Protocetid cetaceans (Mammalia) from the Eocene of India
Cetacea; India; hearing; Paleontology; morphology; origin; pakistan; Eocene; locomotor evolution; Mammalia; middle eocene; earliest cetaceans; ambulocetidae; early whales; kutch; New genus; New species
Protocetid cetaceans were first described from the Eocene of India in 1975, but many more specimens have been discovered since then and are described here. All specimens are from District Kutch in the State of Gujarat and were recovered in deposits approximately 42 million years old. Valid species described in the past include Indocetus ramani, Babiacetus indicus and B. mishrai. We here describe new material for Indocetus, including lower teeth and deciduous premolars. We also describe two new genera and species: Kharodacetus sahnii and Dhedacetus hyaeni. Kharodacetus is mostly based on a very well preserved rostrum and mandibles with teeth, and Dhedacetus is based on a partial skull with vertebral column. The Kutch protocetid fauna differs from the protocetid fauna of the Pakistani Sulaiman Range, possibly because the latter is partly older, and/or because it samples a different environment, being located on the trailing edge of the Indian Plate, directly exposed to the Indian Ocean.
Bajpai S; Thewissen J G M
Palaeontologia Electronica
2014
2014
Journal Article or Conference Abstract Publication
n/a
The origin and early evolution of whales: macroevolution documented on the Indian Subcontinent
Cetacea; India; evolution; energetics; Life Sciences & Biomedicine - Other Topics; artiodactyls; Eocene; pakistan; whales; cetaceans; Eocene; cetartiodactyla; locomotor evolution; dolphins; middle; semiaquatic mammals; underwater hearing
The origin of whales (order Cetacea) from a four-footed land animal is one of the best understood examples of macroevolutionary change. This evolutionary transition has been substantially elucidated by fossil finds from the Indian subcontinent in the past decade and a half. Here, we review the first steps of whale evolution, i.e. the transition from a land mammal to obligate marine predators, documented by the Eocene cetacean families of the Indian subcontinent: Pakicetidae, Ambulocetidae, Remingtonocetidae, Protocetidae, and Basilosauridae, as well as their artiodactyl sister group, the Raoellidae. We also discuss the influence that the excellent fossil record has on the study of the evolution of organ systems, in particular the locomotor and hearing systems.
Bajpai S; Thewissen J G M; Sahni A
Journal of Biosciences
2009
2009-11
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/s12038-009-0060-0" target="_blank" rel="noreferrer noopener">10.1007/s12038-009-0060-0</a>
Postcranial Morphology And Locomotion Of The Eocene Raoellid Indohyus (artiodactyla: Mammalia)
Artiodactyla; bone-density; Cetacea; cetartiodactyla; earliest cetaceans; early whales; evolution; fur seals; india; Indohyus; Life Sciences & Biomedicine - Other Topics; origin; osteosclerosis; pakistan; Paleontology; postcrania; Raoellidae; sea lions
Cooper L N; Thewissen J G M; Bajpai S; Tiwari B N
Historical Biology
2012
1905-07
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1080/08912963.2011.624184" target="_blank" rel="noreferrer noopener">10.1080/08912963.2011.624184</a>
Anthracobunids from the middle eocene of India and pakistan are stem perissodactyls.
Animals; *Fossils; India; Dugong; Elephants; Pakistan
Anthracobunidae is an Eocene family of large mammals from south Asia that is commonly considered to be part of the radiation that gave rise to elephants (proboscideans) and sea cows (sirenians). We describe a new collection of anthracobunid fossils from Middle Eocene rocks of Indo-Pakistan that more than doubles the number of known anthracobunid fossils and challenges their putative relationships, instead implying that they are stem perissodactyls. Cranial, dental, and postcranial elements allow a revision of species and the recognition of a new anthracobunid genus. Analyses of stable isotopes and long bone geometry together suggest that most anthracobunids fed on land, but spent a considerable amount of time near water. This new evidence expands our understanding of stem perissodactyl diversity and sheds new light on perissodactyl origins.
