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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.
Archaeoceti ("ancient whales"), or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene (50 to 23 million years ago). [1] Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of ...
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. Cetaceans are fully aquatic mammals belonging to the order Artiodactyla and branched off from other artiodactyls around 50 mya.
Mediterranean cetaceans. Minoan depiction of a common dolphin in the "Dolphin Fresco " in the Palace of Knossos (Crete), circa 2,000 BC. Mediterranean cetaceans constitute a unique assemblage of species found in the virtually closed basin of the Mediterranean Sea. This assemblage differs from those found in the North Atlantic or the Red Sea.
The Dark Ages is a term for the Early Middle Ages (c. 5th –10th centuries), or occasionally the entire Middle Ages (c. 5th –15th centuries), in Western Europe after the fall of the Western Roman Empire, which characterises it as marked by economic, intellectual, and cultural decline. The concept of a "Dark Age" as a historiographical ...
Portal. : Cetaceans/Intro. Cetacea (/ sɪˈteɪʃə /; from Latin cetus ' whale ', from Ancient Greek κῆτος (kêtos) ' huge fish, sea monster ') is an infraorder of aquatic mammals belonging to the suborder Whippomorpha that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body ...
Whippomorpha or Cetancodonta is a group of artiodactyls that contains all living cetaceans (whales, dolphins, and porpoises) and the hippopotamids. [1] All whippomorphs are descendants of the last common ancestor of Hippopotamus amphibius and Tursiops truncatus. This makes it a crown group. [2] Whippomorpha is a suborder within the order ...
It is unclear at present whether protocetids had flukes (the horizontal tail fin of modern cetaceans). However, what is clear is that they are adapted even further to an aquatic life-style. In Rodhocetus , for example, the sacrum – a bone that in land-mammals is a fusion of five vertebrae that connects the pelvis with the rest of the ...