GILBERT: FISHES OF THE SUBGENUS LUXILUS


N. pilsbryi, which it resembles superficially so closely that it has been
confused with zonatus in the literature (Evermann and Hildebrand,
1916: 444).
 N. ariommus differs from typical forms of Luxilus in the form of
the scales on the side of the body, which are normal in shape instead
of high and diamond-shaped. From N. zonatus and N. pilsbryi it
also differs in lacking prominent scallops on the posterior edge of the
lateral scales and the black stripe along the side of the body.
 While no other Notropis species shares so many features with
Luxilus as ariommus does, Notropis pyrrhomelas of the headwater
areas of the southern Piedmont Plain, which Gibbs (1957) placed in
the subgenus Cyprinella, shares the following characteristics with N.
coccogenis and N. zonistius: Dark pigmentation on the dorsal fin; a
dark crescent-shaped blotch of pigment in the fork of the caudal; high
diamond-shaped scales on the side of the body; a large eye; a prom-
inent dark scapular bar; a peritoneum heavily flecked with black; and
10 anal rays. The last character is found in only a few populations
of zonistius. N. pyrrhomelas differs from coccogenis and zonistius in
having a 1,4-4,1 dental formula. The similarities suggest fairly close
ties between the subgenera Cyprinella and Luxilus.

 KEY TO SPECIES AND SUBSPECIES OF THE
 SUBGENUS LUXILUS

la. A dark band on dorsal fin (may be orange-red in young). Peri-
 toneum heavily speckled with dark melanophores, but not uni-
 formly black. A red stripe usually present in life on cheek or
 on margin of opercle and preopercle. Nuptial tubercles in two
 or three rows along lower jaw extending to tip of chin. Dorso-
 lateral scales heavily margined with dark. Circumferential scales
 usually 13 to 15-2-10 to 12 2---_ -------
 2a. Black band on posterior half of dorsal fin almost parallel to
 distal margin. A wide black border in fork area of caudal
 fin. No caudal spot. Prominent red bar at margin of opercle
 and preopercle. Body more slender and terete. No nuptial
 tubercles on top of head, back, or dorsal fin. Angle between
 mouth and top of head usually 50 to 520. Vertebrae 40 to
 42, usually 41 _____------__________Notropis coccogenis
 Tennessee, Savannah, Catawba and New drainages; Ala-
 bama, Tennessee, Georgia, South Carolina, North Carolina,
 and Virginia.


1964