Excerpted from Rocío Rodiles-Hernández, Dean A. Hendrickson, John G. Lundberg and Julian M. Humphries. 2005. Lacantunia enigmatica (Teleostei: Siluriformes) a new and phylogenetically puzzling freshwater fish from Mesoamerica. Zootaxa 1000:1-24. PDF of paper
A new family (Lacantuniidae), genus and species of catfish, Lacantunia enigmatica, is described
from the Río Usumacinta basin of Chiapas, México. This odd siluriform is diagnosed by five distinctively
autapomorphic and anatomically complex structures. The fifth (last) infraorbital bone is
relatively large, anteriorly convex and remote from a prominent sphenotic process. The lateral margin
of the frontal, lateral ethmoid and sphenotic bones are thick at the origins of much enlarged
adductor mandibulae and levator arcus palatini muscles; otherwise the skull roof is constricted and
flat. One pair of cone-shaped "pseudo-pharyngobranchial" bones is present at the anterior tips of
enlarged cartilages medial to the first epibranchial. A hypertrophied, axe-shaped uncinate process
emerges dorsally from the third epibranchial. The gas bladder has paired spherical, unencapsulated
diverticulae protruding from its anterodorsal wall. Lacantunia enigmatica cannot be placed within
or as a basal sister lineage to any known catfish family or multifamily clade except Siluroidei. This
species may represent an ancient group, perhaps of early Tertiary age or older, and it adds another
biogeographic puzzle to the historically complex Mesoamerican biota.
Color rendering with gas bladder in yellow
About the Species
This female specimen was collected by Rocío Rodiles-Hernández on 20 May 1997 in Ejido Zamora Pico de Oro in the state of Chiapas, México. It was made available for scanning by Dr. Dean Hendrickson, Dr. Julian Humphries, Dr. Tim Rowe and Dr. Ed Theriot of The University of Texas at Austin. Funding for image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of the Department of Geological Sciences, The University of Texas at Austin.
About this Specimen
The specimen was scanned by Matthew Colbert on 4 October 2002 along the coronal axis for a total of 1000 slices, each slice 0.117 mm thick with an interslice spacing of 0.092 mm.
Front page image.
Cranial Skeleton showing gas bladder, facial muscles, and palatine cartilage.
Illustration by Kyle Luckenbill