Complex overlapping joints between facial bones allowing limited anterior sliding movements of the snout in diplodocid sauropods

Title Variants

Alternative: Sliding joints in diplodocid skulls

Related Titles

Series: American Museum novitates, number 3911

By

Tschopp, Emanuel , author

Mateus, Octávio , author
Norell, Mark A. , author

Type

Book

Material

Published material

Publication info

New York, NY American Museum of Natural History [2018]

Notes

Caption title.

"October 25, 2018."

Specimen collected in 2016 at Cosm Quarry, a late Jurassic locality from the the upper Morrison Formation in the northern Bighorn Basin, northern Wyoming. (Page 2)

Diplodocid sauropods had a unique skull morphology, with posteriorly retracted nares, an elongated snout, and anteriorly restricted, peglike teeth. Because of the lack of extant analogs in skull structure and tooth morphology, understanding their feeding strategy and diet has been difficult. Furthermore, the general rarity of sauropod skulls and the fragility of their facial elements resulted in a restricted knowledge of cranial anatomy, in particular regarding the internal surface of the facial skull. Here, we describe in detail a well-preserved diplodocid skull visible in medial view. Diagnostic features recognized in other skulls observable in lateral view, such as the extended contribution of the jugal to the antorbital fenestra, are obliterated in medial view due to extensive overlapping joints between the maxilla, jugal, quadratojugal, and the lacrimal. These overlapping joints permitted limited anterior sliding movement of the snout, which likely served as a kind of "shock-absorbing" mechanism during feeding. Diplodocid skulls therefore seem to have evolved to alleviate stresses inflicted on the snout during backward movements of the head, as would be expected during branch-stripping or raking.

Subjects

Anatomy , Diplodocidae , Facial bones , Joints , Jurassic , Morrison Formation , Paleontology , Reptiles, Fossil , Skull , Wyoming

Call Number

QL1 .A436 no.3911 2018

Language

English

Identifiers

DOI: https://doi.org/10.1206/3911.1
OCLC: 1057815429