| Zusammenfassung: | Notropis albizonatus, n. sp., an endemic to the Tennessee and Cumberland river drainages, Kentucky, Tennessee, and Alabama, differs from other members of the Notropis procne species group in having a broad, depigmented supralateral stripe bordered ventrally by a dark midlateral stripe of equal intensity; predorsal stripe obsolescent or wanting; no postdorsal stripe; snout tubercles absent; lateral-line scales 36-38; predorsal scale rows 16-17; and unique genotypes for the Pgm-A locus. Only two disjunct populations of N. albizonatus persist, placing it among the most endangered fishes in North America. The species occurs in the Little South Fork (Cumberland River drainage, Kentucky) and Paint Rock River (Tennessee River drainage, Alabama) where it is an inhabitant of clear, clean pools and runs over rock bottoms. These two systems are being altered by toxic runoff, channelization, and siltation. The species was recently listed as federally endangered. Using the principle of parsimony, we optimized allelic frequencies for 37 presumptive loci on 945 possible unrooted trees for seven species: Notropis alborus, N. albizonatus, N. chihuahua, N. greenei, N. ludibundus, N. procne, and N. uranoscopus. We tested hypothesized sister relationships of N. albizonatus and estimated relationships in the N. procne species group. Notropis albizonatus and N. procne, formerly hypothesized as sister species, exhibit complete genotypic differentiation at three loci, Pep-S, Pgm-A, and Pgdh-A, and are not supported as sister species. Rooting the shortest network (L = 76.38) to either N. alborus or N. greenei, N. albizonatus, N. chihuahua, N. ludibundus, N. procne, and N. uranoscopus comprise a monophyletic assemblage. Notropis albizonatus is the sister species to a N. chihuahua-N. uranoscopus clade, and N. ludibundus-N. procne are sister species, comprising the sister group to the N. albizonatus clade.
|
|---|