Austrofundulus limnaeus (Schultz 1949)

Tomas Hrbek, Donald C. Taphorn & Jamie E. Thomerson, 2005, Molecular phylogeny of Austrofundulus Myers (Cyprinodontiformes: Rivulidae), with revision of the genus and the description of four new species., Zootaxa 825, pp. 1-39 : 22-25

Austrofundulus limnaeus (Schultz 1949)

Figure 11

Austrofundulus transilis Myers 1942: 110-112 (in part; specimens from Lake Maracaibo Basin described, some of which were later types of A. t. limnaeus Schultz 1949 ). Myers 1952: 135, 139 (figure and discussion of annual life cycle). Hoedeman 1958: 26-27 (head scales illustrated; no locality given). Weitzman and Wourms 1967: 89, 100 (generic characters; photo of A. t. limnaeus paratypes). Thomerson 1971: 21-28 (in part; several Venezuelan localities listed). Vaz-Ferreira and Sierra de Soriano 1972: 38-40 (head and lateral neuromast patterns for specimens from Lagunillas, Venezuela are given).

Austrofundulus transilis limnaeus Schultz 1949 : 85-88 (original description; holotype illustrated).

Austrofundulus stagnalis Schultz 1949 : 82-89 (original description). Taphorn and Thomerson 1978: 414: (synonymized with A. limnaeus ).

Holotype. UMMZ 141916: An adult male (61.0 mm) in good condition from the lower Río Cocuiza drainage 15 km west of San Felix, on the western border of Falcón state, Venezuela; collected by F. Bond on 21 March 1938.

Paratypes. UMMZ 141917, thirty two of the 34 paratypes were collected with the holotype, and of these nine were members of the species Rachovia pyropunctata (Taphorn and Thomerson 1978) . The two other paratypes were collected by P. Wagner Hummelick in Pozo de Arroyo de Arara, El Cardon, Guajira; according to the here-proposed classification, these specimens are transferred to the paratype series of the species Austrofundulus guajira .

Diagnosis. This species is distinguished from all species of Austrofundulus by the presence of iridescent blue-green spots present on its caudal peduncle and the basal portion of its caudal fin. This character is present in all sexually mature males. Intensity of the iridescent spots varies along a north-to-south gradient. Individuals from the northern coastal deserts occur in very turbid environments, and have corresponding more intense iridescent colors, while individuals from more southern, less turbid habitats have less intense colors.

Description. See also: (Schultz 1949; Taphorn and Thomerson 1978). In general, the color seems to reflect a gradation that seems correlated to the amount of yearly rainfall and the resultant variety in habitat. In the northern end of the distribution, the extremely arid coastal deserts near Quisiro, males have bright blue-green caudal fins and numerous iridescent blue spots on the body, particularly on the caudal peduncle. The over all background body color is dominated by a strong blue-green hue. Sides of the body near the head are light with few darker spots. Proceeding south, where populations inhabit progressively less xeric habitats, the background body color becomes darker, and the number of iridescent spots decreases. These populations were originally described as A. stagnalis by Schultz. In the southern-most portions of the species’ distribution, the background body color becomes rich golden brown with very few blue spots on the body. The southern-most populations inhabit clear, tea colored waters, while the northern-most populations inhabit heavily turbid waters, laden with light-colored inorganic silt (Podrabsky et al. 1998).

Specifically, the males have a light bluish, gray-bluish, grayish or gray-greenish colored background in the dorsal fin with several curved rows of darker spots, the proximal ones larger, less numerous, and arranged more regularly than the distal ones. Females have clear dorsal fins with a few gray, golden or light green spots. Males have intricately colored caudal fins, combining flecks and spots over variously colored background. Shiny iridescent green and/or blue are the dominant background colors. The basal two thirds of the caudal fin are scaled, ranging from iridescent blue-green to bronze with light yellow tint as one proceeds from north to south, while iridescent blue-green is the dominant color of the unscaled portion of the caudal fin. The iridescent blue spots present on the caudal peduncle extend into the caudal fin, and are especially prominent in the scaled portion of the caudal. The spots are often joined in an irregular line-like pattern. Similar to the body, the density of iridescent spots decreases as one proceeds south. The whole fin is mottled with black specks. The posterior edge of the caudal fin is often grayish. Both the dorsal and the ventral edge of the caudal fin extend to form a “lyre-tail”. Females have a drab brown to gray caudal fin, with few gray spots. The anal fin of males has a basic plan of light background with curved rows of darker spots. The base color is reddish-brown or golden with light blue to dark brown or gray spots. The basal spots are often diffused, more like amorphous blotches. The area surrounding these blotches is often white or light brown. The anal fin of females is golden near the base, clear or light gray distally, with a few faint basal spots. The pectoral fins of both sexes are clear or dusky-gray, with a few faint spots. Pectoral fin rays are easily visible. The pelvic fins of males have a similar color pattern to the anal fin, however, are much less intense. The basic background color tends to be reddish-brown, with few faint spots. The pelvic fins of females are clear to light gold, with faint spots. The sides of the body of males are complexly patterned. The background color is light gray to brown, with dark brown spots or flecks in the anterior portion of the body. In the middle and posterior portion of the body, the spots become lighter, changing into numerous white, light yellow or iridescent blue spots. The ventrum is lighter brown or cream, without spots, while the dorsum is darker than the rest of the body. In females, the sides are gray or brown, occasionally with darker outline of each scale. The body is not spotted, or only rarely a few gray spots are present behind the pectoral fin base. As in males, the abdomen of females is lighter than the rest of the body, while the dorsum is darker. In both sexes a dark brown or black bar passes obliquely through the eye onto the head posteriorly above and anteriorly below the eye. The iris is usually silver, sometimes golden. In males, the intensity of this pattern decreases as one moves south, while in females this pattern is generally less pronounced. An outstanding feature of the head is the yellow or gold opercle. Rear portion of the opercle is covered with large shiny scales that change color with the angle of reflected light. The upper portion of the hear is brown or tan, the lower cream or tan. In females the head is predominantly gray or olive dorsally, and lighter ventrally. For meristics see Table 6.

Distribution. We here restrict the distribution to the eastern shores of the Lake Maracaibo; from the far western coastal border of Falcón State south through much of eastern Zulia to Santa Apolonia, Trujillo State. Despite intensive collecting, neither A. limnaeus nor any other Austrofundulus species, have been found in the southern region of Lake Maracaibo.