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de Pinna, Reis & Britski 2020 (3)

Description: Trichogenes beagle stands out as a remarkable species among trichomycterids due to unique morphological character states, which bring to light broader issues in the evolution of certain morphological complexes. One of them is the presence of the bone normally called antorbital, supraorbital, or frontolacrimal tendon bone in trichomycterids. The structure, here called the barbular bone, has been known for a long time in the family, and was first illustrated by Eigenmann (1918: 282, 377) in Hatcheria, Scleronema, and Eremophilus, misidentified as the nasal. The bone is present in the form of an elongated rod or splint, lacking any laterosensory canal association, extending from the margin of the frontal towards the lacrimal in all Trichomycterinae, and at least in basal members of the Sarcoglanidinae and Glanapteryginae. It is absent in Copionodontinae, Tridentinae (except in Potamoglanis), Stegophilinae, and Vandelliinae. Within Trichogenes, the bone is present in T. beagle and T. longipinnis, and absent in T. claviger. The condition of the structure in species of Trichogenes differs from that in all other trichomycterid taxa, having the shape of a flat, discoidal, or roughly triangular bone, dorsally concave, located at about midlength of the lateral process (sometimes called antorbital process) of the lateral ethmoid. Diet: Uses visual, tactile, and chemo-sensory orientation to feed on bottom-dwelling aquatic and terrestrial arthropods in the water column or on the surface. Diet includes immature aquatic insects, crustaceans, adult terrestrial winged insects whole or fragmented, as well as carrion. Forages mostly by scanning the bottom, the barbels touching the substrate, but visual oriented drift feeding is also employed by individuals up to 5 cm TL. While foraging may bury into sand or plant debris and sifts through opercular openings and mouth. Etymology: The genus name Trichogenes: meaning A combination of tricho– from Trichomycteridae and –genes from the cetopsid catfishes of Helogenes, referring to superficial resemblance to that genus (specifically, the long anal fin). The specific name beagle: The species epithet honours the Laboratory of Molecular Systematics – Beagle, Department of Animal Biology, Universidade Federal de Viçosa, the lab where the only specimens of the new species were found preserved.

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Trichomycteridae

South America: Rio Doce drainage, Minas Gerais (southeastern Brazil).

4.0cm. (1¾ins)

25-28°c (77-83°f.)

6.0-7.0.

de Pinna, Reis & Britski, 2020 A new species of Trichogenes (Siluriformes, Trichomycteridae), with a discussion on the homologies of the anterior orbital bones in trichomycterids and other loricarioids.
de Pinna, Reis & Britski, 2020 Rediscovery of Trichogenres beagle, (Siluriformes: Trichomycteridae) with comments on habitat and conservation status.
Santos, S. A. D., Reis, V. J. C., Marques, I. D. C. C., Pessali, T. C., Britski, H. A., & Pinna, M. D. (2025). Rediscovery of Trichogenes beagle de Pinna, Reis & Britski, 2020 (Siluriformes: Trichomycteridae) with comments on habitat and conservation status. Zootaxa, 5601(1), 196–200.