''Kutchicetus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of early whale of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Remingtonocetidae Remingtonocetidae is a diverse family of early aquatic mammals of the order Cetacea. The family is named after paleocetologist Remington Kellogg. Description Remingtonocetids have long and narrow skulls with the external nare openings located ...

that lived during Early-

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

(

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Midd ...

and

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

) in what is now the coastal border of

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

and

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

(, paleocoordinates ). It is closely related to ''

Andrewsiphius ''Andrewsiphius'' is an extinct remingtonocetid early whale known from the Eocene (Lutetian, ) of Gujarat and Kutch, India and Balochistan, Pakistan. Discovery and naming The first specimen was collected by who described it as mandibular f ...

'' with which it was synonymized by . proposed a new clade,

Andrewsiphiinae The Andrewsiphiinae is an extinct subfamily of early whales of the family Remingtonocetidae Remingtonocetidae is a diverse family of early aquatic mammals of the order Cetacea. The family is named after paleocetologist Remington Kellogg. ...

, for the two species. Later authors, however, still accept both as separate genera. ''Kutchicetus'' is smaller than other remingtonocetids, and probably is the smallest Eocene cetacean. With its extremely narrow snout, it resembles ''

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. It was named after naturalist Remington Kellogg. History ...

'' and ''

Dalanistes ''Dalanistes'' is an extinct genus of remingtonocetid early whale known from the late early Eocene (Lutetian, ) of Kutch, India and Punjab and Balochistan, Pakistan. ''Dalanistes'' is closely related to '' Remingtonocetus'' (the type genus ...

'', but its strong tail distinguishes it from both ''Remingtonocetus'' and ''Andrewsiphius''. Its limbs were short. Kutchicetus minimus

''Kutchicetus''' vertebral formula is 7, 15, 8, 4, 20–25. 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 of some land-living or semi-aquatic mammals, such as ''

Pachyaena ''Pachyaena'' (literally, "thick hyena") was a genus of heavily built, relatively short-legged mesonychids, early Cenozoic mammals that evolved before the origin of either modern hoofed animals or carnivores, and combined characteristics similar t ...

'' and

otters Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes wea ...

. ''Kutchicetus''' limbs and sacrum were probably weight-bearing and it probably swam using undulatory movements like modern otters and most likely ''

Ambulocetus ''Ambulocetus'' (Latin ''ambulare'' "to walk" + ''cetus'' "whale") is a genus of early amphibious cetacean from the Kuldana Formation in Pakistan, roughly 48 or 47 million years ago during the Early Eocene (Lutetian). It contains one species, ' ...

''.

This mode of locomotion represents a transitional stage in whale evolution.

Notes

References

* * * * Remingtonocetidae Transitional fossils Fossil taxa described in 2000 Prehistoric cetacean genera Extinct mammals of Asia {{paleo-whale-stub

See also

Notes

References