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 pentakelis
is distinguished from all congeners, except for R.
bockmanni, R. dani, R. hera,
R. marginalis n. sp., and R. loxochelis
n. sp. by having the dominant colour pattern formed
by dark bars on body well separated and distinct (vs.
dominant colour pattern formed by wide dark bars partially
coalesced or closed together, or formed by a dark
stripe from the snout tip, through the eye and extending
to end of caudal peduncle); having two separate light
lines from snout tip diverging to each nostril (vs.
light lines on snout absent, Y- or V-shaped); and
by having teeth with yellow cusps (cusps light ochre
or brown). Rhinotocinclus pentakelis is further
distinguished from R. britskii, R. discolor,
R. eppleyi, R. isabelae, R.
kwarup, R. longirostris, R. pilosus,
R. polyochrus, R. variola, and R.
yaka by lacking an adipose fin (vs. adipose fin
present). Rhinotocinclus pentakelis is further
distinguished from congeners, except R. bockmanni,
R. dani, R. loxochelis n. sp., and
R. marginalis n. sp., by having small platelets
at adipose-fin position (vs. small platelets absent).
Rhinotocinclus pentakelis is distinguished
from R. bockmanni by lacking a triangular
dark spot at the dorsal-fin membrane (vs. dorsal-fin
dark spot present), and by having a conspicuous dark
bar 2 on body (vs. bar 2 absent or inconspicuous).
It is distinguished from R. hera by having
small platelets at adipose-fin position (vs. small
platelets absent) and yellow teeth cusps (vs. light
ochre cusps); and from R. dani by the deeper
body (body depth 18.4–20.8% vs. 16.3–18.3%
SL; caudal peduncle depth 10.1–11.7% vs. 8.8–9.9%
SL; head depth 43.6–49.5% vs. 38.0–43.5%
HL), and longer dorsal-fin spine (27.0–30.8%
vs. 24.0–27.0% SL). Rhinotocinclus pentakelis
is further distinguished from R. loxochelis
n. sp. by the regularly arranged dark bars on body
(vs. dark bars on body somewhat fragmented and inclined,
such that they connect to form a zig-zag pattern),
and the comparatively shorter head (head length 37.5–39.7%
vs. 39.3–41.3% HL); and from R. marginalis
n. sp. by the comparatively deeper caudal peduncle
(10.1–11.7% vs. 9.1–10.1% SL and 26.3–29.7%;
vs. 23.3–26.3% HL) (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 pentakelis.
Tocantins River basin, Tocantins, Brazil. Type
locality: Brazil, Tocantins State, municipality
Lavandeira, Rio Palmas, Rio Tocantins basin; 12°48’05”S
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.