Monday, February 17, 2014

[Paleontology • 2014] Reinterpretation of the Early Cretaceous maniraptoran Zhongornis haoae (Dinosauria: Theropoda) as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs



Fig. 1 Photograph of the holotype of Zhongornis haoae DNHM D2456
Scale bar equals 2 cm

Abstract 
The recently described maniraptoran theropod Zhongornis haoae, known from a single juvenile specimen, was originally identified as a bird. However, morphological re-evaluation reveals striking resemblances to both Oviraptorosauria and Scansoriopterygidae. The reduced, but still long, boney tail is reinterpreted as having approximately twenty vertebrae and is reminiscent of the tails of Caudipteryx and Epidexipteryx in its proportions and morphology. Other morphological similarities with basal oviraptorosaurs include a short and deep skull, and a reduced minor digit. Zhongornis also differs strikingly from other Mesozoic birds, and resembles scansoriopterygids, in the size of the alular metacarpal, the proportions of the manual digits, and the lack of processes on the ischium. These similarities, together with resemblances between basal oviraptorosaurs and previously described scansoriopterygids, may point to a close relationship between these two clades. Cladistic analysis confirms a close relationship between Zhongornis and Scansoriopterygidae, which share forelimbs and pedal unguals that are elongate compared to those of oviraptorosaurs, but does not support oviraptorosaur affinities for this clade. Additional specimens will be required in order to determine both the taxonomic placement of this species and the affinities of Scansoriopterygidae, highlighting the drawbacks of basing new species on juvenile material. 

Key words: Cretaceous, Theropoda, Scansoriopterygidae, Oviraptorosauria, Aves, Zhongornis, tail

Holotype of Zhongornis haoae (D2455 . 6).
Photographs of the slab (left; D2456) and counterslab (right; D2455) under normal light. Interpretive drawing of slab (some portions added from information contained in counterslab) with close-ups of the manus, foot and caudal vertebrae. Abbreviations: co, coracoid; cv, caudal vertebrae (c1–c13); cve, cervical vertebrae; dc, distal carpal; dpc, deltopectoral crest; dv, dorsal vertebrae; gas, gastralia; f, frontal; fei, feather impressions; fem, femur; fib, fibula; fur, furcula; hum, humerus; isc, ischium; j, jugal; mcI–III, metacarpals I–III; mtI–IV, metatarsals I–IV; pmx, premaxilla; q, quadrate; rad, radius; rib, thoracic ribs; sc, scapula; syn, synsacrum; tib, tibia; uln, ulna; I–IV, digits (manual or pedal) I–IV.

illustration: whenpigsfly-returns.blogspot.com

  Zhongornis haoae illustration: Kahless28 on @deviantART 


Jingmai K. O’CONNOR and Corwin SULLIVAN. 2014. Reinterpretation of the Early Cretaceous maniraptoran (Dinosauria: Theropoda) Zhongornis haoae as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs. VERTEBRATA PALASIATICA. 52; 3-30. 

Gao, Cunling, Chiappe, L.M., Meng, Q., O'connor, J.K., Wang, X., Cheng, X., Liu, J. 2008.A New Basal Lineage Of Early Cretaceous Birds From China And Its Implications On The Evolution Of The Avian Tail. Palaeontology. 51(4); 775-791. doi: dx.doi.org/10.1111/j.1475-4983.2008.00793.x


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