Rhamdella cainguae Bockmann & Miquelarena, 2008
Argentina, Provincia Misiones, Departamento Cainguás, Aristóbulo del Valle, Arroyo Cuña-Pirú in the Balneario Municipal (27º10´S 54º50´W), holotype ILPLA 1087 (130 mm SL, male)
Bockmann, F.A. & M.A. Miquelarena (2008):
Anatomy and phylogenetic relationships of a new catfish species from northeastern Argentina with comments on the phylogenetic relationships of the genus Rhamdella Eigenmann and Eigenmann, 1888 (Siluriformes, Heptapteridae).
Zootaxa 1780: 1-54
abstract (from publication):
Rhamdella cainguae, a new species of the family Heptapteridae is described from the Arroyo Cuña-Pirú, a tributary of the Río Paraná, in the subtropical forest of Misiones, northeastern Argentina. The presence of a large differentiated ovoid area on the supraorbital laterosensory canal along the frontal-sphenotic boundary, delimited by the slender dorsal walls of the bones, and with no foramen for a laterosensory branch, is an autapomorphy for R. cainguae. A detailed description of the skeleton and laterosensory system of R. cainguae is provided. The genus Rhamdella is rediagnosed on the basis of three autapomorphies: a very large opening in the frontal for the exit of the s6 (epiphyseal) branch of the supraorbital laterosensory canal (reversed in R. rusbyi), a large optic foramen, and a dark stripe along the lateral surface of the body (reversed in R. rusbyi). Rhamdella is considered to be the sister group of a large heptapterid clade composed of the Nemuroglanis sub-clade plus the genera Brachyglanis, Gladioglanis, Leptorhamdia, and Myoglanis. Rhamdella is herein restricted to five valid species: R. aymarae, R. cainguae, R. eriarcha, R. longiuscula, and R. rusbyi. A sister group relationship between R. aymarae and R. rusbyi is supported by three synapomorphies. Rhamdella cainguae shares 12 apomorphic features with R. eriarcha and R. longiuscula.
distribution & habitat (from publication):
Known only from the type locality, Arroyo Cuña-Pirú, Río Paraná basin, in northeastern Argentina. Habitat. Specimens were collected with seine or hook-and-line, over rocky bottoms in a clear water stream (ca. 50–100 cm deep, with pools around 3 m deep), running through a densely forested subtropical area. Individuals demostrated a tendency for gregarity as they were densely grouped under large stones.