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标题：The illusory evidence for Asian Brachiosauridae : new material of Erketu ellisoni and a phylogenetic reappraisal of basal Titanosauriformes. (American Museum novitates, no. 3700)
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作者：Ksepka, Daniel T. ; Norell, Mark.
期刊名称：American Museum Novitates
印刷版ISSN：0003-0082
电子版ISSN：1937-352X
出版年度：2010
卷号：2010
语种：
出版社：American Museum of Natural History
摘要：Phylogenetic relationships among the diverse Cretaceous sauropods of East Asia have long been controversial. Debate has centered on whether there is any evidence for an endemic clade of Asian species ("Euhelopodidae") and on the placement of these taxa within the context of higher sauropod phylogeny. While most Cretaceous sauropod taxa from Asia are recognized as part of Somphospondyli, recent discoveries have suggested Brachiosauridae may have dispersed into Asia as well. We present new fossils and analyses bearing on these issues. Additional material of the holotype individual of Erketu ellisoni recovered on a subsequent visit to the type locality expands the character data available for this unique sauropod. Associated sauropod dorsal and caudal vertebrae were collected from the same horizon, at a location approximately 2 km from the holotype excavation. The dorsal vertebra exhibits synapomorphies suggesting a representative of Titanosauria co-occurred with Erketu ellisoni. These new specimens, as well as recent discoveries of contemporary Asian sauropod taxa, allow a basis for phylogenetic reappraisal of Erketu and related taxa. Phylogenetic results support a sister group relationship between the Asian Cretaceous sauropods Erketu and Qiaowanlong. Although Qiaowanlong was described as a brachiosaurid, it joins Erketu on the somphospondylian side of the Brachiosauridae-Somphospondyli divergence, erasing the evidence for the dispersal of Brachiosauridae into Asia.
关键词：Erketu ellisoni.; Dinosaurs.; Mongolia.; Dornogovʹ Aĭmag (Mongolia)