segunda-feira, dezembro 08, 2008

Manada de ornitomimossauros apanhados numa armadilha de lama

A revista Acta Palaeontologica Polonica dá-nos conta de uma manada de cerca de 20 ornitomimossauros apanhados numa armadilha de lama na China.

Abstract: A unique dinosaur assemblage from the Cretaceous beds of western Inner Mongolia preserves geologic and paleontologic data that clearly delineate both the timing and mechanism of death. Over twenty individuals of the ornithomimid Sinornithomimus dongi perished while trapped in the mud of a drying lake or pond, the proximity and alignment of the mired skeletons indicating a catastrophic mass mortality of a social group. Histologic examination reveals the group to consist entirely of immature individuals between one and seven years of age, with no hatchlings or mature individuals.
The Sinornithomimus locality supports the interpretation of other, more taphonomically ambiguous assemblages of immature dinosaurs as reflective of juvenile sociality. Adults of various nonavian dinosaurs are known to have engaged in prolonged nesting and post hatching parental care, a life history strategy that implies juveniles spent considerable time away from reproductively active adults. Herding of juveniles, here documented in a Cretaceous ornithomimid, may have been a common life history strategy among nonavian dinosaurs reflecting their oviparity, extensive parental care, and multi−year maturation.

Parabéns aos autores. A descoberta,  sem dúvida espectacular, foi inicialmente identificada por Yoshitsugu Kobayashi e Jun-Chang Lü em 2003.  Neste novo artigo obviamente não foi publicada a curiosa história de bastidores que explica como é que os descobridores iniciais foram "ultrapassados" e não fazem parte deste artigo.

D. J. Varricchio, et al.  2008. Mud-trapped herd captures evidence of distinctive dinosaur sociality. 2008. Acta Palaeontologica Polonica 53 (4), 2008: 567-578. PDF
Yoshitsugu Kobayashi and Jun-Chang Lü 2003 A new ornithomimid dinosaur with gregarious habits from the Late Cretaceous of China. Acta Palaeontologica Polonica 48 (2), 2003: 235-259. 


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