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 hardmani
is sympatric and syntopic with R. collinsae
in the Potaro River, having been collected together
at the same spot. Despite both species are superficially
similar, they have many distinguishing characters.
Rhinotocinclus hardmani is easily diagnosed
from R. collinsae by having few and minute
teeth accessory teeth, while they are numerous and
large in R. collinsae, by the large urogenital
papilla of males, which is 3–4 times bigger
than that of R. collinsae, by males lacking
a skin flap on first pelvic-fin ray, which is present
in R. collinsae, by having the belly naked
or almost naked between lateral abdominal plates,
while it is fully plated in R. collinsae,
and by having the adipose-fin spine coalesced to the
dorsum, while it is free from the dorsum on R.
collinsae. Rhinotocinclus hardmani was
tentatively categorised as Least Concern (LC) by Lehmann
et al., (2022) in the original description. (Reis
& 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 Parotocinclus hardmani.
Potaro River, Essequibo River basin in the Region
of Potaro-Siparuni, Guyana. Type locality:
Kuribrong River at Grass Shoals Rapids, Potaro-Siparuni,
Guyana, 05°28’44.7”N 59°31’54.4”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.