Cooper Lisa Noelle; Seiffert Erik R; Clementz Mark; Madar Sandra I; Bajpai Sunil; Hussain S Taseer; Thewissen J G M
PloS one
2014
1905-7
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1371/journal.pone.0109232" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0109232</a>
The Anterior Dentition Of Sivapithecus-parvada, With Comments On The Phylogenetic Significance Of Incisor Heteromorphy In Hominoidea
Anthropology; clade; dentition; east-africa; evolution; Evolutionary Biology; hominids; hominoid phylogenetics; incisors; kenya; middle miocene; miocene hominoid; orangutan; origin; pakistan; pongo; sivapithecus; specimens
A premaxillary fragment of Sivapithecus parvada preserving the germs of the right central and lateral incisors is described. The specimen was recovered in situ during excavation at locality Y311 in the upper Nagri Formation (ca. 9.2 m.y.a.) of the Siwalik Sequence, Potwar Plateau, Pakistan. The central incisor is approximately 35% larger than the next largest Sivapithecus incisor, in keeping with the very large size of S. parvada compared to other Sivapithecus species, and is exceptionally long mesiodistally in relation to its breadth. It is also morphologically distinct, having a sharply angled distal margin and a distinct lingual tubercle. However, previous descriptions of Sivapithecus upper central incisors as having a continuous lingual shelf are in some cases erroneous and ignore the morphological variation present in the sample. In several features of anterior tooth size, morphology and proportionality, S. parvada resembles Pongo more than do other species of Sivapithecus. The I1/I2 length ratio of the new specimen is 2.12, the largest size disparity reported for any fossil catarrhine, and greater than any single value in a large sample of Pongo pygmaeus. Very great size disparity between upper central and lateral incisors is widely considered to be a synapomorphy of the orang-utan lineage. We conclude, however, that descriptions of upper incisor size heteromorphy in Pongo have in general been exaggerated and have failed to recognize substantial differences in this character between Bornean and Sumatran orang-utans. We further conclude, based on examination of a variety of Miocene hominoids and other Miocene catarrhine primates, that the character of I1/I2 proportionality has little if any phylogenetic utility within Hominoidea.
Kelley J; Anwar M; McCollum M A; Ward S C
Journal of Human Evolution
1995
1995-06
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1006/jhev.1995.1039" target="_blank" rel="noreferrer noopener">10.1006/jhev.1995.1039</a>
Middle Eocene Prosimian Primate From The Subathu Group Of Kalakot, Northwestern Himalaya, India
anthropoid primate; china; dentition; myanmar; origin; pakistan; province; Science & Technology - Other Topics; thailand
An upper molar tooth of a possibly new but unnamed prosimian primate (Mammalia, Primates) is described from the Middle Eocene, in the uppermost part of the Subathu Group exposed east of Babbian Gala near Kalakot (northwestern Outer Himalaya) in the Rajauri District, Jammu and Kashmir, India. To the best of our knowledge, this is the first pre-Siwalik primate from India and the only primate tooth identified thus far in a remarkably rich and varied land mammal fauna known from the red beds of the Subathu Group. Its occurrence is significant, as the Eocene primates of the Indian subcontinent are important for understanding the early primate radiation in Asia.
