SciadeoidesEigenmann & Eigenmann, 1888 Leiarius is a genus of long-whiskered catfishes native to South America.

There are currently four recognized species in this genus:[1] L. marmoratus can reach a little more than 100 centimetres (39 in) TL and has a maximum published weight of about 12 kilograms (26 lb).

[5] As both of these species grow, their barbels will shorten in proportion to their size, and the caudal fin lobes, which are rounded in the young, become much more pointed.

[4][5] As L. marmoratus grows older, it darkens and its dark spots develop into a marbled pattern.

This species prefers to lay over rock and tree trunks during the day, being more active at sunrise, sunset, and night.