''Andrewsiphius'' is an extinct remingtonocetid early whale known from the

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'', ...

(

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 ...

, ) of

Gujarat Gujarat (, ) is a state along the western coast of India. Its coastline of about is the longest in the country, most of which lies on the Kathiawar peninsula. Gujarat is the fifth-largest Indian state by area, covering some ; and the ninth ...

and Kutch,

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

and

Balochistan Balochistan ( ; bal, بلۏچستان; also romanised as Baluchistan and Baluchestan) is a historical region in Western and South Asia, located in the Iranian plateau's far southeast and bordering the Indian Plate and the Arabian Sea coastline. ...

, Pakistan.

Discovery and naming

The first specimen was collected by who described it as mandibular fragments of '' Protocetus sloani''. described two new species, ''Andrewsiphius kutchensis'' and ''A. minor'' based on their previous material and new mandibular fragments. Later researchers interpreted the same mandibular specimens as belonging to ''Remintonocetus''. reinterpreted these specimens as fragments from

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

e, and determined that the described "confluence of the mandibular canals anteriorly" was in fact the narial passages. Gingerich et al. also determined that the variations in size among proposed species were within the normal variation for a single species and therefore attributed a number of referred specimens as belonging to ''Andrewsiphius sloani''. Gingerich et al. also noted that the type specimen of '' Kutchicetus minimus'' came from the same locality as ''A. sloani'' and that its distinctive small size was within the variation that could be expected for ''A. sloani'', and Gingerich et al. therefore included ''K. minimus'' into ''A. sloani''. Later authors, however, disagreed on this assignment and ''Kutchicetus'' is still accepted as a separate genus. named the type species for Dr Robert E. Sloan, Department of Geology, University of Minnesota.

Description

''Andrewsiphius'' is similar to but smaller than '' Kutchicetus'' (another remingtonocetid); synonymized them, and proposed a new subfamily, Andrewsiphiinae, for the two species. Later authors, however, still accept both as separate genera. ''Andrewsiphius'' and ''Kutchicetus'' share several characteristics not present in other remingtonocetids: an elongated snout that is higher than it is wide; foramina (small holes) on the tip of the snout suggesting the presence of whiskers; eyes located dorsally near the cranial midline, resulting in an appearance of a mammalian crocodile; and a very large

sagittal crest A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exception ...

overhanging the back of the skull. Other characteristics make them distinct: the second and third upper and lower premolars are double-rooted in ''Andrewsiphius'' but single-rooted in ''Kutchicetus''; the large diastemata in the former are absent the latter; and the tail vertebrae are more robust in ''Andrewsiphius''. ''Andrewsiphius'' is, compared to the remgintonocetids ''

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 ...

'', smaller, has a narrower rostrum, and smaller premolars separated by longer diastemata.

Notes

References

* * * * * {{Taxonbar, from=Q5675355 Remingtonocetidae Fossil taxa described in 1975 Prehistoric cetacean genera Eocene mammals of Asia