The dominant group of Birds during much of the Cretaceous Period were the Enatiornithine, toothed Birds related, but not ancestral, to modern Birds. The largest known species of Enatiornithine from the Early Cretaceous is Pengornis houi, described from a single specimen from the Jiufotang Formation of northern China, part of the Jehol Biota.
In a paper published in the journal Vertebrata PalAsiatica on 21 January 2014, Hu Han of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the University of the Chinese Academy of Sciences and Zhou Zhong-He and Jingmai O'Conner, also of the Key Laboratory of Vertebrate Evolution and Human Origins, describe a second specimen of Pengornis from the Early Cretaceous Jiufotang Formation of western Liaoning Province.
The new specimen is an almost complete articulated skeleton with some feathers intact. It shows strong similarities to Pengornis houi, but is also different enough that were it a second adult specimen, then it would probably be placed within a separate species within the same genus. However, since it is not a completely mature specimen it cannot be confidently asserted that it is a new species either. For this reason it is placed in the genus Pengornis, but not assigned to species level.
Photo of the subadult specimen of Pengornis sp. Hu et al. (2014).
Camera lucida drawing of the subadult specimen of Pengornis sp.
Abbreviations: as. astragalus; ca. calcaneum; ce. cervical vertebrae; co. coracoid; cv.
caudal vertebrae; dr. dorsal rib; fe. femur; fi. fibula; ft. feathers; fu. furcula;
ga. gastralia; hu. humerus; il. ilium; is. ischium; mcI-III. metacarpals I-III
; md. manual digits; mtI-V. metatarsals I-V; pd. pedal digits; pu. pubis;
py. pygostyle; r. radius; ra. radiale; sc. scapula; se. semilunate carpal
; sk. skull; sr. sternal rib; st. sternum; sy. synsacrum; ti. tibia; tv. thoracic
vertebrae; u. ulna; ul. ulnare; up. uncinate process.Hu et al. (2014).
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