Abstract:
A new species of the recently discovered miniature
tridentine catfish, Rhinotridens, is described
from the Amazon basin in Brazil, Colombia, and Peru.
It differs from Rhinotridens
chromocaudatus, type-species
of the genus, in having the caudal fin mostly hyaline,
a rictal barbel vestigial or externally absent, a
longer anal fin with 22–29 segmented rays, and
numerous other features from the skeleton. An osteological
account of the new species is provided based on cleared
and stained specimens, and traits of its external
morphology are revealed through scanning electron
microscopy (SEM), which for the first time reveal
details of the lip structure of tridentines. The seven
morphological characters previously listed as synapomorphies
for Rhinotridens are confirmed in the species
described herein, corroborating its generic allocation.
An additional characteristic from the morphology of
the lateral process of the autopalatine is proposed
as a novel synapomorphy for the genus (de
Pinna M, et al 2024). Etymology:The genus name Rhinotridens: From
rhino, latinised form of the Greek word rhinos (pivós),
meaning nose or snout, and Tridens, the type genus
of the subfamily. In allusion to the rostral protuberance
of the new genus. An adjective.The
specific name of britskii: Named in honour
of Heraldo Britski, first collector of specimens of
the new species, in recognition of his pivotal role
in the development of ichthyology in Brazil and also
as a token of his 90th birthday in 2024. A noun in
a genitive case. Remarks:
Rhinotridens britskii is spread over a large
geographic range, including localities in Brazil (rio
Purus, rio Madeira, and Ati-Paraná), in Colombia
(Río Loreto-Yacco) and in Peru (Río
Yanayacu). No significant threats to the species have
been identified in its area of occurrence. Thus, we
believe R. britskii can be provisionally
classified as Least Concern (LC) according to the
categories and criteria of the International Union
for Conservation of Nature (IUCN Standards and Petitions
Committee, 2022), (de
Pinna M, et al 2024).
Common
Name:
None
Synonyms:
None
Family:
Trichomycteridae
Distribution:
South America:Brazil (Rio Purus, Rio Madeira, and Ati-Paraná),
in Colombia (Río Loreto-Yacco) and in Peru
(Río Yanayacu).
Size:
1.5cm. (1¼ins)
Temp:
22-26°c (71-79°f.)
p.H.
6.0-7.0.
Reference:
de Pinna M, Reis V,
Pastana MNL, Datovo A. A new species of the
tridentine Rhinotridens from the Amazon basin (Siluriformes:
Trichomycteridae). Neotrop Ichthyol. 2024; 22(2):e240025. Neotropical
Ichthyology 2025
Rhinotridens
britskii Type locality-igarapé Boa Vista (Rio Javari
drainage), Atalaia do Norte Municipality
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