Usumacinta sea catfish

The Usumacinta sea catfish (Potamarius usumacintae) is a species of catfish in the family Ariidae. It was described by Ricardo Betancur-Rodriguez and Philip W. Willink in 2007. It is endemic to the Usumacinta River between Mexico and Guatemala. It reaches a maximum standard length of 59.5 cm.

The species epithet "usumacintae" refers to the Usumacinta River.