A new genus has been erected,
Rhinotocinclus, (2022) with the type species
of Parotocinclus longirostris Garavello,
1988. Abstract: A new genus of Hypopopomatinae
armored catfish is described from the northern portions
of South America, namely the Amazon, Orinoco and Guianan
coastal drainages. The new genus is diagnosed from
all remaining hypoptopomatines by having the canal
cheek plate on the ventral surface of the head posteriorly
elongated and contacting the cleithrum, in addition
to other features that distinguish the new genus from
specific genera. Five new species are described and
18 species currently allocated in Parotocinclus,
Hisonotus, and Curculionichthys
are transferred to the new genus and rediagnosed.
Parotocinclus amazonensis and P. aripuanensis
are considered junior synonyms of P. britskii.
The secondary sexual dimorphism of the members of
the new genus is detailed and illustrated. Morphological
characters are used to delimit four phenotypic groups
of species that might have phylogenetic significance,
which still have to be properly tested. A key to the
species is offered and diagnoses, illustrations, and
distribution maps are provided for all species (Reis
& Lehmann 2022).
Description: Rhinotocinclus discolor
is distinguished from R. acuen, R. bockmanni,
R. chromodontus, R. dani, R.
dinizae, R. hera, R. jumaorum,
R. loxochelis n. sp., R. pentakelis,
and R. marginalis n. sp. and by possessing
an adipose fin (vs. adipose fin absent), and by having
a Y-shaped light mark from the snout tip to each nostril
(vs. light mark V-shaped or present as two separate
lines from snout tip diverging to each nostril). It
is distinguished from R. collinsae, R.
halbolthi, and R. hardmani by lacking
accessory teeth on both premaxilla and dentary (vs.
accessory teeth present ); the odontodes on the ventral
surface of first pelvic-fin ray bent and pointing
mesially (vs. odontodes aligned with main ray axis
); a Y-shaped light mark from snout tip to nostrils
(vs. Y-shaped light mark absent); and a larger orbit,
29.8–36.2% snout length (vs. orbit 18.9–24.6%
snout length). Rhinotocinclus discolor is
distinguished from R. britskii, R. eppleyi,
R. kwarup, R. isabelae n. sp., R.
longirostris, R. pilosus n. sp., R.
polyochrus, R. variola, and R. yaka
by having a small, inconspicuous triangular spot at
the dorsal-fin base (vs. spot large and conspicuous).
It is further distinguished by having the dark transverse
bar 2+3 fused together (vs. bars not fused in R.
britskii, R. eppleyi, R. kwarup,
and R. longirostris, or bars 1+2 fused in
R. isabelae n. sp., R. pilosus n.
sp., R. polyochrus, R. variola,
and R. yaka) (Reis
& Lehmann 2022).
Etymology: Rhinotocinclus masc.,
from the Greek ????s (Rhinos), beak, snout and Otocinclus,
a genus of Hypoptopomatinae, in allusion to the conspicuous
and elegant snout of most of its species. Rhinotocinclus
discolor, from the Latin color, color, and the
prefix dis-, meaning not of the same color, in allusion
to the remarkable color pattern with the second and
third dark bars coalesced. A noun in apposition (Reis
& Lehmann 2022).
From Caño Pasa, tributary of Río Sipapo,
98 km from Puerto Ayacucho airport, Amazonas, Venezuela.
Reis RE, Lehmann A.
P. A new genus of armored catfish (Siluriformes:
Loricariidae) from the Greater Amazon, with a review
of the species and description of five new species.
Neotrop Ichthyol. 2022.