Ageneiosus intrusus differs from its congeners,
pardalis and A.
by having an upper jaw that overhangs the lower jaw
by a distance greater than the hor-izontal eye diameter
(v. less than the horizontal eye diameter). Ageneiosus
intrusus differs from A. pardalis by
having a reduced and ossified gas bladder (v. large,
non-ossfied gas bladder) and by having epaxial musculature
that covers the tympanic region (v.tympanic region
translucent, not concealed by epaxial musculature).
Ageneiosus intrusus differs from A. ucayalensis
by having a robust pectoral spine, rigid and sharp(v.
pectoral spine slender, becoming progressively segmented
in individuals larger thanabout 100 mm LS) and fewer
vertebrae (49 v. 53–55). Ageneiosus intrusus
differs from A.
by having more anal-?n rays (37– 46, mode=42
v. 32 –38, mode =34–35). Ageneiosus
intrusus differs from A.
polystictus and A. vittatus
by having a deeply forked caudal ?n (v. caudal ?n
strongly emarginate to truncate). Ageneiosus intrusus
differs from A. apiaka by having more gill
rakers on the firstbranchial arch (15– 20, mode
=18 v. 13–16, mode =14) and by usually having
a dark band on the distal margin of the caudal fin
rays (v. distal margin of caudal fin rays hyaline).
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. Sexual Differences:Males posses a genital papilla and when sexually
mature have an enlargedand curved
extension to the dorsal fin spine. They also grow
thickened barbels to grasp the females with. These
differences revert back to normal when not in season.
Diet: Meat based. Remarks:
This genus was previously placed in its own family
of Ageneiosidae and you can still find some publications
that still follow this line. Comments:
Specimens from the Orinoco River have an elongate
premaxilla, but it overhangs the dentary by a distance
slightly shorter than that of specimens from the Amazon
River basin. These specimens are designated as non-types
and no other differences in morphometric or meristic
features were found when compared with specimens fromthe
Amazon River basin. Etymology: The
specifc epithet intrusus, from Latin, meaning intruded,
in reference to the pre-maxilla projecting beyond
the dentary, a distinctive character of the new species.
South America:Middle and lower Amazon River and probably
the Orinoco River. Type Locality:
Rio Solimões, Paraná do Rei, Amazonas,
Ribeiro, Frank Rapp
Py-Daniel, Lúcia Walsh, Stephen 2017/02/01.
Taxonomic revision of the South American catfish genus
Ageneiosus (Siluriformes: Auchenipteridae) with the
description of four new species: taxonomic revision
of ageneiosus 90 10.1111/jfb.13246 Journal of Fish