sentences:  Three subspecies are currently recognized; "P. s. striatus", the broad-striped dwarf siren, "P. s. lustricolus", the Gulf Hammock dwarf siren, and "P. s. spheniscus", the slender dwarf siren.The northern dwarf siren is the smallest siren known, at only .Like other members of the Sirenidae, the northern dwarf siren is aquatic and gilled throughout its life.