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 yaka 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, 26.9–32.5% snout length (vs.
orbit 18.9–24.6% snout length). Rhinotocinclus
yaka is distinguished from R. britskii
and R. kwarup, by having the snout more acutely
pointed (vs. snout more broadly rounded,); dark bars
on body wider and closer together (vs. dark bars on
body narrower and more widely spaced,); and 2–3
plates between the posterior border of the rostral
plate and the nostril (vs. one plate). Rhinotocinclus
yaka is distinguished from R. eppleyi
and R. longirostris by having 1–2 irregular
series of middle abdominal plates (vs. 4–5 irregular
series); and dark bars on body 1+2 fused (vs. five
dark bars on body). It is distinguished from R.
polyochrus, R. discolor n. sp., and
R. isabelae n. sp. by having more numerous
premaxillary teeth (34–39; vs. 23–32,
23–26 and 21–29 respectively). It is further
distinguished from R. polyochrus and and
R. isabelae n. sp. by its shallower body
(body depth 14.0–17.2% SL; vs. 17.9–20.0%
and 17.8–20.9% SL, respectively); and from
R. discolor n. sp. by having the triangular dorsal-fin
dark spot occupying nearly one third of the fin (vs.
small dorsal-fin spot). Rhinotocinclus yaka
is distinguished from P. variola by having
the triangular dorsal-fin dark spot occupying nearly
one third of the fin (vs. dorsal-fin spot occupying
more than half of the dorsal fin,), and by lacking
dark dots smaller than a pupil diameter broadly distributed
dorsally and ventrally on body (vs. dots present).
Rhinotocinclus yaka is finally distinguished
from R. pilosus n. sp. by having 1–2
irregular series of large middle abdominal plates
between the lateral abdominal plates (vs. belly naked
or with one series of granular plates in the middle,),
and by having 3–4 lateral abdominal plates (vs.
1–2 such plates), (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. The specific
name yaka: yaka, common name for non-loricariine
loricariids in both languages of the Tukano and the
Tuyuka ethnic groups of the upper Rio Tiquié,
Amazonas, Brazil, type locality. Remarks:
Most online searches at the moment (2022) will still
give you the old genus name of Parotocinclus yaka.
Common
Name:
None
Synonyms:
Parotocinclus yaka
Family:
Loricariidae
Distribution:
South America:
Rio Tiquié drainage, Amazonas, Brazil. Type
Locality: Brazil, Amazonas, Rio Tiquié
drainage, Igarapé Açaí near São
Pedro Village, approx. 00°16’N 69°58’W.
Rhinotocinclus
yaka Female, igarapé
Açaí near São Pedro Village, Rio Tiquié
basin, Amazonas, Brazil
Rhinotocinclus
yaka Dorsal view-Female,
igarapé Açaí near São Pedro Village,
Rio Tiquié basin, Amazonas, Brazil
Rhinotocinclus
yaka Ventral view-Female,
igarapé Açaí near São Pedro Village,
Rio Tiquié basin, Amazonas, Brazil
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