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尾羽龙(Caudipteryx)的新材料及其重要骨骼特征的补充和修订

2000年 第38卷 第4期:241~254

发表日期:2009-01-21李志恒来源:放大 缩小

编辑:周忠和 汪筱林 张福成 徐星

摘要:Two nearly complete specimens of Caudipteryx preserved a lot more new information about its skeletal anatomy. It has some unexpected bird characters such as the manual digital format of “2-3-2” as in advanced birds rather than the previously recognized “2-3-4” as in Archaeopteryx, Confuciusornis and most theropods, the ungula of the third manual digit is lost; in the skull the nasal opening is larger than the antorbital fenestra, the tail is composed of 22 unfused caudals, there exist only 9 dorsal vertebrae, there are about 12 cervical vertebrae. On the other hand, both new specimens corfirm that the pubis of Caudipteryx is antero-ventrally rather than posteriorly oriented; the fibula contacts the calcaneum; the quadratojugal contacts both the squamosal and the quadrate. The teeth of Caudipteryx are restricted to the premaxilla in all known specimens. The scapula is expanded at the distal end. The coracoid has a prominent biceps tubercle and possesses an elliptic supracoracoid foramen. Both new specimens appear to confirm that the first metatarsal articulates with the postern-medial surface of the second metatarsal and the hallux of the foot is at least partially reversed, therefore suggesting that the ancestor of Caudipteryx had probably possessed the arboreal capability. The reduction of the third manual digit in Caudipteryx also provides further evidence for the homology of the three manual digits in birds and theropod dinosaurs although the reduction of the third digit had obviously appeared many times in the history of dinosaurs and birds. Although Caudipteryx is still accepted as a feathered dinosaur, its newly discovered remarkable bird-like characters probably indicate that its phylogenetic position remains a debatable issue.

关键词:辽宁北票,早白垩世,尾羽龙,骨骼特征

卷期:38卷 04期

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