Hopliancistrus tricornis, Holotype, MZUSP 22007, Photo by J.W. Armbruster
The presence of three stout, strongly curved odontodes in the cheek mass putatuvely separate Hopliancistrus from all other Ancistrini; however, the actual number of hypertrophied cheek odontodes is 1-16 with 1-5 of those being stout and recurved. The genus was not examined in Armbruster (1997) or (2004), but I have recently obtained data on it and it is in a polytomy with Neblinichthys, Dekeyseria and a clade of Ancistrus, Lasiancistrus and Pseudolithoxus. The body color is dark and mottled in the preserved specimens with a slight hint of white spots, but in life, the white spots are much more well-developed. Males develop really stout odontodes at the corners of the snout (see below). The only other ancistrin that develops hypertrophied odontodes just in the corners of the snout is Lasiancistrus, but Lasiancistrus have the odontodes very thin and very long like whiskers and Lasiancistrus has three rows of plates on the caudael peduncle vs. five in Hopliancistrus.
Hopliancistrus tricornis, Holotype, Head showing the large, recurved cheek odontodes and the stout odontodes at the corners of the snout, Photo by J.W. Armbruster
Type locality given as Brazil, Para, river Tapajos, and Mato Grosso,
upper Xingu river (Isbrücker and Nijssen, 1989).
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.
Isbrücker, I.J.H. and H. Nijssen. 1989. Diagnose dreier neuer Harnischwelsgattungen
mit fünf neuen Arten aus Brasilien (Pisces, Siluriformes, Loricariidae).