Mobile Chub

description

Conservation Status. Although this species has occasionally been collected in large numbers, ongoing stream modifications and habitat alteration throughout the lower Mobile Bay basin do not bode well for its future. In particular, construction of the Tenn-Tom waterway, which has changed the original free-flowing Tombigbee River into a series of standing pools, has served to eliminate this species from a major portion of its original geographic range. This species should be closely monitored throughout remaining parts of its range.

Morphological and genetic evolution in eastern populations of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae), with the descriptions of four new species

description

Figs. 1 B, 2; Table 1 Hybopsis hyostomus. — Gilbert 1891: 155, 157 (in part; records from Tuscaloosa, Alabama). Hybopsis aestivalis. — Cook 1959: 129 – 130 (in part; general account; considered very rare in Mississippi). Extrarius aestivalis. — Mayden 1989: 14 (in part; chub clade; phylogeny based on cranial osteology). Extrarius sp. cf aestivalis. — Boschung 1989: 50 (Tombigbee River distribution map; diagnoses of two undescribed species in Mobile Bay basin; ecological notes).

Morphological and genetic evolution in eastern populations of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae), with the descriptions of four new species

description

M. boschungi differs from M. etnieri (Fig. 1 C) in pharyngeal-tooth count (4 - 4 vs. 1,4 - 4,1); position of anal opening about two-thirds (70 percent) of distance between pelvic and anal-fin origins (vs. midway); dorsal-fin positioned directly above pelvic fins (vs. distinctly posterior); a less heavily spotted body; and longer maxillary barbels. M. boschungi differs from M. pallida (Fig. 1 D) in having a single pair of maxillary barbels (vs. two pairs); eight anal rays (vs. seven); position of anal opening about two-thirds of distance between pelvic and anal-fin origins (vs. midway); a slightly more heavly spotted body. (vs. essentially pallid); and a greater average body size, as discussed in the individual species accounts. Description. Characters listed in the Diagnosis are not repeated here, unless additional clarification is required. Variation in meristic characters is presented in Table 1. Dorsal rays 8; anal rays 8 (rarely 7); pectoral rays usually 15 (occasionally 14 or 16); pelvic rays usually 8 (rarely 7); lateral-line scales usually 36 – 37 (range 35 to 39); body-circumferential scale rows above and between lateral lines on opposite sides of body usually 11, occasiona

Morphological and genetic evolution in eastern populations of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae), with the descriptions of four new species

description

Macrhybopsis sp. cf M. aestivalis “ A ” (Gulf Chub). — Boschung & Mayden 2004: 209, plate 21 A (general account [refers in part to Macrhybopsis tomellerii]; color illustration).

Morphological and genetic evolution in eastern populations of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae), with the descriptions of four new species