Adelphesiren[1] Habrosaurus, meaning "graceful lizard", is an extinct genus of prehistoric salamanders, and the oldest known member of the family Sirenidae.

Two species are known, H. prodilatus from the middle Campanian Dinosaur Park Formation of Alberta,[1] and H. dilatus from the late Maastrichtian and Paleocene of western North America.

[3] H. prodilatus possessed chisel-like teeth, while H. dilatus had bulkier crowns.

[1] Habrosaurus is a sister taxa to both Pseudobranchus and Siren[1] which are the only genera in the family Sirenidae.

Sirenids are classified by their neotenous traits (complete lack of hindlimbs and external gills in both larval and adult states).