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Reis & Lehmann 2022 (3)

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) (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. 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. Remarks: Most online searches at the moment (2022) will still give you the old genus name of Parotocinclus halbothi.

None

Parotocinclus halbothi

Loricariidae

Soth America: 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 Suriname.

3.0cm. (1¼ins)

25-27°c (77-81°f.)

5.5-6.5.

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.