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 halbothi
is distinguished from all congeners, except R.
collinsae and R. hardmanni, by having
accessory teeth on both premaxilla and dentary; the
odontodes on the ventral surface of first pelvic-fin
ray aligned with main ray axis (vs. odontodes bent
and pointing mesially); and lacking a light mark from
the snout tip to nostrils (vs. light mark present
and Y-, V-shaped or as two separate lines). Rhinotocinclus
halbothi 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 a triangular
dark spot on the anterior portion of the dorsal-fin
membrane (vs. dorsal-fin spot present); and from R.
acuen, R. bockmanni, R. chromodontus,
R. dani, R. dinizae, R. hera,
R. jumaorum, R. pentakelis, R.
loxochelis n. sp., and R. marginalis
n. sp. by possessing an adipose fin (vs. adipose fin
absent). Rhinotocinclus halbothi is distinguished
from R. collinsae and R. hardmanni
by having 4–7 series of middle abdominal plates
(vs. 0–1 series). It is further distinguished
from R. collinsae by having the adipose-fin
spine coalesced to the dorsum (vs. adipose fin normally
developed), and by a shorter pectoral fin (46.3–55.8%
vs. 58.2–69.1% HL); and from R. hardmani
by having many and large accessory teeth (vs. few
and minute teeth), a normally developed urogenital
papilla in males (vs. urogenital papilla 3–4
times bigger than normal), skin flap on first pelvic-fin
ray of males (vs. skin flap absent), and belly fully
plated between the lateral abdominal plates (vs. belly
naked or almost naked between lateral abdominal plates)
& 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. Halbothi,
Named for Brazilian ichthyologist Dário Armin
Halboth, an excellent field biologist and one of the
first researchers to study the effects of bauxite
tailings deposited in an Amazonian lake (lago Batata
a floodplain lake located in the floodplains of rio
Trombetas, Pará State) on fish communities.
Before his early death, Dário Halboth dedicated
himself to describe the ecological features of the
fishes living in streams of Amapá State, Brazil.
Most online searches at the moment (2022) will still
give you the old genus name of Parotocinclus halbothi.
Occurs in the Rio Trombetas basin, a tributary to
the Amazon in the states of Amazonas and Pará,
Brazil, and in the upper Marowijne River, in southern
Froese, R. and D. Pauly.
Editors. 2022. FishBase. World Wide Web electronic
publication. www.fishbase.org, ( 02/2022 )
Lehmann, A.P., H. Lazzarotto and R.E. Reis,
2014. Parotocinclus halbothi , a new species of small
armored catfish (Loricariidae: Hypoptopomatinae),
from the Trombetas and Marowijne River basins, in
Brazil and Suriname. Neotrop. Ichthyol. 12(1):27-33
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.