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Ankylosaurs and glyptodont mammals both had spiked tails. [73] The sauropods and giraffes independently evolved long necks. [74] The horned snouts of ceratopsian dinosaurs like Triceratops have also evolved several times in Cenozoic mammals: rhinos, brontotheres, Arsinoitherium, and Uintatherium. [75] Rhynchosaur teeth resemble that of the ...
Multituberculate mammals (genus Rugosodon) appear in eastern China. 155 Ma First blood-sucking insects (ceratopogonids), rudist bivalves, and cheilostome bryozoans. Archaeopteryx, a possible ancestor to the birds, appears in the fossil record, along with triconodontid and symmetrodont mammals. Diversity in stegosaurian and theropod dinosaurs.
Pelycosaur (/ ˈ p ɛ l ɪ k ə ˌ s ɔːr / PEL-ih-kə-sor) [1] is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term mammal-like reptile had been used, [2] and pelycosaur was considered an order, but this is now thought to be incorrect and outdated.
The tetrapods, including all large- and medium-sized land animals, have been among the best understood animals since earliest times. By Aristotle's time, the basic division between mammals, birds and egg-laying tetrapods (the "herptiles") was well known, and the inclusion of the legless snakes into this group was likewise recognized. [28]
Hox genes play a massive role in some amphibians and reptiles in their ability to regenerate lost limbs, especially HoxA and HoxD genes. [1]If the processes involved in forming new tissue can be reverse-engineered into humans, it may be possible to heal injuries of the spinal cord or brain, repair damaged organs and reduce scarring and fibrosis after surgery.
Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny [ 1 ] (the evolution of species). The science began in the classical era , continuing in the early modern period with work by Pierre Belon who noted the similarities of the skeletons ...
[12] [13] The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis by Carl Woese resulted in the three-domain system , arguing for two major splits in the early evolution of life.
A = Anapsid, B = Synapsid, C = Diapsid. It was traditionally assumed that first reptiles were anapsids, having a solid skull with holes only for the nose, eyes, spinal cord, etc.; [10] the discoveries of synapsid-like openings in the skull roof of the skulls of several members of Parareptilia, including lanthanosuchoids, millerettids, bolosaurids, some nycteroleterids, some procolophonoids and ...