Dorsal soft rays (total): 5 - 6; Anal soft rays: 21
- 26; Vertebrae: 37 - 41. The combination of the presence
of a dorsal fin with an ossified spinelet and the
presence of pectoral and dorsal-fin spines distinguishes
the species of Cetopsidium from all other
genera in the Cetopsinae. The possession of a lateral
line extending to over the posterior portion of the
base of the anal fin but falling short of the caudal
peduncle is also unique to Cetopsidium within
the Cetopsinae. Sexual Dimorphism.
Presumed mature males of Cetopsidium pemon
have the first ray of the dorsal and pectoral fins
extending past the fin margin as a distinct filament
contrary to the absence of such a prolongation on
these rays in females and immature males. Mature males
of the species also have the anal-fin margin broadly
convex rather than straight as in females and immature
Caroni, Caura and Meta river basins, Venezuela and
Colombia, Branco River, Brazil. Type locality:
Venezuela. Bolivar: Río Caroni, at mouth of
Río Claro (7º54'45"N, 63º02'35"W).
22-28°c (71-83°f )
Ferraris, C.J. Jr.,
2007. Checklist of catfishes, recent and fossil (Osteichthyes:
Siluriformes), and catalogue of siluriform primary
types. Zootaxa 1418:1-628. 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.