This species is the only member of its genus, Oxyzygonectes, and the subfamily Oxyzygonectinae.

[3] This fish species is found in Pacific drainages in Nicaragua, Costa Rica, and Panama.

The dorsal and anal fins are posteriorly placed just before the caudal peduncle and well behind the midbody.

They are found in rivers of low elevation, up to 15 metres (50 ft) above sea level.

[2] The fish is named in honor of John Melmoth Dow (1827–1892), of the Panama Railroad Company, who in addition to being a ship captain, he was an amateur naturalist who presented the type specimen to the British Museum.