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Animal Database
Remingtonocetidae
Kutchicetus minimus
Kutchicetus minimus skeleton
Estimated Population 0
Scientific Classification
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Cetacea
Family †Remingtonocetidae
Conservation Status
EXSpecies
Extinct

Remingtonocetidae is a diverse family of early aquatic mammals of the order Cetacea, endemic to the coastline of the ancient Tethys Ocean during the Eocene (present-day Pakistan and India). Living from 55.8—48.6 mya, they existed for approximately 7.2 million years. The name of the family was derived from the genus Remingtonocetus which was named after paleocetologist Remington Kellogg.

Description[]

Remingtonocetids have long and narrow skulls with the external nare openings located on the front of the skull. Their frontal shields are narrow and their orbits small. Their mouth has a convex palate and an incompletely fused mandibular symphysis. The anterior teeth are flattened mediolaterally, making them appear shark-like.

In the postcranial skeleton, the cervical vertebrae are relatively long and the sacrum is composed of four vertebrae of which at least three are fused. The acetabular notch is narrow or closed and on the femoral head the fovea is absent.

Cranial fossils are common but dental remains are rare. The postcrania morphology is based entirely on a single specimen of Kutchicetus which was small and had a long and muscular back and tail. Perhaps Remintonocetids swam like the South American giant otter which swims with its long flat tail.

With long and low bodies, relatively short limbs, their elongated rostrum, Remingtonocetids looked like mammalian crocodiles, more so than Ambulocetus. They could both walk on land and swim in the water and most likely lived in a near-shore habitat. At least one genus, Dalanistes, had a marine diet.

Remingtonocetids are often found in association with catfish and crocodilians, as well as protocetid whales and sirenians. They were probably independent of freshwater.

Genus Remingtonocetus[]

Remingtonocetus is an extinct genus of early cetacean freshwater aquatic mammals of the family Remingtonocetidae endemic to the coastline of the ancient Tethys Ocean during the Eocene between 48.6 to 37.2 million years ago. It was named after naturalist Remington Kellogg. Remingtonocetus had four working and usable limbs, a slender whale-like body with long tail and slender, hydrodynamic head.

Genus Attockicetus[]

Attockicetus is an extinct genus of cetacean which existed in Pakistan during the Eocene period. The type species is Attockicetus praecursor.

Genus Dalanistes[]

Dalanistes is an extinct genus of early carnivorous freshwater aquatic mammals of the family Remingtonocetidae endemic to the coastline of the ancient Tethys Ocean during the Eocene living about 47 mya. Dalanistes had four working and usable limbs, a slender whale-like body with long tail and slender, hydrodynamic head. Three specimens were found in north central Pakistan and near the coastal border of Pakistan and India.

Genus Kutchicetus[]

Kutchicetus ("Kutch whale") is an extinct genus of early whale of the family Remingtonocetidae that lived during Early-Middle Eocene (Lutetian and Ypresian, 55.8 to 40.4 million years ago) in what is now the coastal border of Pakistan and India (23.7°N 68.7°E, paleocoordinates 6.0°N 61.8°E). It is closely related to Andrewsiphius with which it was synonymized by Gingerich et al. 2001.

Kutchicetus is smaller than other remingtonocetids, less than half the size of Andrewsiphius minor, and probably is the smallest Eocene cetacean. With its extremely narrow snout, it resembles Remingtonocetus and Dalanistes, but its strong tail distinguishes it from both Remingtonocetus and Andrewsiphius. Its limbs were short.

Its four fused sacral vertebrae were probably articulated to the hip bone and the numerous tail vertebrae were robust and elongated in contrast to its short and relatively gracile limb bones. This morphology suggests that the tail played an important role in its locomotion, yet the proportions of the caudal-most vertebrae indicates Kutchicetus did not have flukes.

Kutchicetus' vertebral proportions are unlike those of any other cetaceans but similar to those a some land-living or semi-aquatic mammals, such as Pachyaena and otters. Kutchicetus' limbs and sacrum were probably weight-bearing and it probably swam using undulatory movements like modern otters and most likely Ambulocetus. This mode of locomotion represents a transitional stage in whale evolution.

Genera[]

Family Remingtonocetidae

Genus Andrewsiphius 
Genus Attockicetus
 A. praecursor
Genus Dalanistes 
 D. ahmedi
Genus Kutchicetus 
 K. minimus
Genus Remingtonocetus
 R. harudiensis
 R. domandaensis

Gallery[]

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