The origin and early evolution of whales: macroevolution documented on the Indian Subcontinent

@article{Bajpai2009TheOA,
  title={The origin and early evolution of whales: macroevolution documented on the Indian Subcontinent},
  author={Sunil Bajpai and J. G. M. Thewissen and Ashok Sahni},
  journal={Journal of Biosciences},
  year={2009},
  volume={34},
  pages={673-686}
}
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… 

On the origin of Cetartiodactyla: Comparison of data on evolutionary morphology and Molecular biology

TLDR
Molecular similarity between Hippopotamidae and Cetacea is evidence of common origin of Artiodactyla andCetacea and adaptation to aquatic environment.

Ecological evolution of early Cetartiodactyla and reconstruction of its missing initial link

The analysis of biodiversity and ecological evolution of Eocene Cetartiodactyla against the background of changes in the biosphere, biota, and paleogeography has provided a model for the origin,

Resolving the relationships of Paleocene placental mammals

TLDR
The largest cladistic analysis of Paleocene placentals to date is presented, from a data matrix including 177 taxa (130 of which are Palaeogene) and 680 morphological characters, and supports an Atlantogenata–Boreoeutheria split at the root of crown Placentalia, the presence of phenacodontids as closest relatives of Perissodactyla, and the validity of Euungulata.

Middle Eocene (Bartonian) vertebrate fauna from Bandah Formation, Jaisalmer Basin, Rajasthan, Western India

ABSTRACT A small vertebrate faunal assemblage of late Middle Eocene (Bartonian) age is described from the Bandah Formation, a shallow marine deposit in the Jaisalmer Basin of Rajasthan state, Western

An Overview of Recent Advances in the Mesozoic–Palaeogene Vertebrate Paleontology in the Context of India’s Northward Drift and Collision with Asia

TLDR
This review article summarizes the recent work done in India on fossil vertebrates from the Mesozoic-early Paleogene interval, with focus on the past five years, and suggests that the Indian landmass was the centre of origin/early evolution for several orders of modern mammals, including cetaceans, perissodactyls and primates.

Transition of Eocene Whales from Land to Sea: Evidence from Bone Microstructure

TLDR
This study highlights the strong need for homologous sections in comparative microanatomical studies, and the importance of combining information from several bones of the same taxon for improved functional interpretation.

India’s geodynamic evolution during the Eocene: perspectives on the origin and early evolution of modern mammal orders

In recent years, explosion of research in the early Tertiary mammals of India has attracted widespread interest because of the importance of this fauna in understanding biogeographic origins, early

Constraints on the timescale of animal evolutionary history

TLDR
Calibrations for 88 key nodes across the phylogeny of animals, ranging from the root of Metazoa to the last common ancestor of Homo sapiens, are presented, highlighting the importance of identifying crown (not stem) fossils, levels of confidence in their attribution to the crown, current chronostratigraphic precision, the primacy of the host geological formation and asymmetric confidence intervals.

An Eocene Greenhouse Forested India: Were Biotic Radiations Triggered by Early Palaeogene Thermal Events?

  • A. SahniR. Patnaik
  • Environmental Science, Geography
    Journal of the Geological Society of India
  • 2022
During the last two decades, work carried out in the Eocene lignite sequences of Rajasthan and Gujarat has thrown considerable light on the terrestrial biotas during the drift of India and radically

Tracing whale myoglobin evolution by resurrecting ancient proteins

TLDR
The experimental and theoretical analyses demonstrated that whale Mb adopted two distinguished strategies to increase the protein concentration in vivo along the evolutionary history of deep sea adaptation; gaining precipitant tolerance in the early phase of the evolution, and increase of folding stability in the late phase.

References

SHOWING 1-10 OF 97 REFERENCES

Whales originated from aquatic artiodactyls in the Eocene epoch of India

TLDR
It is shown that the Eocene south Asian raoellid artiodactyls are the sister group to whales and that Raoellids were aquatic waders, which indicates that aquatic life in this lineage occurred before the origin of the order Cetacea.

Eocene evolution of whale hearing

TLDR
The origin of whales (order Cetacea) is one of the best-documented examples of macroevolutionary change in vertebrates, and the fossil record indicates that this evolutionary transition took less than 15 million years.

The Early Radiations of Cetacea (Mammalia): Evolutionary Pattern and Developmental Correlations

TLDR
The origin and early evolution of Cetacea (whales, dolphins, and porpoises) is one of the best examples of macroevolution as documented by fossils, and a study of patterns of correlations among morphological traits to test hypotheses of developmental links among organ systems is suggested.

From Land to Water: the Origin of Whales, Dolphins, and Porpoises

TLDR
This work focuses on the evolution of cetacean organ systems, as these document the transition from land to water in detail.

Synopsis of the Earliest Cetaceans

The story of cetacean origin, early evolution, diversification, and dispersal has dramatically changed in the last 20 years, related in large part to discoveries made in Pakistan, India, and the

Locomotor evolution in the earliest cetaceans: functional model, modern analogues, and paleontological evidence

TLDR
It is concluded that Ambulocetus may have locomoted by a combination of pelvic paddling and dorsoventral undulations of the tail, and that its locomotor mode in water resembled that of the modern otter Lutra most closely.

New whale from the Eocene of Pakistan and the origin of cetacean swimming

TLDR
This is the oldest fossil whale described from deep-neritic shelf deposits, and it shows that tail swimming evolved early in the history of cetaceans.

A new, diminutive Eocene whale from Kachchh (Gujarat, India) and its implications for locomotor evolution of cetaceans

TLDR
Vertebral proportions indicate that the vertebral column of the new cetACEan functioned in different ways from any other known Eocene or Recent cetacean, and suggests that the mobility of the back may have approximated that of otters.

Land-to-sea transition in early whales: evolution of Eocene Archaeoceti (Cetacea) in relation to skeletal proportions and locomotion of living semiaquatic mammals

TLDR
It appears that the land-to-sea transition in whale evolution involved at least two distinct phases of locomotor specialization: hindlimb domination for drag-based pelvic paddling in protocetids (Rodhocetus), with tail elongation for stability, followed by lumbus domination for lift-based caudal undulation and oscillation in basilosaurids (Dorudon).

Hippopotamus and whale phylogeny

TLDR
It is demonstrated that Hippopotamidae is the closest extant family to Cetacea and that raoellids are the closest extinct group, consistent with previous phylogenetic studies, and supports the view that the aquatic adaptations in hippopotamids and cetaceans are inherited from their common ancestor.
...