Etheostoma marmorpinnum Blanton & Jenkins, 2008
Marbled Darter

Family:  Percidae (Perches), subfamily: Etheostomatinae
Max. size:  4.06 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  North America: USA. Etheostoma marmorpinnum occurs in lower Little River (Tennessee drainage), Blount County, Tennessee, but is generally rare in the upstream reaches. The species does not appear to be continuously distributed. The stronghold is just upstream of the backwaters of Fort Loudoun Reservoir (Layman 1991). Also known from a single specimen from the South Fork Holston River in Sullivan County, Tennessee, collected in 1947, three years before construction of the South Fork Holston Dam was completed. The capture site was 0.6 rkm above the dam, whose tailwater has long been and continues to be cold-water. The species is now extirpated from the Holston River (Ref. 79849).
Diagnosis:  Etheostoma marmorpinnum is distinguished from all other members of the species complex by higher percentage of belly covered by scales (60–80% vs. 10% or less); higher percentage of body area along the first dorsal-fin base covered with scales (100% vs. 70% or less); dark distinct marbling in second dorsal fin of nuptial males (vs. lighter diffuse marbling or marbling absent); narrower band width for caudal fin (range = 12–15% of fin length vs. 15–25%) and anal-fin (range = 29–33% vs. 33–58%); more scales around caudal peduncle (25 vs. 23 or 24); and higher first dorsal fin (D1H, =117 vs. 105 or less). The species is further distinguished from E. percnurum by fewer caudal fin rays (15 vs. 18); narrower distal band on pectoral fin (range = 17–20% vs. 27–32% of fin length) and second dorsal fin (14–21% vs. 23–25% of fin height); and by prominent tessellation of medial region of caudal fin of nuptial males (vs. uniformly dusky). Further distinguished from E percnurum and E. sitikuense by an intermediate number of pored lateral-line scales (27 vs. 22 or 33 respectively). Means of other measurements were also informative in distinguishing E. marmorpinnum from other members of the complex (Ref. 79849).
Biology: 
IUCN Red List Status: Critically Endangered (CR); Date assessed: 21 December 2011 (B1ab(iii)+2ab(iii)) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


Source and more info: www.fishbase.org. For personal, classroom, and other internal use only. Not for publication.