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The earliest known ancestor of arctic whales is Denebola brachycephala from the late Miocene around 9–10 million years ago. [55] A single fossil from Baja California indicates the family once inhabited warmer waters. [27] [56] [57] Acrophyseter skull. Ancient sperm whales differ from modern sperm whales in tooth count and the shape of the ...
The first branch contained ancestors of Cetacea; semi-aquatic protowhales such as Pakicetus in the group Archaeoceti, which developed into the exclusively aquatic ancestors of modern cetaceans. [28] One evolutionarily significant whale ancestor was the raoellid Indohyus, which was a Himalayas-dwelling, digitgrade omnivore roughly the size of a ...
An evolutionary tree (of Amniota, for example, the last common ancestor of mammals and reptiles, and all its descendants) illustrates the initial conditions causing evolutionary patterns of similarity (e.g., all Amniotes produce an egg that possesses the amnios) and the patterns of divergence amongst lineages (e.g., mammals and reptiles ...
The discovery of this fossil is important as it helped solidify the theory that whales shared a common ancestor with Artiodactyla. In 2005, an international team of scientists suggested that whales and hippopotami share a common water and terrestrial dwelling ancestor, which lived 50 to 60 million years ago.
The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families : Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey ...
A most recent common ancestor (MRCA), also known as a last common ancestor (LCA), is the most recent individual from which all organisms of a set are descended. The term is also used in reference to the ancestry of groups of genes ( haplotypes ) rather than organisms.
The large teeth of the raptorial sperm whales either evolved once in the group with a basilosaurid-like common ancestor, or independently in Livyatan. The large temporal fossa in the skull of raptorial sperm whales is thought to a plesiomorphic feature, that is, a trait inherited from a common ancestor.
They are closely related to the hippopotamus, sharing a common ancestor that lived around 54 million years ago (mya). [6] The primitive cetaceans, or archaeocetes, first took to the sea approximately 49 mya and became fully aquatic by 5–10 million years later. [7] The ancestors of toothed whales and baleen whales diverged in the early Oligocene.