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出典:『Wikipedia』 (2011/07/13 18:41 UTC 版)

英語による解説

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Probelesodon is an extinct genus of chiniquodontid cynodont. Fossils have been found from Argentina and Brazil of Triassic age. Specimens were first discovered from the Chañares Formation in La Rioja Provence, Argentina that date back to the Anisian stage of the early Middle Triassic. A new species, P. sanjuanensis, was named in 1996 on the basis of a skull found from the Ischigualasto Formation. This extends the temporal range of Probelesodon into the Carnian stage of the Late Triassic. The occurrence of the genus in these strata suggests that it also existed during the deposition of the Los Rastros Formation, which also outcrops in the same area as the localities where fossils have been found, although specimens have yet to be found from this formation. The presence of the genus in the Ischigualasto Formation is restricted to the earlier strata, becoming completely extinct soon after along with the last of the carnivorous cynodonts in the area. This has been taken as evidence for the gradual replacement of therapsid fauna with the later mainly archosaur-dominated faunas of the Late Triassic. Evidence from the Chañares Formation also seems to support this faunal transition.