Austrofundulus transilis Myers 1932

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 : 13-15

Austrofundulus transilis Myers 1932

Figure 6

Austrofundulus transilis Myers 1932 : 159-162 (original description of genus Austrofundulus , and A. transilis ). de Beauford 1940: 110 (specimens of A. guajira from Guajira peninsula listed). Myers 1942: 110-112 (based on specimens of A. limnaeus and possibly other species from Lake Maracaibo Basin). Schultz 1949: 82, 85-89 (description of subspecies A. t. transilis , and A. t. limnaeus ; key, data on holotype of A. t. transilis ). Myers 1952: 135, 138-139 (life cycle, figure of A. limnaeus {labeled as A. transilis } from near Lake Maracaibo). Hoedeman 1958: 25, 27 (frontal head scale pattern for “ Austrofundulus transilis ” but author does not identify material used to prepare figure). Weitzman and Wourms 1967: 89-100 (discussion of annual killifish genera, refers to A. transilis {= A. limnaeus or one of the new species described here} figure 3 shows a fish of the A. limnaeus group identified as A. transilis ). Turner 1967: 845 (distribution of Rachovia hummelincki and “ A. transilis ” compared, but Austrofundulus sites refer to species of the A. limnaeus group). Scheel 1969: 11-16 (frontal scale pattern and caudal scales discussed for “ A. transilis ” but material not identified). Thomerson 1971: 23 (discussion of distribution of A. transilis limnaeus in relation to that of R. hummelincki ). Goldstein 1972:51 (color photo identified as A. transilis is probably A. leohoignei ). Thomerson and Turner 1973: 786 ( A. transilis listed as syntopic with other annual form Caño Benito area of the Venezuelan Llanos). Vaz-Ferreira and Sierra de Soriano 1972: 36-40 (lateral line and head pore patterns for A. transilis = A. limnaeus species group). Taphorn and Thomerson 1975: 67-73 (photo, key, color description, distribution).

Holotype. USNM 92191. An adult male (40.0 mm) from a pond in the state of Guarico, Río Orinoco basin, Venezuela; collected by F. F. Russell in 1928 (precise date is unknown).

Paratypes. None.

Diagnosis. Austrofundulus transilis is the smallest of all species of Austrofundulus . It is distinguished from all other species of Austrofundulus by pastel light tan to pink-grey background body color, and the lack of any black markings on the body. Males of A. transilis have pink to red background color on all fins with occasional blue-green highlights between the fin rays; this fin color pattern is also diagnostic.

Description. A small proportion of males also have an iridescent blue-green or black ocellus on the dorsal fin. The caudal fin is rounded and without “lyre-tail” extensions (usually present in A. rupununi , morphologically the most similar species). Pelvic and pectoral fins are lighter than the unpaired fins. Females have clear fins. The sides of the body of males are unpatterned. The dorsum of the body is light tan anterior to the dorsal fin, and gets progressively pinker posterior to the dorsal fin, and on the sides of the body. Each scale is lightly outlined with white or lighter pink. The abdomen is pale, almost white. In females, the basic color is plain light tan. As in males, the abdomens of females are lighter than the rest of the body. The iris of the eye is silver. A faint eye bar is usually visible; however, this character varies with the temperament of the fish. For additional characters see Myers (1932), Taphorn and Thomerson (1978) and Table 3.

Distribution. Known from the Llanos of the Río Apure drainage, and from the lower Río Unare basin (Fig 1).

Remarks. Austrofundulus transilis are small, relatively non-aggressive fish when compared to A. limnaeus and the other species described in this paper. Although there is sexual differentiation in the color pattern, it is subtle compared to the other Austrofundulus species.