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 ...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 ungual 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 confirm that the pubis of Caudipteryx is anteroentrally 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 postero edial 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 birdike characters probably indicate that its phylogenetic position remains a debatable issue.展开更多
本文记述了辽宁北票义县组一件新的初鸟类(Avialae)化石,这是继中华神州鸟(Shenzhouraptor sinensis Ji et al,2002)之后初鸟类化石的又一发现.它以上下颌无齿而具角质喙、胸骨发达且具龙骨突、前肢显著长于后肢等特征与始祖鸟(Archaeop...本文记述了辽宁北票义县组一件新的初鸟类(Avialae)化石,这是继中华神州鸟(Shenzhouraptor sinensis Ji et al,2002)之后初鸟类化石的又一发现.它以上下颌无齿而具角质喙、胸骨发达且具龙骨突、前肢显著长于后肢等特征与始祖鸟(Archaeopteryx)不同,以后肢第Ⅰ趾爪已反转而与其它3趾对握等特征与神州鸟相区别,该化石被命名为东方吉祥鸟(新属、新种)(Jixiangornis orientalisgen.et sp.nov.)中国辽西新近发现的中华神州鸟和东方吉祥鸟(新属、新种)目前是世界上最古老最原始真正具有角质喙和飞行能力的原始鸟类.展开更多
文摘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 ungual 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 confirm that the pubis of Caudipteryx is anteroentrally 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 postero edial 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 birdike characters probably indicate that its phylogenetic position remains a debatable issue.
基金funded by China Geological Survey and by Department of International CooperationScience and Technology under the Ministry of Land and Resources,China
文摘本文记述了辽宁北票义县组一件新的初鸟类(Avialae)化石,这是继中华神州鸟(Shenzhouraptor sinensis Ji et al,2002)之后初鸟类化石的又一发现.它以上下颌无齿而具角质喙、胸骨发达且具龙骨突、前肢显著长于后肢等特征与始祖鸟(Archaeopteryx)不同,以后肢第Ⅰ趾爪已反转而与其它3趾对握等特征与神州鸟相区别,该化石被命名为东方吉祥鸟(新属、新种)(Jixiangornis orientalisgen.et sp.nov.)中国辽西新近发现的中华神州鸟和东方吉祥鸟(新属、新种)目前是世界上最古老最原始真正具有角质喙和飞行能力的原始鸟类.
