Lacantunia enigmatica
| Lacantunia enigmatica | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Lacantuniidae | ||||||||||||
| Rodiles-Hernández , Hendrickson & Lundberg , 2005 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Lacantunia | ||||||||||||
| Rodiles-Hernández, Hendrickson & Lundberg, 2005 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Lacantunia enigmatica | ||||||||||||
| Rodiles-Hernández, Hendrickson & Lundberg, 2005 |
Lacantunia enigmatica is a species of fish from the order of the catfish (Siluriformes), which occurs endemically in the river system of the Rio Lacantún, a tributary of the Rio Usumacinta in Chiapas (Mexico). It is the only species in the thus monotypical genus Lacantunia . The genus name is derived from its native waters, the species epithet enigmatica means something like "enigmatic" and is an allusion to the unexpected discovery of the species.
features
Lacantunia enigmatica has a moderately elongated body that is slightly flattened at the front and more flattened laterally at the rear. The top is medium to dark brown and, in larger specimens, has small, dark, irregular spots. The underside of the fish is much lighter, white, cream-colored or medium gray. Males of Lacantunia enigmatica reach a maximum length of 42 cm, females stay only slightly smaller. At the head has Lacantunia 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 closes straight off with rounded corners. The adipose fin is long and thick, it begins about 70% of the 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 precaudal vertebrae (lying in front of the anus) and 31 to 33 caudal vertebrae (tail vertebrae). The Weber's apparatus was formed of six vertebrae and the ribs of the sixth vertebra.
Way of life
Lacantunia enigmatica lives in deep river sections with stone beds and rapids from mountain streams. The specimens caught so far were caught all year round, always at night. Lacantunia enigmatica feeds on fish, crabs, shrimp, and large plant seeds.
Systematics
Lacantunia differs from all other catfish by five autapomorphic characteristics and is therefore placed in its own family. These include features of the skull bones, the gill skeleton, and the swim bladder .
Lacantunia's closest relatives are six families of African catfish, known as the "Big Africa" group. Sister group are the Claroteidae . The separation from its African relatives, determined using the molecular clock method, is said to have occurred about 94 to 75 million years ago after the separation of Africa and South America. Since the relatives are all freshwater fish, an expansion of the ancestors of Lacantunia during the global warm period in the late Cretaceous or early Tertiary over a land bridge at today's Bering Strait is being considered.
literature
- Rodiles-Hernández, Rocío; Hendrickson, Dean A .; Lundberg, John G .; Humphries, Julian M. (2005): Lacantunia enigmatica (Teleostei: Siluriformes) a new and phylogenetically puzzling freshwater fish from Mesoamerica . Zootaxa 1000: 1-24. ISSN 1175-5334 . PDF
Individual evidence
- ↑ JP Sullivan, Lundberg JG; Hardman M: A phylogenetic analysis of the major groups of catfishes (Teleostei: Siluriformes) using rag1 and rag2 nuclear gene sequences . In: Mol Phylogenet Evol. . 41, No. 3, 2006, pp. 636-62. doi : 10.1016 / j.ympev.2006.05.044 .
- ↑ Lundberg, John G .; Sullivan, John P .; Rodiles-Hernández, Rocío; Hendrickson, Dean A. (June 2007): Discovery of African roots for the Mesoamerican Chiapas catfish, Lacantunia enigmatica, requires an ancient intercontinental passage. Proceedings of the Academy of Natural Sciences of Philadelphia 156: 39-53. doi : 10.1635 / 0097-3157 (2007) 156 [39: DOARFT] 2.0.CO; 2 PDF ( memento of the original from March 26, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
Web links
- Lacantunia enigmatica on Fishbase.org (English)
- Lundberg, John G. 2005: Lacantuniidae Rodiles-Hernández, Hendrickson, and Lundberg 2005. Lacantunia enigmatica Rodiles-Hernández, Hendrickson, and Lundberg 2005. Chiapas Catfish. in The Tree of Life Web Project