Wednesday, December 21, 2022

[Paleontology • 2022] Europasaurus holgeri • Neurovascular Anatomy of Dwarf Dinosaur implies Precociality in Sauropods


  Europasaurus holgeri Mateus et al. in Sander et al., 2006

Schade, Knötschke, Hörnig, et al., 2022
Life reconstruction by Davide Bonadonna. 

Abstract

Macronaria, a group of mostly colossal sauropod dinosaurs, comprised the largest terrestrial vertebrates of Earth’s history. However, some of the smallest sauropods belong to this group as well. The Late Jurassic macronarian island dwarf Europasaurus holgeri is one of the most peculiar and best-studied sauropods worldwide. So far, the braincase material of this taxon from Germany pended greater attention. With the aid of micro-computed tomography (microCT), we report on the neuroanatomy of the nearly complete braincase of an adult individual, as well as the inner ears (endosseous labyrinths) of one other adult and several juveniles (the latter also containing novel vascular cavities). The presence of large and morphologically adult inner ears in juvenile material suggests precociality. Our findings add to the diversity of neurovascular anatomy in sauropod braincases and buttress the perception of sauropods as fast-growing and autonomous giants with manifold facets of reproductive and social behaviour. This suggests that – apart from sheer size – little separated Europasaurus from its large-bodied relatives.

Life reconstruction of Europasaurus holgeri.
Image credit: Davide Bonadonna (CC BY 4.0)

Marco Schade, Nils Knötschke, Marie K Hörnig, Carina Paetzel and Sebastian Stumpf. 2022. Neurovascular Anatomy of Dwarf Dinosaur implies Precociality in Sauropods. eLife. DOI: 10.7554/eLife.82190
 
Editor's evaluation: 
The authors provide the first detailed description of the neuroanatomy of the remarkable dwarf sauropod Europasaurus from the Jurassic of Germany, which, at least in this regard, was not very different from some of its much larger relatives. The available evidence is compelling and convincing. The comparative sections of the manuscript are solid and provide a relatively broad overview. Based on remains of different individuals and growth stages, the authors suggest that Europasaurus was likely precocial. The authors also assess the likely auditory capabilities and their relevance to the reproductive and social behaviour of this island-dwelling dinosaur.