This genus was previously placed
in its own family of Ageneiosidae and you can still
find some publications that still follow this line.
Description: Anal soft rays: 34 - 40; Vertebrae:
46 - 51. Body naked and elongated. Head is pointed
and depressed at the top. Mouth is big and wide. The
lateral eyes are situated along the level of the mouth,
ensuring a vision above and below. Exhibits sexual
dimorphism, like A. dentatus. The first ray
of the dorsal fin is very long and has pointed spines.
Habitat: Prefers rivers in overgrown backwaters
where the current is not too strong. Diet:
Feeds on fish and crustaceans. Its flesh is esteemed
for its very fine flavour. Is reported to be nocturnal.
Frequently captured with nets, the males are difficult
to release from the nets because of its strong dorsal
spine bordered with denticles. Breeding:
During reproduction, the mandibular barbels and dorsal
spine of the male change, and a copulatory organ appears
at the anterior level of the anal fin. Fertilisation
is internal, the female being capable of keeping the
spermatozoids inserted in the epithelium of her genital
tract. Aquarium Care: As per this
genera they will be fine as juveniles, but as they
mature they become predatory so would need to be kept
with fish that are not too small. A large tank would
be needed with plenty of swimming space. Remarks:
The species Ageneiosus marmoratus is now
considered a junior synonym of A. inermis (Ribeiro,
F. R. V. et. al 2017).
South America:Widely distributed in South America, east
of the Andes. Type locality: Surínam.
Froese, R. and D. Pauly.
Editors. 2009.FishBase. World Wide Web electronic
publication. www.fishbase.org, version (11/2011). Boujard, T., M. Pascal, F.J. Meunier and P.-Y.
Le Bail 1997 Poissons de Guyane. Guide écologique
de l'Approuague et de la réserve des Nouragues.
Institut National de la Recherche Agronomique, Paris,
219 p. Le Bail, P.-Y., P. Keith and P. Planquette
2000 Atlas des poissons d'eau douce de Guyane
(tome 2, fascicule II). Publications scientifiques
du Muséum national d'Histoire naturelle, Paris:307
p. Ferraris, C.J. Jr., 2007. Checklist
of catfishes, recent and fossil (Osteichthyes: Siluriformes),
and catalogue of siluriform primary types. Zootaxa
1418:1-628. Ribeiro, F. R. V., L. H. Rapp Py-Daniel and
S. J. Walsh 2017 (9 Feb.) Taxonomic revision
of the South American catfish genus Ageneiosus (Siluriformes:
Auchenipteridae) with the description of four new
species. Journal of Fish Biology. Max Pedley. Pers comm. 2020.