Review of the andean armored catfishes of the genus Dolichancistrus Isbrücker (Siluriformes: Loricariidae)

Abstract

The loricariid catfish genus Dolichancistrus is reviewed and four species recognized. Species of Dolichancistrus are distinguished from each other by the degree of development of the pectoral-fin spine, the form of the distal margin of the pelvic fin, the relative size and form of the cheek plates, the pattern of odontodes along the margin of the snout, the presence versus absence of a buccal papilla at the premaxillary symphysis, and the relative lengths of the anal-versus pelvic-spines. Dolichancistrus atratoensis is known from the río Atrato system and the río Cubarradó on the Pacific versant of Colombia; D. carnegiei occurs in the eastern río Magdalena basin in the departments of Boyacá and Santander, Colombia; D. cobrensis inhabits southern tributaries of the Lago Maracaibo basin in Colombia and Venezuela along with some highland rivers of the Cordillera de Mérida in Venezuela draining into the río Orinoco system; and D. fuesslii is known from the Andean piedmont portions of the río Meta basin in the western río Orinoco system. Pseudancistrus pediculatus is considered a junior synonym of Ancistrus fuesslii. Chaetostomus setosus previously assigned to Dolichancistrus, was found to lack features characteristic of its putative congeners and is rather more closely related to other members of Chaetostoma group. Consequently, the species is herein considered as incertae sedis within that group. Dolichancistrus is diagnosed, a key is provided to the members of the genus, and diagnoses and redescriptions are provided for all of the recognized species.Se presenta una revisión del género Dolichancistrus y se reconocen cuatro especies válidas. Las especies de Dolichancistrus se distinguen entre sí a partir del grado de desarrollo de la espina pectoral, la forma del margen distal de la aleta pélvica, el tamaño relativo y la forma de las placas operculares, el patrón de odontoides a lo largo del margen del hocico, la presencia versus ausencia de papila bucal en la sínfisis de las premaxilas, y las longitudes relativas de las espinas anal y pélvicas. Dolichancistrus atratoensis es conocido del sistema del río Atrato y del río Cubarradó sobre la vertiente Pacífico de Colombia; D. carnegiei se encuentra en la vertiente Oriental de la cuenca del río Magdalena en los departamentos de Boyacá y Santander, Colombia; D. cobrensis habita los tributarios sureños de la cuenca del Lago Maracaibo en Colombia y Venezuela así como en algunos ríos de alta montaña de la Cordillera de Mérida en Venezuela drenando hacia el sistema del río Orinoco; y D. fuesslii es conocido de porciones pedimontanas Andinas de la cuenca del río Meta en la región occidental del sistema del río Orinoco. Pseudancistrus pediculatus es considerado un sinónimo junior de Ancistrus fuesslii. Chaetostomus setosus, una especie previamente considerada dentro del género Dolichancistrus, carece de los caracteres diagnósticos de sus congéneres putativos y es considerada como más cercanamente relacionada con otros miembros del grupo Chaetostoma. Consecuentemente, esta esp...

A new species of Chaetostoma, an armored catfish (Siluriformes: Loricariidae), from the río Marañón drainage, Amazon basin, Peru

“…The tufts of odontodes on the trunk lateral dermal plates of Chaetostoma spondylus at first resemble the "keeled plates" pattern in Acanthicus Spix & Agassiz, Leporacanthicus Isbrücker & Nijssen, Megalancistrus Isbrücker, and Pseudacanthicus Bleeker (Armbruster, 2004;Ballen & Vari, 2012), in which some odontodes in the middle of the plate are more developed and project past the posterior border of each plate. The plates of Chaetostoma spondylus are, however, mostly flat with the ventral series of plates gently curved in the middle and not forming keels.…”

Description of <i>Loraxichthys lexa</i>, new genus and species (Siluriformes: Loricariidae) from the Río Huallaga Basin, central Peru, with notes on the morphology of the enigmatic <i>Lipopterichthys carrioni</i> Norman, 1935

“…Novel morphological traits described in this work and in the recent taxonomic revision of Dolichancistrus (Ballen & Vari 2012) are potential characters to be evaluated in future phylogenetic studies. Furthermore, the taxonomic revision and phylogenetic analyses of the genera Chaetostoma and Cordylancistrus are ongoing projects, which will probably lead to nomenclatural changes.…”

“…Since the derived characters that would diagnose Chaetostoma, Cordylancistrus Isbrücker, Dolichancistrus Isbrücker, Leptoancistrus Meek & Hildebrand, and Lipopterichthys have not yet been discovered nor described, and since the new species does not exhibit the synapomorphies proposed by Schaefer (1986) for a monophyletic group that includes Chaetostoma, Dolichancistrus, Leptoancistrus, and Lipopterichthys, the second objective is to name and describe a new genus to accommodate the new species. Finally, although the taxonomic revision of the genera Chaetostoma and Cordylancistrus are projects in progress, the third objective is to provide an artificial key for the identification of these genera and Dolichancistrus, Leptoancistrus, Lipopterichthys, and Loraxichthys, based on current morphological knowledge, excluding Chaetostoma setosus Boulenger, which is treated as incertae sedis (Ballen & Vari 2012).…”

Description of Neblinichthys peniculatus, a new species of loricariid catfish from the río Paragua drainage of Venezuela

“…Names of plate rows follow Schaefer (1997). Specimens were sexed according to Ballen & Vari (2012) with mature females having a broad genital papilla with flaps around the aperture and males having a longer, pointed genital papilla; the male papilla corresponds with having hypertrophied odontodes on the snout. A principal components analysis for the morphometric data was performed using a covariate matrix and log-transformed measurements in JMP (Vers.…”