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May 21, 2007 · The fossil record demonstrates that mammals re-entered the marine realm on at least seven separate occasions. Five of these clades are still extant, whereas two are extinct. This review presents a brief introduction to the phylogeny of each group of marine mammals, based on the latest studies using both morphological and molecular data. Evolutionary highlights are presented, focusing on ...
- Mark D. Uhen
- 144
- 2007
- 21 May 2007
Apr 16, 2009 · 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. The transition from land to water is documented by a series of intermediate fossils, many of ...
- J. G. M. Thewissen, Lisa Noelle Cooper, Lisa Noelle Cooper, John C. George, Sunil Bajpai
- 2009
People also ask
Did marine mammals evolve back to the sea after 300 million years?
When did mammalian evolution start?
Do marine mammals have evolutionary histories?
What animals ruled the ocean before large mammals?
The mammals, once small and rodent-like, took advantage of the dinosaurs’ extinction and evolved in new directions, with some lineages eventually giving rise to the whales, seals, and manatees that live in the ocean today.
Oct 18, 2012 · Annalisa Berta leads readers through a vast range of topics regarding the evolution of marine mammals in Return to the Sea: The Life and Evolutionary Times of Marine Mammals. In this volume geared towards non-specialists (one might even suggest non-scientists), topics ranging from systematics, speciation, diversification, paleoclimate, paleoecology, ecology, and conservation of Cetacea ...
- Mark D. Uhen
- muhen@gmu.edu
- 2013
- 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
Feb 20, 2015 · Reptiles continued to dominate the top end of the size spectrum during the Mesozoic. Cetaceans were the first mammals to evolve a marine lifestyle and have occupied the largest marine body sizes since they first invaded the oceans during the Eocene (48 Ma) ( Fig. 3 ).
Jun 22, 2016 · Though mammals adapted on land, a new study has shown that during three major independent evolutionary events, a number of mammals hearkened back to the sea.
