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There is no general agreement on where the Quaternary extinction event ends, and the Holocene, or anthropogenic, extinction begins, or if they should be considered separate events at all. [ 244 ] [ 245 ] Some authors have argued that the activities of earlier archaic humans have also resulted in extinctions, though the evidence for this is ...
The order Artiodactyla consists of 349 extant species belonging to 132 genera. This does not include hybrid species or extinct prehistoric species. Modern molecular studies indicate that the 132 genera can be grouped into 23 families; these families are grouped into named suborders and many are further grouped into named clades, and some of these families are subdivided into named subfamilies.
A more recent theory combining both Deccan volcanism and the impact hypothesis has been developed by teams at UC Berkeley led by Paul Renne and Mark Richards. This theory proposes that the impact itself instigated the most intense period of Deccan eruptions, both of which had devastating effects contributing to the K-Pg extinction.
The 20th century saw a major renewal of interest in mass extinction events and their effect on the course of the history of life. This was particularly true after 1980 when Luis and Walter Alvarez put forward the Alvarez hypothesis claiming that an impact event caused the Cretaceous–Paleogene extinction event , which killed off the non-avian ...
The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates (Artiodactyla) 50 million years ago (mya) and to have proceeded over a period of at least 15 million years. [2] Cetaceans are fully aquatic mammals belonging to the order Artiodactyla and branched off from other artiodactyls around 50 mya.
Andrewsarchus (/ ˌ æ n d r uː ˈ s ɑːr k ə s /), meaning "Andrews' ruler", is an extinct genus of artiodactyl that lived during the Middle Eocene in what is now China. The genus was first described by Henry Fairfield Osborn in 1924 with the type species A. mongoliensis based on a largely complete cranium.
Order Artiodactyla (even-toed ungulates) Suborder Tylopoda (camelids) Artiofabula [1] (ruminants, pigs, peccaries, whales, and dolphins) Suborder Suina (pigs and peccaries) Family Suidae 19 species (pigs) Family Tayassuidae 4 species (peccaries) Cetruminantia [1] (ruminants, whales, and dolphins)
Artiocetus fossils represent intermediate forms between land-living ungulates and whales, lending support to the theory that whales and hippopotami descended from a common ancestor. The discovery of this fossil is important as it helped solidify the theory that whales shared a common ancestor with Artiodactyla.