[dinosaur] Avimimid birdlike growth and mixed-age flocks (free pdf)

Ben Creisler
[email protected]

A new paper in open access:


G. F. Funston, P. J. Currie, M. J. Ryan & Z.-M. Dong (2019)
Birdlike growth and mixed-age flocks in avimimids (Theropoda,
Oviraptorosauria).
Scientific Reports 9, Article number: 18816
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1038_s41598-2D019-2D55038-2D5&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=0eY9JKFbQYZ4d7K07y6HrP_TzqGOYF4J1ZIRgQMf0E4&s=JnvHNKTyqk0wA6oLz1HIyrUzsQHjOGDQBekhUwLMutw&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41598-2D019-2D55038-2D5&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=0eY9JKFbQYZ4d7K07y6HrP_TzqGOYF4J1ZIRgQMf0E4&s=gkFsB0b-wkPm25LoStaGBYKK-rjLpoyV7_W6ep9VGRQ&e= 

Free pdf:
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41598-2D019-2D55038-2D5.pdf&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=0eY9JKFbQYZ4d7K07y6HrP_TzqGOYF4J1ZIRgQMf0E4&s=wD3NUAy7vV54wZ1ggrzb3KvATI93ldgqaCFkuksM70Y&e= 



Avimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous
of Asia. Initially enigmatic, new information has ameliorated the
understanding of their anatomy, phylogenetic position, and behaviour. A
monodominant bonebed from the Nemegt Formation of Mongolia showed that some
avimimids were gregarious, but the site is unusual in the apparent absence
of juveniles. Here, a second monodominant avimimid bonebed is described
from the Iren Dabasu Formation of northern China. Elements recovered
include numerous vertebrae and portions of the forelimbs and hindlimbs,
representing a minimum of six individuals. Histological sampling of two
tibiotarsi from the bonebed reveals rapid growth early in ontogeny followed
by unexpectedly early onset of fusion and limited subsequent growth. This
indicates that avimimids grew rapidly to adult size, like most extant birds
but contrasting other small theropod dinosaurs. The combination of adults
and juveniles in the Iren Dabasu bonebed assemblage provides evidence of
mixed-age flocking in avimimids and the onset of fusion in young
individuals suggests that some of the individuals in the Nemegt Formation
bonebed may have been juveniles. Regardless, these individuals were likely
functionally analogous to adults, and this probably facilitated mixed-age
flocking by reducing ontogenetic niche shift in avimimids.