Kumar K; Hamrick M W; Thewissen J G M
Current Science
2002
2002-11
Journal Article or Conference Abstract Publication
n/a
Enigmatic New Ungulates From The Early Middle Eocene Of Central Anatolia, Turkey
basin; evolution; mammalia; oligocene; osteology; pakistan; Paleontology; position
Maas M C; Thewissen J G M; Sen S; Kazanci N; Kappelman J
Journal of Vertebrate Paleontology
2001
2001-08
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1671/0272-4634(2001)021%5B0578:enufte%5D2.0.co;2" target="_blank" rel="noreferrer noopener">10.1671/0272-4634(2001)021%5B0578:enufte%5D2.0.co;2</a>
Cranial anatomy of Pakicetidae (Cetacea, Mammalia)
artiodactyls; eocene; evolution; hearing; origin; pakistan; Paleontology; whales
The skulls and isolated tympanics are described for the earliest whales, pakicetids, from the H-GSP Locality 62 in the Ganda Kas area in Northern Pakistan. Currently three pakicetid genera are known: Pakicetus, Ichthyolestes, and Nalacetus. Ichthyolestes is smaller than the two other genera. Nalacetus and Pakicetus are similar in size, but morphologically different. Pakicetids have a nasal opening at the tip of the rostrum. Their palate retains an incisive foramen. This study reveals three characters of the cranial anatomy useful for systematic analyses. In pakicetids the orbits are orientated dorsally, and there is no supraorbital shield. The dorsal orientation of the orbits is diagnostic for the family, and the lack of supraorbital shield distinguishes pakicetids, ambulocetids, and remingtonocetids from the other Eocene archaeocetes. The intertemporal region of the pakicetid skull is very narrow, a feature that also occurs in many other Eocene cetaceans. The tympanic, which is the most abundant cranial bone (more than 30 specimens) in the pakicetid collections from H-GSP Locality 62, can be used to distinguish the species of pakicetids. In Ichthyolestes, the tympanic bulla is of the same absolute size as in Pakicetus, hence relatively larger, and the tympanic bulla of Nalacetus is larger than either of these. Morphologically, the tympanic bullae differ between the genera, and on the basis of these morphologies it is possible to recognize a fourth species of pakicetid at this locality.
Nummela S; Hussain S T; Thewissen J G M
Journal of Vertebrate Paleontology
2006
2006-09
Journal Article
<a href="http://doi.org/10.1671/0272-4634(2006)26%5B746:caopcm%5D2.0.co;2" target="_blank" rel="noreferrer noopener">10.1671/0272-4634(2006)26%5B746:caopcm%5D2.0.co;2</a>
Whales originated from aquatic artiodactyls in the Eocene epoch of India.
*Phylogeny; *Whales/anatomy & histology/classification/physiology; Animals; ARTIODACTYLA; BICUSPIDS; CETACEA; EOCENE stratigraphic geology; India; INDIA; MAMMALOGICAL research; Pakistan; Time Factors; UNGULATES; WHALES
Although the first ten million years of whale evolution are documented by a remarkable series of fossil skeletons, the link to the ancestor of cetaceans has been missing. It was known that whales are related to even-toed ungulates (artiodactyls), but until now no artiodactyls were morphologically close to early whales. Here we show that the Eocene south Asian raoellid artiodactyls are the sister group to whales. The raoellid Indohyus is similar to whales, and unlike other artiodactyls, in the structure of its ears and premolars, in the density of its limb bones and in the stable-oxygen-isotope composition of its teeth. We also show that a major dietary change occurred during the transition from artiodactyls to whales and that raoellids were aquatic waders. This indicates that aquatic life in this lineage occurred before the origin of the order Cetacea.
Thewissen J G M; Cooper Lisa Noelle; Clementz Mark T; Bajpai Sunil; Tiwari B N
Nature
2007
2007-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1038/nature06343" target="_blank" rel="noreferrer noopener">10.1038/nature06343</a>
FOSSIL EVIDENCE FOR THE ORIGIN OF AQUATIC LOCOMOTION IN ARCHAEOCETE WHALES
eocene; pakistan; Science & Technology - Other Topics
Recent members of the order Cetacea (whales, dolphins, and porpoises) move in the water by vertical tail beats and cannot locomote on land. Their hindlimbs are not visible externally and the bones are reduced to one or a few splints that commonly lack joints. However, cetaceans originated from four-legged land mammals that used their limbs for locomotion and were probably apt runners. Because there are no relatively complete limbs for archaic archaeocete cetaceans, it is not known how the transition in locomotory organs from land to water occurred. Recovery of a skeleton of an early fossil cetacean from the Kuldana Formation, Pakistan, documents transitional modes of locomotion, and allows hypotheses concerning swimming in early cetaceans to be tested. The fossil indicates that archaic whales swam by undulating their vertebral column, thus forcing their feet up and down in a way similar to modern otters. Their movements on land probably resembled those of sea lions to some degree, and involved protraction and retraction of the abducted limbs.
