Taxonomic revision of Hypostomus albopunctatus (Siluriformes: Loricariidae) reveals a new piece of the Hypostomus jigsaw in the upper Rio Paraná basin

Abstract

Hypostomus albopunctatus was described from the Rio Piracicaba, a tributary of the Rio Tietê, upper Rio Paraná basin. Nevertheless, specimens attributed to this species are commonly found throughout other river systems in the upper Rio Paraná basin and present varying degrees of morphological variation. A taxonomic review of H. albopunctatus based on large series of specimens from many localities throughout the upper Rio Paraná basin was carried out. Results support H. lexi, H. niger and H. scaphyceps as junior synonyms. Hypostomus albopunctatus differs from all congeners except H. heraldoi by having pectoral‐fin spine equal to or shorter than pelvic‐fin spine (v. longer); it differs from H. heraldoi by having white or light yellow spots on the body and fins (v. dark brown or black spots). Despite conspicuous variation related to the shape and size of the spots and snout morphology, both spot and snout patterns overlapped among the examined populations, thus this variation was inferred to be intraspecific within a widely distributed H. albopunctatus.

The rediscovery of Pimelodella longipinnis (Borodin, 1927), an enigmatic Atlantic Rainforest catfish species from Southeastern Brazil (Siluriformes: Heptapteridae)

“…In situ behavior was registered with a stationary camera Panasonic Lumix DMC-TS20 on three occasions, in four locations, during 15 minutes in the afternoon. Categorization of observed behavior follows Wilson & Roys (1994) and Morgan & Fine (2020).…”

“…Furthermore, a pectoral brush (pectoral-fin brush along the side of the opponent, either parallel or antiparallel), behavior described for the blue catfish Ictalurus furcatus (Ictaluridae) (Morgan & Fine, 2020) was also observed. Described behaviors are probably related to territory dispute (Wilson & Roys, 1994) and can be observed in the video provided in the Supplementary material.…”

“…Subaquatic observations (Supplementary Material S1) revealed conspecific agonistic behaviors between P. longipinnis individuals. The observed behaviors are according to the following categories described for the channel catfish Ictalurus punctatus (Ictaluridae) (Wilson & Roys, 1994): head thrust (abrupt swing of head, laterally, against other fish), head wag (series of head thrusts), tail beat (tail thrusts as a means of displacement another fish), and tail thrust (powerful lateral swing of the tail). Furthermore, a pectoral brush (pectoral-fin brush along the side of the opponent, either parallel or antiparallel), behavior described for the blue catfish Ictalurus furcatus (Ictaluridae) (Morgan & Fine, 2020) was also observed.…”

A taxonomically complex catfish group from an underrepresented geographic area: Systematics and species limits in Hypostomus Lacépède, 1803 (Siluriformes, Loricariidae) from Eastern South America

“…These issues increase taxonomic uncertainties, leading to cases of synonymy, as verified in Hypostomus albopunctatus (Regan 1908), whose morphological reassessment across its entire geographic distribution resulted in the synonymization of Hypostomus lexi, Hypostomus niger, and Hypostomus scaphyceps (Zawadzki et al, 2019b).…”

“…These issues increase taxonomic uncertainties, leading to cases of synonymy, as verified in Hypostomus albopunctatus (Regan 1908), whose morphological reassessment across its entire geographic distribution resulted in the synonymization of Hypostomus lexi , Hypostomus niger , and Hypostomus scaphyceps (Zawadzki et al, 2019b). Similarly, the molecular delimitation of species has been largely inaccurate, encompassing several cases of large and heterogeneous groups (Jardim de Queiroz et al, 2020; Montoya‐Burgos, 2003).…”