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About 50 million years ago
- Cetaceans (whales, dolphins, and porpoises) are an order of mammals that originated about 50 million years ago in the Eocene epoch.
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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.
- Mark D. Uhen
- 2007
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC. ABSTRACT. 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.
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.
- Mark D. Uhen
- muhen@gmu.edu
- 2013
Harbor seal, walrus, dugong, and right whale) The first mammals were certainly terrestrial. There is good evidence that mammals evolved from reptile-like ancestor. Therefore at some point there was a transition from terrestrial environment to an aquatic lifestyle in this group of species. How did that occur?
- 1MB
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Jan 26, 2015 · Marine mammal genomes showed a large number of parallel substitutions (blue) that occurred along the branches of at least two marine mammal lineages since they evolved from a terrestrial...
- Andrew D Foote, Andrew D Foote, Yue Liu, Gregg W C Thomas, Tomáš Vinař, Jessica Alföldi, Jixin Deng,...
- 2015
Jan 27, 2015 · When marine mammals such as whales, dolphins, manatees and walruses moved from land to water, a series of physical abilities —– limbs adapted for swimming, less dense bones that make them more...
Nov 15, 2019 · Early Cetacea are classified as Archaeoceti (six families), and their fossils reveal the morphological and functional evolution of early, terrestrial Artiodactyla to fully aquatic Cetacea over 15 million years during the Eocene (~52 Mya). The evolution of modern Cetacea (Neoceti: Mysticeti and Odontoceti) began in the late Eocene (~37 Mya).
