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 variola
is distinguished from R. acuen, R. bockmanni,
R. chromodontus, R. dani, R.
dinizae, R. hera, R. jumaorum,
R. pentakelis, R. marginalis n.
sp., and R. loxochelis n. sp. 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. hardmanni 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 triangular dark spot on the anterior portion of
the dorsal-fin membrane (vs. dorsal-fin spot absent);
a Y-shaped light mark from snout tip to nostrils (vs.
Y-shaped light mark absent); and a larger orbit, 27.1–31.0%
snout length (vs. orbit 18.9–24.6% snout length).
Rhinotocinclus variola is distinguished from
R. britskii, R. discolor n. sp.,
R. eppleyi, R. isabelae n. sp.,
R. kwarup, R. longirostris, R.
pilosus n. sp., and R. yaka by having
dark dots smaller than a pupil diameter broadly distributed
dorsally and ventrally on body (vs. dark dots absent,
but sometimes darkened sensory pores may be present
on head); a triangular dark spot on anterior portion
of the pectoral-fin membrane (vs. dark spot absent);
and, except for R. isabelae n. sp., the triangular
dark spot of the dorsal fin occupying more than half
of the fin (vs. dark spot occupying less than half
of dorsal fin). (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. Named from
the Latin variola, meaning smallpox, spotted, in allusion
to the dark dots that cover all dorsal and ventral
body surfaces. A noun in apposition. Remarks:
Most online searches at the moment (2022) will still
give you the old genus name of Parotocinclus variola.
Quebrada Tacana, a tributary to the Amazon River in
Colombia. Type Locality: Colombia,
Departamento Amazonas, Leticia, Quebrada Tacana, tributary
to rio Amazonas at km 6.5 of road from Leticia to
Tarapacá, 04°09’15”S 69°56’09”W.
Froese, R. and D. Pauly.
Editors. 2022. FishBase. World Wide Web electronic
publication. www.fishbase.org, ( 08/2022 )
Lehmann, A.P., L.J. Schvambach and
R.E. Reis, 2015. A new species of the armored
catfish Parotocinclus (Loricariidae: Hypoptopomatinae),
from the Amazon basin in Colombia. Neotrop. Ichthyol.
13(1):47-52. 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.