[dinosaur] Macrogryphosaurus osteology (ornithopod from Upper Cretaceous of Argentina)

Ben Creisler
[email protected]

A new paper:

Sebastián Rozadilla, Penélope Cruzado-Caballero & Jorge O.Calvo (2019)
Osteology of Ornithopod Macrogryphosaurus gondwanicus (Dinosauria,
Ornithischia) from the Upper Cretaceous of Patagonia, Argentina.
Cretaceous Research (advance online publication)
doi:  https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.cretres.2019.104311&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=pID3u1r2wUvcXp498TBwKXZ_VgMHjFkLcploPi5awyw&s=MVRw8Htb92ygb4IKwpN4DcbZeGfgCn12Jwr_gEz2YeI&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S0195667119302460&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=pID3u1r2wUvcXp498TBwKXZ_VgMHjFkLcploPi5awyw&s=yLzUBR9Pc4XmcsYQxcQby-JFVtaXpC108_f_AYPQdco&e= 


Macrogryphosaurus gondwanicus is the largest Elasmaria (Dinosauria,
Ornithischia) known up to the date, from the Upper Cretaceous of Patagonia.
The present contribution provides a detailed description of
Macrogryphosaurus anatomy based on the holotype and only known specimen.
This dinosaur presents several unique features along its vertebral column
that distinguishes it from other ornithopods: the neck is notably elongated
by the acquisition of an additional cervical vertebra, having 10 cervical
plus 14 dorsal vertebrae, being the number of dorsals minor than in other
taxa, which usually have 16. This implies that Macrogryphosaurus represents
a new ornithopod morphotype, with long neck and short thorax. Moreover,
three autapomorphies are here added to the original diagnosis of
Macrogryphosaurus: presence of poorly developed diapophyses in the cervical
vertebrae, anterior and posterior processes on the boat-shaped haemal
arches, and a pubic foot in the postpubic process. The dorsoventral length
of haemal arches indicate the ventral limit of the M. caudofemoralis longus
and their posterior tapering so as the dorsal limit of the M.
ilio-ischiocaudalis and its posterior ascension and dominance in the
posterior-most portion of tail, resembling to the tail of some coelurosaur
dinosaurs.