[D] Sapeornis chaoyangensis [~/~]
Describer
Zhou & Zhang, 2002
Time
Cretaceous Early
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Incertae Sedis
Diet
Jiufotang Formation, Liaoning, Shangheshou, Chaoyang City, China
Info
Nearly complete skeleton without skull.
Zhou, Z. & Zhang, F. (2002). Largest bird from the Early Cretaceous and its implications for the earliest avian ecological diversification. Naturwissenschaften 89:34–38.
Type specimen
Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Beijing, China collection number V 12698
Etymology
SAPE is the abbreviation for the Society of Avian Paleontology and Evolution. The fifth SAPE conference was held in China in June 2000, shortly before the holotype was collected. The species name is derived from the type locality ?Chaoyang?.
Diagnosis
Sapeornis possesses more derived features than Archaeopteryx, such as a fused pygostyle. It is different from Confuciusornis in having, among many features, a welldeveloped fibula and a significantly different proximal end of the humerus. It differs from all the other avian taxa described from the early Cretaceous of China in retaining many primitive traits including the fifth metatarsal, the long first manual digit and short coracoid. It is also distinguishable from other early Cretaceous birds by possessing a large body size and extremely elongated forelimbs [ratio of forelimb (humerus + ulna + carpometacarpus) to hindlimb (femur + tibiotarsus + tarsometatarsus) is 1.55], the deltoid crest of the humerus measures about one-third of the length of the humerus, the dorso-distal portion of the deltoid crest tapers into an acute process, the tibiotarsus is shorter than the pubis, and the femur nearly as long as the tibiotarsus.
Concerning its phylogenetic position, Sapeornis is found to be the most primitive bird except for Archaeopteryx. It shares several primitive features with Archaeopteryx and dromaeosaurs, such as a short and nonstrut-like coracoid, well developed manual digit I, a fibula reaching the distal end of the tarsal joint, the presence of a free tarsal, and the presence of a fifth metatarsal. On the other hand, Sapeornis exhibits more derived characters than Archaeopteryx, such as the presence of heterocoelous cervicals, the presence of a pygostyle, a fused carpometacarpus, pubic symphysis about one third the length of the pubis, and the fact that the ulna is longer than the humerus.
Zhou, Z and Zhang, F. (2003) Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of Liaoning, China Can. J. Earth Sci./Rev. can. sci. Terre 40(5): 731-747
Abstract
Two new, nearly completely articulated skeletons of Sapeornis chaoyangensis provide much new information about the anatomy of this basal avian, particularly in the skull, pectoral girdle, forelimb, and hind limb. This new material shows that the hand of Sapeornis, with a phalangeal formula of \\\"2–3–2,\\\" was more derived than previously reconstructed. The skeleton of Sapeornis has several unique features, such as a distinctively elongated fenestra on the proximal end of the humerus, a robust furcula with a distinctive hypocleidum, and an elongated forelimb.
Sapeornis exhibits a combination of derived and primitive features, including a short, robust non-strut-like coracoid and a fibula reaching the distal end of the tarsal joint (as in Archaeopteryx), a pygostyle, reduced manual digits, and a well-fused carpometacarpus (as in more advanced birds). These features further indicate the mosaic pattern in the early evolution of birds and confirm the basal position of Sapeornis near Archaeopteryx and Jeholornis in the phylogeny of early birds. The preservation of gastroliths in one of the new specimens also represents the first Chinese Mesozoic bird with such evidence, indicating a herbivorous feeding habit and providing further evidence for our understanding of the diet diversification in early avian evolution.
Zhou & Zhang, 2002
Time
Cretaceous Early
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Incertae Sedis
Diet
Jiufotang Formation, Liaoning, Shangheshou, Chaoyang City, China
Info
Nearly complete skeleton without skull.
Zhou, Z. & Zhang, F. (2002). Largest bird from the Early Cretaceous and its implications for the earliest avian ecological diversification. Naturwissenschaften 89:34–38.
Type specimen
Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Beijing, China collection number V 12698
Etymology
SAPE is the abbreviation for the Society of Avian Paleontology and Evolution. The fifth SAPE conference was held in China in June 2000, shortly before the holotype was collected. The species name is derived from the type locality ?Chaoyang?.
Diagnosis
Sapeornis possesses more derived features than Archaeopteryx, such as a fused pygostyle. It is different from Confuciusornis in having, among many features, a welldeveloped fibula and a significantly different proximal end of the humerus. It differs from all the other avian taxa described from the early Cretaceous of China in retaining many primitive traits including the fifth metatarsal, the long first manual digit and short coracoid. It is also distinguishable from other early Cretaceous birds by possessing a large body size and extremely elongated forelimbs [ratio of forelimb (humerus + ulna + carpometacarpus) to hindlimb (femur + tibiotarsus + tarsometatarsus) is 1.55], the deltoid crest of the humerus measures about one-third of the length of the humerus, the dorso-distal portion of the deltoid crest tapers into an acute process, the tibiotarsus is shorter than the pubis, and the femur nearly as long as the tibiotarsus.
Concerning its phylogenetic position, Sapeornis is found to be the most primitive bird except for Archaeopteryx. It shares several primitive features with Archaeopteryx and dromaeosaurs, such as a short and nonstrut-like coracoid, well developed manual digit I, a fibula reaching the distal end of the tarsal joint, the presence of a free tarsal, and the presence of a fifth metatarsal. On the other hand, Sapeornis exhibits more derived characters than Archaeopteryx, such as the presence of heterocoelous cervicals, the presence of a pygostyle, a fused carpometacarpus, pubic symphysis about one third the length of the pubis, and the fact that the ulna is longer than the humerus.
Zhou, Z and Zhang, F. (2003) Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of Liaoning, China Can. J. Earth Sci./Rev. can. sci. Terre 40(5): 731-747
Abstract
Two new, nearly completely articulated skeletons of Sapeornis chaoyangensis provide much new information about the anatomy of this basal avian, particularly in the skull, pectoral girdle, forelimb, and hind limb. This new material shows that the hand of Sapeornis, with a phalangeal formula of \\\"2–3–2,\\\" was more derived than previously reconstructed. The skeleton of Sapeornis has several unique features, such as a distinctively elongated fenestra on the proximal end of the humerus, a robust furcula with a distinctive hypocleidum, and an elongated forelimb.
Sapeornis exhibits a combination of derived and primitive features, including a short, robust non-strut-like coracoid and a fibula reaching the distal end of the tarsal joint (as in Archaeopteryx), a pygostyle, reduced manual digits, and a well-fused carpometacarpus (as in more advanced birds). These features further indicate the mosaic pattern in the early evolution of birds and confirm the basal position of Sapeornis near Archaeopteryx and Jeholornis in the phylogeny of early birds. The preservation of gastroliths in one of the new specimens also represents the first Chinese Mesozoic bird with such evidence, indicating a herbivorous feeding habit and providing further evidence for our understanding of the diet diversification in early avian evolution.