What is "nanosiren"

Nanosiren garciae is an extinct sirenian mammal, a pygmy, tusked sea cow of the family Dugongidae, of the genus Nanosiren, living in warm shallow seas approximately 11.610—3.6 Ma during the Miocene, existing approximately . It is evolutionarily related to modern species of manatees and dugongs. The species is listed in the Paleobiology Database, funded by the Australian Research Council.

In their book, Ecology and Conservation of the Sirenia: Dugongs and Manatees, authors Helena Marsh, Thomas J. O'Shea and John E. Reynolds, III, describe the evolution of Nanosiren garciae from the Crenatosiren lineage, and argue that their small size allowed them access to very shallow water unavailable to larger sea mammals.