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Apr 16, 2009 · Mammals. Cetaceans (whales, dolphins, and porpoises) are an order of mammals that originated about 50 million years ago in the Eocene epoch. Even though all modern cetaceans are obligate aquatic mammals, early cetaceans were amphibious, and their ancestors were terrestrial artiodactyls, similar to small deer.
- J. G. M. Thewissen, Lisa Noelle Cooper, Lisa Noelle Cooper, John C. George, Sunil Bajpai
- 2009
May 21, 2007 · Evolution of marine mammals: Back to the sea after 300 million years. Mark D. Uhen. First published: 21 May 2007. https://doi.org/10.1002/ar.20545. Citations: 144. Sections. PDF. Tools. Share. Abstract. The fossil record demonstrates that mammals re-entered the marine realm on at least seven separate occasions.
- Mark D. Uhen
- 2007
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- 1 Archaeoceti
- 2 Mysticeti
- 3 Odontoceti
The story of Cetacea began with the evolutionary radiation of placental mammals after the extinction of the dinosaurs and most large marine reptiles at the end of the Cretaceous about 66 million years ago (hereafter written Mya) (Fig. 2.1). The Paleocene (66–56 Mya) was the first epoch of the Cenozoic, a time when many placental mammals were small ...
Late Eocene Dorudontidae, the likely predecessors of early Mysticeti, had teeth to capture large or intermediate size prey, while modern Mysticeti use baleen to filter large numbers of small prey (see Sect. 8.1.1.1). Hence, there must have been a transitional phase from toothed Dorudontidae that used raptorial biting and intraoral suction to modern...
As with Mysticeti, late Eocene Dorudontidae were likely predecessors of early Odontoceti. However, they retained, to varying degrees, their adult dentition, although not necessarily for feeding. Some species continued to use teeth to capture small and intermediate-sized prey, but others evolved suction feeding and lost the functional use of teeth (...
- Randall W. Davis
- 2019
The Killer appetites: An evolutionary tale of seafood predation and digestion by marine mammalsTerrie Williams, Professor of Ecology & Evolutionary Biology, UC Santa Cruz, and Director of the Marine Mammal Physiology Project, Long Marine Lab It has taken 50 million years for cetaceans and pinnipeds to evolve into the largest, most efficient pred...
Apr 16, 2015 · April 16, 2015. The oceans are teeming with tetrapods—“four-legged” birds, reptiles, mammals and amphibians—that have repeatedly transitioned from the land to the sea, adapting their legs...
Oct 18, 2012 · I particularly appreciated the paleoecology section, as it showed how the evolution of marine mammals was deeply intertwined with the past positions of the continents, evolution of Earth’s oceans, and with other oceanographic factors like temperature, salinity, and productivity.
The hunt for the ancestors of living birds began with a specimen of Archaeopteryx, the first known bird, discovered in the early 1860s. Like birds, it had feathers along its arms and tail, but unlike living birds, it also had teeth and a long bony tail.
