Cyprinodontiformes
(rivulines, killifishes and
live bearers)
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| Family: Anablepidae Common name: Four-eyed fishes and jenynsiids Order: Cyprinodontiformes (rivulines, killifishes and live bearers) Class: Actinopterygii (ray-finned fishes) Remark: Chiefly freshwater and brackish; rarely coastal marine. Distribution: southern Mexico to southern South America. In Anablepinae eyes prominently raised above top of head; each eye divided lengthwise into upper and lower parts giving rise to two pupils each for the right and left eyes; individuals swim with center of eye aligned with the water level and are capable of double vision. Anal fin turned into tubelike gonopodium. Gonopodium and female genital aperture either dextral or sinistral. Males and females divided equally into sinistral and dextral mating types. Viviparous. Maximum length 32 cm in Anablepinae, 12 cm in Jenynsiinae. |
| Family: Aplocheilidae Common name: Rivulines Order: Cyprinodontiformes (rivulines, killifishes and live bearers) Class: Actinopterygii (ray-finned fishes) Remark: Distribution: Africa, southern Asia, southern North America, and South America. Small space between pelvic fin bases. Metapterygoid present. Basibranchials 3. First two dorsal radials each with a ray. One species, Rivulus marmoratus, is a true hermaphrodite (self-fertilizing). Internal fertilization; one species with gonopodium. Egg-laying. Some species are annuals. |
| Family: Cyprinodontidae Common name: Killifishes (toothcarps) Order: Cyprinodontiformes (rivulines, killifishes and live bearers) Class: Actinopterygii (ray-finned fishes) Remark: Chiefly freshwater and brackish; rarely coastal marine. Distribution: southeastern Canada to South America, Africa, Madagascar, southern Europe, and southern Asia. Egg-laying. Males without gonopodium. Pelvic bases relatively far apart. Pelvic fins may be absent. No metapterygoid. The first 2 dorsal radials with only 1 ray. About 16 cm maximum length. |
| Family: Goodeidae Common name: Goodeids Order: Cyprinodontiformes (rivulines, killifishes and live bearers) Class: Actinopterygii (ray-finned fishes) Remark: Distribution: west central Mexico. Fertilization internal. Viviparous. Males with the anterior rays of anal fin crowded, shorter, and partly separate from rest of fin (suspected as a primitive gonopodium called pseudophallus). Ovaries partly fused to form a single median organ. Embryos and newborn young usually with ribbonlike structures called trophotaeniae which functions like a placenta. Body form and feeding habits diverse. Attains 20 cm maximum length. |
| Family: Poeciliidae Common name: Livebearers Order: Cyprinodontiformes (rivulines, killifishes and live bearers) Class: Actinopterygii (ray-finned fishes) Remark: Distribution: low altitudes from eastern United States to northeastern Argentina. Anal fin with the first 3 rays unbranched. Anterior anal fin rays in males form a gonopodium. Fertilization internal. Viviparous. Some species with all-female individuals, their eggs capable of developing when stimulated by the sperm of another species without fertilization. Usually less than 18 cm maximum length. |
