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The endocranial anatomy of therizinosauria and its implications for sensory and cognitive function.

Lautenschlager S, Rayfield EJ, Altangerel P, Zanno LE, Witmer LM - PLoS ONE (2012)

Bottom Line: This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory.The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon.In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Bristol, United Kingdom. glzsl@bristol.ac.uk

ABSTRACT

Background: Therizinosauria is one of the most enigmatic and peculiar clades among theropod dinosaurs, exhibiting an unusual suite of characters, such as lanceolate teeth, a rostral rhamphotheca, long manual claws, and a wide, opisthopubic pelvis. This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory. Despite a large number of discoveries in recent years, the fossil record for Therizinosauria is still relatively poor, and cranial remains are particularly rare.

Methodology/principal findings: Based on computed tomographic (CT) scanning of the nearly complete and articulated skull of Erlikosaurus andrewsi, as well as partial braincases of two other therizinosaurian taxa, the endocranial anatomy is reconstructed and described. The wider phylogenetic range of the described specimens permits the evaluation of sensory and cognitive capabilities of Therizinosauria in an evolutionary context. The endocranial anatomy reveals a mosaic of plesiomorphic and derived characters in therizinosaurians. The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon.

Conclusion/significance: This study presents the first appraisal of the evolution of endocranial anatomy and sensory adaptations in Therizinosauria. Despite their phylogenetically basal position among maniraptoran dinosaurs, therizinosaurians had developed the neural pathways for a well developed sensory repertoire. In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.

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In-situ endocranial elements of the described therizinosaurian taxa displayed in their phylogenetic context.Bone rendered transparent to reveal endocranial anatomy. (Phylogeny modified from [4]).
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pone-0052289-g001: In-situ endocranial elements of the described therizinosaurian taxa displayed in their phylogenetic context.Bone rendered transparent to reveal endocranial anatomy. (Phylogeny modified from [4]).

Mentions: Based on the endocasts of these four specimens, we present an extensive description of the endocranial anatomy of therizinosaurians (Figure 1). The wide phylogenetic range of these samples, spanning both basal and derived taxa and thus a considerable part of the known therizinosaurian diversity, allows inferences to be drawn about sensory and cognitive capabilities. It further provides the foundation for the study of endocranial and sensorineural evolution in Therizinosauria. This is potentially relevant to the discussion of whether therizinosaurian sensory (and cognitive) abilities were specially adapted to herbivory.


The endocranial anatomy of therizinosauria and its implications for sensory and cognitive function.

Lautenschlager S, Rayfield EJ, Altangerel P, Zanno LE, Witmer LM - PLoS ONE (2012)

In-situ endocranial elements of the described therizinosaurian taxa displayed in their phylogenetic context.Bone rendered transparent to reveal endocranial anatomy. (Phylogeny modified from [4]).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3526574&req=5

pone-0052289-g001: In-situ endocranial elements of the described therizinosaurian taxa displayed in their phylogenetic context.Bone rendered transparent to reveal endocranial anatomy. (Phylogeny modified from [4]).
Mentions: Based on the endocasts of these four specimens, we present an extensive description of the endocranial anatomy of therizinosaurians (Figure 1). The wide phylogenetic range of these samples, spanning both basal and derived taxa and thus a considerable part of the known therizinosaurian diversity, allows inferences to be drawn about sensory and cognitive capabilities. It further provides the foundation for the study of endocranial and sensorineural evolution in Therizinosauria. This is potentially relevant to the discussion of whether therizinosaurian sensory (and cognitive) abilities were specially adapted to herbivory.

Bottom Line: This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory.The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon.In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Bristol, United Kingdom. glzsl@bristol.ac.uk

ABSTRACT

Background: Therizinosauria is one of the most enigmatic and peculiar clades among theropod dinosaurs, exhibiting an unusual suite of characters, such as lanceolate teeth, a rostral rhamphotheca, long manual claws, and a wide, opisthopubic pelvis. This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory. Despite a large number of discoveries in recent years, the fossil record for Therizinosauria is still relatively poor, and cranial remains are particularly rare.

Methodology/principal findings: Based on computed tomographic (CT) scanning of the nearly complete and articulated skull of Erlikosaurus andrewsi, as well as partial braincases of two other therizinosaurian taxa, the endocranial anatomy is reconstructed and described. The wider phylogenetic range of the described specimens permits the evaluation of sensory and cognitive capabilities of Therizinosauria in an evolutionary context. The endocranial anatomy reveals a mosaic of plesiomorphic and derived characters in therizinosaurians. The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon.

Conclusion/significance: This study presents the first appraisal of the evolution of endocranial anatomy and sensory adaptations in Therizinosauria. Despite their phylogenetically basal position among maniraptoran dinosaurs, therizinosaurians had developed the neural pathways for a well developed sensory repertoire. In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.

Show MeSH