Rhyacoglanis varii has the posterior tip
of the post-cleithral process reaching vertical through
the base of the dorsal-fin spine (vs. not reaching
in R. epiblepsis and R. rappydanielae).
Rhyacoglanis varii differs from R.
the longer distance of anus to anal-fin origin (mean
= 11.4±0.8% vs. 10.0±1.4% SL), maxillary
barbel length (mean = 79.6±5.8% vs. 74.8±8.7%
SL), and caudal peduncle depth (mean = 9.5±0.5%
vs. 8.8±0.5% SL); minor posterior nostril to
eye distance (mean = 4.8±0.9% vs. 6.7±1.3%
SL), body depth (mean = 18.2±1.5% vs. 21.4±2.6%
SL), and postcleithral process length (mean = 12.9±1.1%
vs. 13.9±1.2% SL). Rhyacoglanis varii
differs from R.
R. seminiger by the shape of the pectoral-fin
spine, with anterior serrae distributed along the
entire margin (vs. restricted to the proximal half)
(Shibatta et al). Habitat:
Rhyacoglanis varii is known only from the
upper rio Tocantins basin on the Brazilian shield.
Colouration: Rhyacoglanis varii
is easily distinguished from congeners (except for
R. pulcher) by the colour pattern, with the
dark brown vertical bar below the dorsal-fin base
not confluent with a dark brown bar below the adipose-fin
base (vs. broadly confluent in R. seminiger),
the subdorsal dark brown bar becomes abruptly thinner
ventrally (vs. broader in R. paranensis),
dark brown spots sparsely distributed on the body
(vs. dense in R. epiblepsis and R. rapppydanielae),
and a solid dark brown bar on caudal peduncle (vs.
becoming light brown inside, resembling a circle,
in R. annulatus) (Shibatta et al).
Aquarium Care: Predatory in the
aquarium towards fish that are smaller. Provide plenty
of hiding places to hide during the day and best kept
in a small group of 2-3. Very secretive in its surroundings.
Diet: No problem with eating all types of
aquarium fare, flake, tablets, pellets, live and frozen
foods. Etymology: The species name
varii honours the ichthyologist Richard P. Vari (1949–2016)
for his outstanding contributions to the systematics
of Neotropical fishes.
South America:Upper rio Tocantins basin on the Brazilian
shield. Type Locality: Rio do Peixe,
upper Rio Tocantins basin, Goianésia, state
of Goiás, Brazil.
Shibatta OA, Souza-Shibatta
L. New species of Rhyacoglanis (Siluriformes:
Pseudopimelodidae) from the upper rio Tocantins basin.
Neotropical Ichthyology. 2023; 21(1):e220075.