Killifish

description

Description. The males have an iridescent blue-green dorsal fin with black edges, showing approximately five curved rows of dark spots. Females have clear dorsal fins with light gray spots. Males have iridescent blue-green caudal fins, with scattered black pigment. The color is more intense proximally; distally the fin is dark gray. Both the dorsal and the ventral edge of the caudal fin extend to form a “ lyre-tail ”. Females have clear to light brown caudal fin. The anal fin of males is similar to the dorsal and caudal fins. A background of iridescent blue-green near the base is broken with about three bars of dark brown, with start at the base and curve out anteriorly, away from the body. The distal third of the anal fin is sometimes brown or sooty gray, but the proximal blue-green background may extend all the way to the distal edge. Females have clear light brown anal fins, with four to five brown spots. Both the pectoral and pelvic fins of males are reddish-brown, with easily visible rays. The pectoral and pelvic fins of females are clear or light gold. The sides of the body of males are complexly patterned. The reddish-brown background gets progressively darker from ventral t

Molecular phylogeny of Austrofundulus Myers (Cyprinodontiformes: Rivulidae), with revision of the genus and the description of four new species.

diagnosis

Diagnosis. Austrofundulus rupununi is distinguished from all other species of Austrofundulus by the presence of black to dark brown humeral spots above the pectoral fin, iridescent blue-green dorsal fin with black edges, showing approximately five curved rows of dark spots, and iridescent blue-green caudal fins, with scattered black pigment. Compared with other species of the “ limnaeus ” group, A. rupununi have larger scales reflected in the counts as significantly fewer lateral, transverse, caudal peduncle and breast scales; they also have fewer dorsal, and pectoral fin rays than other Austrofundulus species; as well as the greatest caudal peduncle depth of any Austrofundulus species.

Molecular phylogeny of Austrofundulus Myers (Cyprinodontiformes: Rivulidae), with revision of the genus and the description of four new species.

discussion

Remarks. In general, individuals of Austrofundulus rupununi are phenotypically “ intermediate ” between the most gracile or delicate species of the genus, A. transilis, of the Venezuelan Llanos and the rest of the species previously known as A. limnaeus which attain a larger size and are robust predators. Similarly to A. transilis they have relatively small body size, and do not appear to be very aggressive. As in the A. limnaeus species group this species also has highly developed male coloration, as well as dorsal and ventral extensions on the caudal fin. In general, the over all tone of the body coloration is pastel, rather than the more gaudy color patterns seen in other Austrofundulus species.

Molecular phylogeny of Austrofundulus Myers (Cyprinodontiformes: Rivulidae), with revision of the genus and the description of four new species.

distribution

Distribution. Known only from the Rupununi savannah in Guyana, of the upper Tacutu River drainage which flows into the Branco and is part of the Amazon River Basin. This species is expected to occur to the south in the savannahs surrounding Boa Vista, Roraima, Brazil, but to date no Austrofundulus has been confirmed in this region. It is the only Austrofundulus known from an Amazon Drainage system.

Molecular phylogeny of Austrofundulus Myers (Cyprinodontiformes: Rivulidae), with revision of the genus and the description of four new species.