Protosirenidae

{{Short description|Extinct family of aquatic mammals}}

{{Automatic taxobox

| fossil_range = {{Fossil range|Middle Eocene|Late Eocene}}

| image = Protosiren_remains.png

| image_caption = The skeleton of Protosiren

| taxon = Protosirenidae

| authority = Sickenberg, 1934

| subdivision_ranks = Genera

| subdivision = *Ashokia

• Libysiren
• Protosiren

}}

Protosirenidae is an extinct primitive family of the order Sirenia.D. P. Domning, G. J. Heal, and S. Sorbi. 2017. Libysiren sickenbergi, gen. et sp. nov.: a new sirenian (Mammalia, Protosirenidae) from the middle Eocene of Libya. Journal of Vertebrate Paleontology 37(2):[https://www.tandfonline.com/doi/pdf/10.1080/02724634.2017.1299158 e1299158]{{cite web | url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=43290 | title=Fossilworks: Protosirenidae }}

Protosirenids are thought to have been amphibious quadrupeds, meaning that they spent their time both on land and in the water and had four legs.{{Cite book|url=http://cetus.ucsd.edu/sio133/PDF/BertaChap5.pdf|title=Sirenian and Other Marine Mammals: Evolution and Systematics|work=Marine Mammals: Evolutionary Biology |edition=2nd| last1=Berta|first1=Annalisa |last2=Sumich |first2=James |last3=Kovacs |first3=Kit |year=2005 |isbn=9780120885527 |pages=89–110|publisher=Elsevier Science |access-date=15 July 2018}}