Cetopsis amphiloxa can be distinguished from
all of its congeners by the combination of the presence
of an eye, the conical teeth on the vomer and dentary,
the rounded posterior nares which is distinctly separated
from the contralateral nares by a distance greater
than the width of posterior nares, the absence of
a dark humeral spot, the presence of very small rather
than eye-sized or larger spots on the lateral and
dorsal surfaces of the body, the lack of a concentration
of dark pigmentation at the base of the dorsal fin,
the lack of a band of dark pigmentation along the
distal portion of the anal fin, the possession of
29 to 33 total anal-fin rays, 23 to 28 branched anal-fin
rays, 10 to 12 precaudal vertebrae, 31 to 33 caudal
vertebrae, 41 to 43 total vertebrae, 8, or rarely,
9 pectoral-fin rays, and the lack of a concentration
of dark pigmentation basally on the dorsal fin. Habitat:
Known from the northern portions of the Rio San Juan
basin and southern sections of the adjoining Rio Atrato
basin, both in western Colombia, the Rio Patia basin
of southwestern Colombia, and the rivers of northwestern
This species has localised threats that may be causing
declines in the extent and quality of its habitat.
However, it is widely distributed and is present in
at least one protected area. Hence it is listed as
Least Concern (IUCN 2016).
Patía, upper San Juan and Atrato River basins,
Pacific versant, western Colombia, and rivers of northwestern
Ecuador. Type locality: Creek near
San Lorenzo, [Río] Patía basin, Colombia.
22-28°c (71-83°f )
Arguello, P. &
Sanchez-Duarte, P. 2016. Cetopsis amphiloxa.
The IUCN Red List of Threatened Species 2016. Ferraris, C.J. Jr., 2007. Checklist
of catfishes, recent and fossil (Osteichthyes: Siluriformes),
and catalogue of siluriform primary types. Zootaxa
1418:1-628. Froese, R. and D. Pauly. Editors.
2021. FishBase. World Wide Web electronic publication.
www.fishbase.org, ( 06/2021 ). Vari, R. P., C. J. Ferraris Jr. & M. C.
C. de Pinna. 2005. The Neotropical whale
catfishes (Siluriformes: Cetopsidae: Cetopsinae),
a revisionary study. Neotropical Ichthyology 3:127-238.