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 acuen
was also described as a member of Hisonotus,
and accordingly compared to other species of the later
genus (Silva et al., 2014). Interestingly, in the
diagnosis of the new species the authors begin saying
“Hisonotus acuen differs from all congeners
except H. bockmanni, H. chromodontus,
H. insperatus, H. luteofrenatus,
H. oliveirai, and H. paresi by having
a functional V-shaped spinelet”. Both H.
bockmanni and H. chromodontus are herein
being tranferred to Rhinotocinclus and the
remaining species have already been transferred to
Curculionichthys, the functional V-shaped
spinelet indeed diagnosing R. acuen and,
in fact, all Rhinotocinclus and Curculionichthys
species, from Hisonotus. Extintion risk of
Rhinotocinclus acuen is currently not assessed.
& Lehmann 2022).
Etymology: Rhinotocinclus masc.,
from the Greek (Rhinos), beak, snout and Otocinclus,
a genus of Hypoptopomatinae, in allusion to the conspicuous
and elegant snout of most of its species. Remarks:
Most online searches at the moment (2022) will still
give you the old genus name of Hisonotus acuen.
Upper Xingu River basin, Mato Grosso, Brazil. Type
locality: Brazil, Mato Grosso State, municipality
of Querência, affluent of Rio Toguro, Rio Xingu
basin, 13°00’26”S 52°11’27”W.
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.