the Halloween Darter, is described as a new species endemic to the Chattahoochee and Flint River systems in Georgia and Alabama. Percina crypta differs from sympatric Percina nigrofasciata in having narrowly separated dorsal saddles (inter-saddle spaces typically less than or equal to saddle width, compared to frequently wider than saddle width in P. nigrofasciata), in usually possessing a single modified scale between the pelvic bases (compared to two or more in P. nigrofasciata), and in having dark wide bands on pectoral-fin rays (versus pectoral fin clear, or with irregular dark marks or weak tessellations on fin rays in P. nigrofasciata). Phylogenetic relationships of P. crypta to other species of Percina are obscure. Percina crypta occurs in shoal and riffle habitats in the Chattahoochee and Flint River mainstems and in a few tributary systems, with the known extant range comprising four disjunct areas separated by mainstem impoundments and altered river reaches.
Simulations of hydrologic response in the Apalachicola-Chattahoochee-Flint River Basin, Southeastern United States