Leporacanthicus triactis, photo by M.H. Sabaj
Leporacnthicus sp. cf. galaxias, photo by M.H. Sabaj
The following is an excerpt from Armbruster (1997).
Leporacanthicus is diagnosed by three unique characteristics:
large foramina in the anterohyal, a small cartilage just posterior to the
mesethmoid disk, and a long foraminal section of the prootic. Other
characteristics considered synapomorphic for Leporacanthicus are:
reduction in the length and width of the accessory process of the first
ceratobranchial to 3/4 the length of the main body and thin, loss of the
posterior wall of the fourth epibranchial, elongated first hypobranchials,
posterior position of the interohyal, long pharyngeal teeth, loss of the
posterior pouch of the posterohyal, a dorsal foramen on the hyomandibula,
the levator arcus palatini crest terminating dorsal to the metapterygoid
facet for articulation with the lateral ethmoid, loss of the raised triangular
section at the junction of the levator arcus palatini crest and the preoperculo-hyomandibular
ridge, a mesial ridge at the anterodorsal corner of the metapterygoid facing
anteriorly, loss of contact of the metapterygoid facet and the lateral
wall of the pterygoid channel, a tall supraoccipital crest, presence of
a cartilage at the anterior corner of the mandible, a straight, bowling-pin
shaped maxilla, a large canal plate that deflects under the head, the lateral
line continuing onto the plate beyond the hypurals, reduction in the size
of the ossified Baudelotís ligament to a short shelf, the metapterygoid
condyle of the lateral ethmoid forming a lateral shelf, thick ribs, four
or more predorsal plates, loss of abdominal plating, and barbels over the
Called the vampire plecostomus in the aquarium literature in reference
to the large teeth in the upper jaw. Species of Leporacanthicus
are medium-sized loricariids with a narrow, pointed head, round lower lip,
and fleshy tentacles on the upper lip. Color pattern is generally
dark gray to black with white to golden spots or a light gray with medium-sized
black spots. Abdomen naked. Caudal fin straight, angled posteroventrally.
Three predorsal plates. Two teeth per premaxilla that are much longer
than the dentary teeth.
Leporacanthicus is readily identifiable from all other Ancistrini by the development of usually only two teeth in each premaxilla, the inner teeth being very long (all other Ancistrini have more than two teeth in the premaxilla), by having a well-raised supraoccipital crest (the supraoccipital in most of the Ancistrini is flat to slightly raised) and by having numerous long fimbriae above the upper jaws. Leporacanthicus looks most similar to some Panaque, Spectracanthicus, and Megalancistrus, and Pseudacanthicus from which it can also be identified by a round lower lip (vs. oval) and fimbriae on the upper lip. In addition, Spectracanthicus has the dorsal fin connected to the adipose fin spine (well separated in Leporacanthicus) and Panaque has a wide, rounded head (vs. pointed and narrow in Leporacanthicus) and much stouter teeth.
Mouth of Leporacanthicus sp. cf. galaxias showing the fimbriae of the upper lip, the round lips, and the very long premaxillar teeth (just one on each side in this specimen). Photo by M.H. Sabaj.
The genus has been reported from the upper Orinoco, the eastern, north-flowing
Amazon tributaries, and the Rio Tocantins (Stawikowski, 1992).
The type of L. triactis was pulled from a deep hole in a mud bank (L. Nico, pers. comm.). It has been hypothesized that the enlarged teeth of the upper jaw are used to remove snails from their shells (Burgess 1994). We have observed this in L. joselimai, but specimens from Venezuela seem to have a lot of caddis flies in the gut as well as freshwater sponges.
Armbruster, J.W. 1997. Phylogenetic relationships of the sucker-mouth armored catfishes (Loricariidae) with particular emphasis on the Ancistrinae, Hypostominae, and Neoplecostominae. Unpubl. Ph.D. dissertation. University of Illinois, Urbana-Champaign. 409 pp.
Burgess, W.E. 1994. Scobinancistrus aureatus, a new species of loricariid catfish from the Rio Xingu (Loricariidae: Ancistrinae). Tropical Fish Hobbyist 43:236?242.
Stawikowski, R. 1992. Die Gattung Leporacanthicus Isbrücker & Nijssen, 1989. Harnischwelse, DATZ-Sonderheft, September 1992: 58-61.