Species: Gambusia yucatana, Yucatan Gambusia

Gambusia yucatana Regan, 1914

Yucatan Gambusia

Head and body moderately robust, moderately compressed at rear; head depressed; front nostril not tubular; covering of eye not continuous with skin of head; mouth small, opens at front, slightly oblique, lower jaw slightly projecting, top jaw protractile; jaw teeth consist of an outer row of large backward curved teeth, and several rows of small pointed teeth; 1 dorsal fin with short base, at rear of body, 8-9 (7-10) rays; anal fin origin distinctly before dorsal fin origin in both sexes, female with 10-11 rays; pelvic origin well behind pectoral base, near anal fin, tips of fins of males not swollen; pectorals high on flank, 14 (13-15), modified in male, with 5th ray scalloped near its tip; 3rd anal ray unbranched; anal fin modified in male to form an elongate sex organ, that greatly elongate organ not slender, pointed with tip curved upwards and with 2 small recurved hooks on its top side, without a fleshy palp; tail base relatively narrow; tail fin rounded; scales smooth and relatively large; 28-31 (usually 29-30) in lateral series.

Light olive, upper body with large dark brown to black spots, scattered or in several rows; a narrow dark bar under eye, if present, restricted to preoperculum (not extending onto operculum); lower margin of tail fin of males bright orange; tail fin with 2-3 vertical rows of dark spots; dorsal fin with 1 dominant row of dark spots, fainter rows may also be present.

Reaches 6.7 cm.

Freshwater mainly, but also in estuaries, mangroves and along beaches in eelgrass.

Depth range: 0-2 m.

SW Gulf of Mexico to Belize.