Percina crypta Freeman, Freeman & Burkhead, 2008
Halloween Darter
Percina crypta
photo by Burkhead, N.

Family:  Percidae (Perches), subfamily: Etheostomatinae
Max. size:  7.3 cm SL (male/unsexed)
Environment:  pelagic; freshwater
Distribution:  North America: USA. Percina crypta is endemic to the Apalachicola River drainage, where the species occurs in the Flint River system, Georgia, and the Chattahoochee River system, Alabama and Georgia (Ref. 79864).
Diagnosis:  Percina crypta differs from all other described species of Percina in possessing the following combination of characters: branchiostegal membranes slightly connected; preopercular margin non-serrate; premaxillary frenum well-developed; rectangular dorsal saddles usually seven, closely spaced; snout subconical, subocular bar prominent; and first-dorsal fin with yellow-orange to orange submarginal band in nuptial males and females. Nuptial males lack discrete tubercles, but exhibit tubercular ridges on the anal-fin rays and ventrally on pelvic rays. Lateral blotches rectangular, forming discrete blocks or bars, sometimes conjoined with dorsal saddles and tapering ventrally. Caudal-fin base with three vertically aligned spots or dashes that enclose two pale areas, middle mark may conjoin with small blotch at caudal base. Percina crypta is most readily distinguished from sympatric P. nigrofasciata in having narrowly separated dark dorsal saddles, pale inter-saddle width usually less than or rarely equal to saddle width versus pale intersaddle width usually greater than saddle width; width of last two dorsal saddles always greater than pale intersaddle space versus width of last two dorsal saddles always less than inter-saddle space; usually a single modified scale between the pelvic bases versus two or more scales; and pectoral-fin rays strongly banded versus fins clear or pectoral rays lightly tessellated. Lateral pigmentation highly variable in P. nigrofasciata; lateral blotches may conjoin with dorsal saddles in large adults and frequently taper ventrally onto lower side; subocular bar variably present; and nuptial males may develop a pale submarginal yellow wash suffused with pale iridescent green in the first-dorsal fin (Ref. 79864).
Biology:  Percina crypta inhabits relatively swiftly flowing areas over bedrock or a mixture of coarse (boulder to gravel) bed sediments (Hill 1996; Marcinek 2003). The species is frequently associated with the aquatic macrophyte Podostemum ceratophyllum (Marcinek 2003). All of our observations of P. crypta have been in shoal habitats, which contrasts markedly with the broader range of stream habitats (pools, runs and riffles) occupied by the co-occurring congener P. nigrofasciata (Ref. 79864).
IUCN Red List Status: Vulnerable (VU); Date assessed: 19 April 2012 (B2ab(iii)) Ref. (130435)
Threat to humans:  harmless


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