This genera is similar to
the Ancistrus in appearance. They possess
three stout odonodes concealed beneath the gill covers
which act as a defense mechanism. Hopliancistrus
tricornis is distinguished from its congeners
by having four branched rays on anal fin (vs. five
branched rays). Description: Distinguished
from its congeners except H. munduruku by
having large yellowish-white spots along the body,
and dark brown spots on fins (vs. body covered by
conspicuous small greenish-yellow dots of similar
size on head, trunk and fins in H.
spots on posterior portion of the body moderate in
size, usually smaller than pupil in H. xikrin;
all fins covered by large yellowish-white spots in
H. xavante). Can be distinguished from its
congeners except H. wolverine by a narrow,
bar-shaped connection strut between anterior process
of compound pterotic and main body, leaving a large
posterior gap (vs. connection strut as a continuous
sheet). Differs from H. wolverine and H.
xikrin by pectoral-fin spine length 25.1–29.9%
of SL (vs. 32.1–38.4% of SL and 32.1–35.7%
of SL, respectively). It also differs from H.
xikrin by the transverse process of first dorsal-fin
pterygiophore sutured to the transverse process of
the second pterygiophore (vs. absence of contact between
the transverse processes of first and second dorsal-fin
pterygiophores). Differs from H. xavante
by caudal peduncle depth 9.7–11.3% of SL (vs.
11.5–12.9% of SL); by narrow nasal bone plate
(vs. broad nasal, sometimes slightly triangular, see
Fig 2); and by having nuchal plate exposed, and covered
by odontodes (vs. nuchal plate covered by thick skin
and usually lacking odontodes. Habitat:
Hopliancistrus tricornis is apparently restricted
to the middle portion of the Rio Tapajo's basin in
the São Luiz rapids, and its main tributaries,
such as the lower portions of Rio Jamanxim and Rio
Itapacura. This species is also found in small tributaries,
such as Igarape Leitoso, tributary of the Rio Cupari,
Ruro´polis municipality, Para´ State.
Aquarium Care: Likes a current in
the aquarium and are peaceful habitants. Likes a higher
temperature and need frequent water changes to keep
them in good health. Sexual Differences:
Males posses a broad head region and more prominent
bristling on the edge of the snout. Diet:
Omnivore; veg foods such as lettuce, spinach, cucumber
and veg. tablets. Live and frozen foods such as Cyclops,
Daphnia and brine shrimp.
South America:Tapajós and Xingu River basins in
Brazil. Type locality: Brasilien,
Est. Pará, Poça de Pedra no Rio Tapajós,
RR, Zuanon J, Py-Daniel LHR, Birindelli JLO, Sousa LM
(2021) Taxonomic revision of Hopliancistrus Isbru¨cker
& Nijssen, 1989 (Siluriformes, Loricariidae) with
redescription of Hopliancistrus tricornis and description
of four new species. PLoS ONE 16(1): e0244894.
Ferraris, C.J. Jr.,
2007. Checklist of catfishes, recent and fossil (Osteichthyes:
Siluriformes), and catalogue of siluriform primary types.
Zootaxa 1418:1-628. Froese, R. and D. Pauly. Editors. 2020.
FishBase. World Wide Web electronic publication. www.fishbase.org,
( 12/2020 ). Montoya-Burgos, J.-I.,
S. Muller, C. Weber and J. Pawlowski, 1998.
Phylogenetic relationships of the Loricariidae (Siluriformes)
based on mitochondrial rRNA gene sequences. p. 363-374.
In L.R. Malabarba, R.E. Reis, R.P. Vari, Z.M.S. Lucena
and C.A.S. Lucena (eds.) Phylogeny and classification
of neotropical fishes. Porto Alegre: EDIPUCRS. Seidel, I.
2008. Back to Nature guide to L-catfishes, Ettlingen,
Germany 208 p.