Babiacetus

{{Short description|Extinct protocetid early whale}}

{{Italic title}}

{{Use dmy dates|date=March 2021}}

{{Automatic taxobox

| name = Babiacetus

|image= Babiacetus IITR-SB 2512.jpg

|image_caption= lower jaw of Babiacetus

| fossil_range = Middle Eocene, {{Fossil range|47.8|40.4}}

| taxon = Babiacetus

| authority = {{Harvnb|Trivedy|Satsangi|1984}}

| subdivision_ranks = Species

| subdivision =

• B. indicus
  {{Harvnb|Trivedy|Satsangi|1984}}
• B. mishrai
  {{Harvnb|Bajpai|Thewissen|1998}}

}}

Babiacetus is an extinct genus of early cetacean that lived during the late Lutetian middle Eocene of India ({{Mya|47.8|40.4}}).{{Paleodb|53315|Babiacetus}}. Retrieved March 2013.{{Paleodb|collection|45592|Babia Hills}}. Retrieved April 2013.

It was named after its type locality, the Harudi Formation{{Paleodb|collection|76316|Harudi}}. Retrieved April 2013. in the Babia Hills ({{Coord|23.5|68.8|display=inline}}: paleocoordinates {{Coord|5.9|61.8|display=inline}}), Kutch District, Gujarat, India.

Babiacetus was named by {{Harvnb|Trivedy|Satsangi|1984}} in an abstract based on the specimen's type (GSI 19647, left and right dentaries with cheek teeth).{{Cite web

| title = Babiacetus | publisher = Palaeocritti

| url = http://www.palaeocritti.com/by-group/eutheria/cetacea/archaeoceti/babiacetus

| access-date = 27 March 2013}} Gingerich and colleagues found a skull (GSP-UM 3005, much of a skull and lower jaws) while collecting a skeleton of a new species of Protosiren (Protosiren sattaensis){{Harvnb|Gingerich|Arif|Bhatti|Raza|1995| loc=Introduction, p. 332}} in the Drazinda Formation ({{Coord|30.8|N|70.5|E|display=inline}}, paleocoordinates {{Coord|16.9|N|67.1|E|display=inline}}){{Paleodb|collection|28980|Bari Nadi 2}}. Retrieved April 2013. in the Sulaiman Range of Punjab, Pakistan. {{Harvnb|Gingerich|Arif|Bhatti|Raza|1995}} described both the original find and their new specimen.{{Harvnb|Bajpai|Thewissen|1998| pp=226–8}}

{{Harvnb|Bajpai|Thewissen|1998}} described B. mishrai from the specimen (RUSB 2512, a partial skull) collected in the Harudi Formation.{{Paleodb|63126|Babiacetus mishrai}}. Retrieved March 2013.

Babiacetus is one of the larger protocetids weighing about {{convert|830|kg|lb}}.{{Harvnb|Gingerich|Arif|Bhatti|Raza|1995| pp=348–53}}{{cite journal|last1=Gingerich |first1=Philip D. |last2=Arif |first2=M. |last3=Bhatti |first3=M. Akram |last4=Anwar |first4=M. |last5=Sanders |first5=William J. |year=1997 |title=Basilosaurus drazindai and Basiloterus hussaini, New Archaeoceti (Mammalia, Cetacea) from the Middle Eocene Drazinda Formation, with a Revised Interpretation of Ages of Whale-Bearing Strata in the Kirthar Group of the Sulaiman Range, Punjab (Pakistan) |url=https://deepblue.lib.umich.edu/bitstream/handle/2027.42/48652/ID519.pdf?sequence=2|journal=Contributions from the Museum of Paleontology, University of Michigan|volume=30 |issue=2 |pages=55–81}} Its hydrodynamic skull and pointed, anteroposteriorly (front-back) oriented incisors are typical of archaeocetes. A densely ossified auditory bulla and large mandibular canal indicate it was adapted for hearing in water.{{Harvnb|Gingerich|Arif|Bhatti|Raza|1995| pp=354–5}} Babiacetus differs from pakicetids and ambulocetids (more primitive families) by the large mandibular foramen and a medially concave ascending ramus; distinct from remingtonocetids and basilosaurids (more derived families) by the single-cusped trigonid and talonid on the lower molars. Its long synostotic (fused) mandibular symphysis, which reaches as far back as P₂, distinguishes it from Pappocetus and Georgiacetus (other protocetids). Its auditory bulla is more narrow than Rodhocetus'. Babiacetus lacks the prominent molar protocone present in Indocetus.{{Harvnb|Williams|1998| pp=12–13}}

The anterior premolars are large.

Its large size as well as robust teeth suggest that it fed on larger fishes or aquatic vertebrates, or both. To date, only cranial remains have been found, hence nothing is known of Babicetus' mode of locomotion or degree of aquatic adaptation.

The mandible is longer in B. indicus than in B. mishrai, and P₁ is single-rooted in the former but double-rooted in the latter. The diastemata between P₁ and P₄ in B. indicus is absent in B. mishrai. B. indicus has larger cheek teeth and a larger M₃.