Thewissen J G M; Hussain S T; Arif M
Science
1994
1994-01
Journal Article
<a href="http://doi.org/10.1126/science.263.5144.210" target="_blank" rel="noreferrer noopener">10.1126/science.263.5144.210</a>
Evolution of dental wear and diet during the origin of whales
artiodactyls; Biodiversity & Conservation; carbon-isotope discrimination; cetaceans; Environmental Sciences & Ecology; Evolutionary Biology; mammalia; middle eocene; pakistan; Paleontology; photosynthesis; seagrasses; tooth enamel; transitions
Dental morphology changes dramatically across the artiodactyl-cetacean transition, and it is generally assumed that this reflects the evolutionary change from herbivory and omnivory to carnivory. To test hypotheses regarding tooth function and diet, we studied size and position of wear facets on the lower molars and the stable isotopes of enamel samples. We found that nearly all investigated Eocene cetaceans had dental wear different from typical wear in ungulates and isotope values indicating that they hunted similar prey and processed it similarly. The only exception is the protocetid Babiacetus, which probably ate larger prey with harder skeletons. The closest relative of cetaceans, the raoellid artiodactyl Indohyus, had wear facets that resemble those of Eocene cetaceans more than they do facets of basal artiodactyls. This is in spite of Indohyus's tooth crown morphology, which is unlike that of cetaceans, and its herbivorous diet, as indicated by stable isotopes. This implies that the evolution of masticatory function preceded that of crown morphology and diet at the origin of cetaceans.
Thewissen J G M; Sensor J D; Clementz M T; Bajpai S
Paleobiology
2011
2011
Journal Article
n/a
The early radiations of cetacea (Mammalia): Evolutionary pattern and developmental correlations
archaeocete; artiodactyls; development; Environmental Sciences & Ecology; evolution; Evolutionary Biology; feet; fossil record; India; locomotor evolution; marine mammal; middle eocene; origin; pakistan; Stenella attenuata; time; whales
The origin and early evolution of Cetacea (whales, dolphins, and porpoises) is one of the best examples of macroevolution as documented by fossils. Early whales are divided into six families that differ greatly in their habitats, which varied from land to freshwater, coastal waters, and fully marine. Early cetaceans lived in the Eocene (55-37 million years ago), and they show an enormous morphological diversity. Toward the end of the Eocene the modem cetacean body plan originated, and this body plan remained more or less the same in the subsequent evolution. It is possible that some aspects of this body plan are rooted in constraints that are dictated by cetacean embryologic development and controlled by genes that affect many organ systems at once. It may be possible to use a study of patterns of correlations among morphological traits to test hypotheses of developmental links among organ systems.
Thewissen J G M; Williams E M
Annual Review of Ecology and Systematics
2002
2002
Journal Article
<a href="http://doi.org/10.1146/annurev.ecolysis.33.020602.095426" target="_blank" rel="noreferrer noopener">10.1146/annurev.ecolysis.33.020602.095426</a>
New Kohatius (Omomyidae) from the Eocene of Pakistan.
*Primates; Animals; Pakistan; Tooth/*ultrastructure
Thewissen J G; Hussain S T; Arif M
Journal of human evolution
1997
1997-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1006/jhev.1996.0115" target="_blank" rel="noreferrer noopener">10.1006/jhev.1996.0115</a>