Chiapas catfish

Lacantunia enigmatica is a species from the order of catfish -like ( Siluriformes ), which is endemic in the river system of the Rio Lacantún a tributary of the Rio Usumacinta in Chiapas ( Mexico). It is the only species in the monotypic genus thus Lacantunia. The genus name is derived from its home waters off the Art epithet enigmatica means as much as " puzzling " and is a nod to the unexpected discovery of Art

Features

Lacantunia enigmatica has a moderately elongated body, the front is weak, more flattened rear side. The top is medium to dark brown and has larger specimen, small dark irregular spots. The underside of the fish is much brighter, white, cream or medium gray. Males of Lacantunia enigmatica achieve a maximum length of 42 cm, females remain only a little smaller. At the head Lacantunia has four pairs of barbels.

The pelvic fins are slightly behind the middle of the body below the last dorsal fin rays, the caudal fin is rounded or currently completing with rounded corners. The adipose fin is long and thick, it begins after about 70 % of standard length, clearly separated from the dorsal fin.

Fins formula: Dorsal II/8-10, Anal 22-26, Ventral 6, pectoral I/10-11

The spine has 55 to 57 vertebrae, 22 to 25 Präcaudalwirbel (before the anus lying) and 31 to 33 caudal vertebrae ( vertebrae of the tail ). The Weberian apparatus was formed by six vertebrae and the ribs of the sixth vertebra.

Way of life

Lacantunia enigmatica lives in deep sections of the river with stone bed and rapids of mountain streams. The previously catches were caught throughout the year, always at night. Lacantunia enigmatica feeds on fish, crabs, shrimp and large plant seeds.

System

Lacantunia differs by five autapomorphe characteristics of all other catfish and is therefore placed in a separate family. This includes characteristics of the skull bones, the skeleton of the gill and the air-bladder.

The closest relatives of Lacantunia are six families of African catfish, which is referred to as the "Big Africa " group. Sister group are the Claroteidae. The separation from his African relatives, obtained by the method of molecular clock is said to have occurred millions of years ago about 94-75 after the separation of Africa and South America. Since the relatives are all fresh water fish, the spread of the ancestors of Lacantunia during the global warming period in the late Cretaceous or early Tertiary is drawn over a land bridge in today's Bering Strait into consideration.