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 pilosus
is distinguished from R. acuen, R. bockmanni,
R. chromodontus, R. dani, R.
dinizae, R. hera, R. jumaorum,
R. loxochelis n. sp., R. marginalis
n. sp., and R. pentakelis 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, 27.1–34.9%
snout length (vs. orbit 18.9–24.6% snout length).
Rhinotocinclus pilosus is distinguished from
R. britskii, R. discolor, R.
eppleyi, R. isabelae n. sp., R.
kwarup, R. longirostris, R. polyochrus,
R. variola, and R. yaka by having
the belly naked or almost naked between lateral abdominal
plates, with none or one row of granular platelets
in the middle (vs. belly fully plated). It is further
distinguished from the species above except R.
isabelae n. sp., by having 1–2 lateral
abdominal plates (vs. 3–6 plates); and from
R. isabelae n. sp. by the shallower caudal
peduncle (6.3–7.5% vs. 8.1–8.8% SL), and
by having 31–37 premaxillary teeth (vs. 21–29
& 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
pilosus from the Latin pilosus, meaning hairy,
in allusion to the dense cover of hyperthrophied odontodes
typical of the species. An adjective. (Reis
& Lehmann 2022).
Igarapé Traíra, ca. 35 km E of rio Madeira
on Transamazon road, Humaitá, Amazonas, Brazil,
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.