Crassigirinus ( lat. Crassigyrinus scoticus ) - a primitive four-legged (" amphibian ") beginning of the Carboniferous era .
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| Crassigyrinus |
The systematic position of Crassigirinus is unclear, it does not apply to dark spondylae, it may refer to Anthracosaurs , but it has features of both.
Crassigirinus has a high skull with a short muzzle. The orbits are quadrangular, extended upward, directed to the side. The surface of the bones of the skull is abundantly sculpted (it has been suggested that the skull could be covered with skin outgrowths for masking). There is a movable joint between the cheeks and the roof of the skull (as in anthracosaurs). There is an โear notchโ that holds the splatter. The palate is primitive, like ripidistii. Very powerful teeth on the palate.
On the front surface of the skull, between the premaxillary bones, there is a pear-shaped hole connected with the anterior palatine window. At one time, it was assumed that below the nostrils there was an opening for a sensitive tentacle (like worms ), but now it is proved that this is a mistake. On the lower jaw there are large openings into which, with a closed mouth, the ends of the palate fangs entered.
The skeleton is weak, the body is long, the forelimbs are extremely small (the length of the shoulder is less than the diameter of the orbit), the hind limbs are longer than the forelimbs. The number of fingers is not known exactly. The length reached 1.5-2 meters. Undoubtedly, crassigirinus was a predator, one of the most powerful predators of its era. He lived in swamps and overgrown shallow reservoirs, waiting for prey in troubled waters. Despite its primitiveness, it is a secondary water animal.
Crassigirinus was described by fragments of the jaws of D. Watson in 1929 , and its first remains were discovered back in the 19th century. All remnants come from the Early Carboniferous (Visean) of Scotland. A modern description is made in the 1980-1990s. Now he has become quite popular - for example, in the series " Prehistoric Park " Nigel Marven catches crassigirinus with his bare hands.
Literature
- Ahlberg, PE and Milner, AR 1994. The origin and early diversification of tetrapods. Nature 368: 507-514.
- Andrews, SM, Browne, MAE, Panchen, AL &. and Wood, SP 1977. Discovery of amphibians in the Namurian (Upper Carboniferous) from Fife. Nature 265: 529-532.
- Carroll, RL 1995. Problems of the phylogenetic analysis of Paleozoic choanates. Bull Mus Natl Hist Nat Paris 17.389-445.
- Clack, JA 1996. The palate of Crassigyrinus scoticus, a primitive tetrapod from the Lower Carboniferous of Scotland. In: Milner, AR (Ed.) Special Papers in Palaeontology 52, pp. 55-64.
- Gauthier, J., Canatella, D., De Queiroz, K., Kluge, A. and Rowe, T. 1989. Tetrapod phylogeny. In: Fernholm, B., Bremer, K. and Jornwall, H., The Hierarchy of Life. London, Elsevier Science Publishers, pp. 337-353.
- Laurin, M. & Reisz, RR 1997. A new perspective on tetrapod phylogeny. In Sumida, SS and Martin, KLM (Eds) Amniote Origins - completing the transition to land, pp. 9-59. London: Academic Press.
- Panchen, AL 1973. On Crassigyrinus scoticus Watson, a primitive amphibian from the Lower Carboniferous of Scotland. Palaeontology 16: 179-193.
- Panchen, AL 1985. On the amphibian Crassigyrinus scoticus Watson from the Carboniferous of Scotland. Philosophical Transactions of the Royal Society of London. Series B 309: 461-568.
- Panchen, AL and Smithson, TR 1990. The pelvic girdle and hind limb of Crassigyrinus scoticus (Lydekker) from the Scottish Carboniferous and the origin of the tetrapod pelvic skeleton. Transactions of the Royal Society of Edinburgh: Earth Sciences. 81: 31-44.
Links
- https://web.archive.org/web/20070227221442/http://ag.arizona.edu/tree/eukaryotes/animals/chordata/crassigyrinus/crassigyrinus.html
- https://web.archive.org/web/20080516051658/http://scienceblogs.com/tetrapodzoology/2007/07/crassigyrinus_or_how_id_love_a.php
- https://web.archive.org/web/20080515074807/http://www.palaeos.com/Vertebrates/Units/150Tetrapoda/150.400.html#Crassigyrinidae