Dorsal spines (total): 1; Dorsal soft rays (total):
7; Anal soft rays: 12 - 16; Vertebrae: 42 - 45. Total
vertebrae including Weberian complex. Megalonema
amaxanthum is a medium-sized pimelodid with a
maximum length known to us of 106 mm SL. Dorsal profile
of head and nape convex from snout tip to vertical
at posterior nostril, then nearly straight to origin
of dorsal fin, scarcely convex along dorsal-fin base,
then less convex to posterior insertion of adipose
fin, and gently concave across caudal peduncle. Ventral
profile slanting convexly ventrally from snout tip
to end of gill region, slightly convex to straight
to pelvic-fin origin, abruptly stepped dorsad posterior
to pelvic girdle, then straight or convex onto analfin
base, slanting dorsally to caudal peduncle and slightly
concave along caudal peduncle. Colouration:
Head and body yellowish to tan in background colour.
Top and upper sides of head and body lightly to moderately
covered with small brownish chromatophores. Aquarium
Care: A tank of at least 3ft x 18ins x 18ins
with a medium water flow and weekly water changes.Diet:
Wormfoods, shellfish and other meaty or insect-based
foods. Remarks: For
more information on this species and genera read the
paper by Lundberg, J.G. and W.M. Dahdul, 2008 and
the catfish book by Steven Grant (2021) on Pims which
are referenced below.
Amazon River basin, Brazil, Guyana (Takutu River),
Peru, Bolivia, and probably Colombia and Ecuador.
Lundberg, J.G. and
2008. Two new cis-Andean species of the South American
catfish genus Megalonema allied to trans-Andean Megalonema
xantum, with description of a new subgenus (Siluriformes:
Pimelodidae). Neotrop. Ichthyol. 6(3):439-454. Froese, R. and D. Pauly. Editors.
2018. FishBase. World Wide Web electronic publication.
www.fishbase.org, ( 02/2018 ). Grant, Steven. Pims.
Pimelodidae, Heptapteridae and Pseudopimelodidae Catfishes.
ATS-Aquashop.de 2021 219p.