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The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear.
PLoS One. 2019; 14(2):e0211423.Plos

Abstract

A braincase of the Cretaceous titanosaurian sauropod Malawisaurus dixeyi, complete except for the olfactory region, was CT scanned and a 3D rendering of the endocast and inner ear was generated. Cranial nerves appear in the same configuration as in other sauropods, including derived features that appear to characterize titanosaurians, specifically, an abducens nerve canal that passes lateral to the pituitary fossa rather than entering it. Furthermore, the hypoglossal nerve exits the skull via a single foramen, consistent with most titanosaurians, while other saurischians, including the basal titanosauriform, Giraffatitan, contain multiple rootlets. The size of the vestibular labyrinth is smaller than in Giraffatitan, but larger than in most derived titanosaurians. Similar to the condition found in Giraffatitan, the anterior semicircular canal is larger than the posterior semicircular canal. This contrasts with more derived titanosaurians that contain similarly sized anterior and posterior semicircular canals, congruent with the interpretation of Malawisaurus as a basal titanosaurian. Measurements of the humerus of Malawisaurus provide a body mass estimate of 4.7 metric tons. Comparison of body mass to radius of the semicircular canals of the vestibular labyrinth reveals that Malawisaurus fits the allometric relationship found in previous studies of extant mammals and Giraffatitan brancai. As in Giraffatitan, the anterior semicircular canal is significantly larger than is predicted by the allometric relationship suggesting greater sensitivity and slower movement of the head in the sagittal plane.

Authors+Show Affiliations

Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas, United States of America.Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas, United States of America.Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas, United States of America.Ministry of Civic Education, Culture and Community Development, Lilongwe, Malawi.Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas, United States of America.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30759166

Citation

Andrzejewski, Kate A., et al. "The Braincase of Malawisaurus Dixeyi (Sauropoda: Titanosauria): a 3D Reconstruction of the Brain Endocast and Inner Ear." PloS One, vol. 14, no. 2, 2019, pp. e0211423.
Andrzejewski KA, Polcyn MJ, Winkler DA, et al. The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear. PLoS One. 2019;14(2):e0211423.
Andrzejewski, K. A., Polcyn, M. J., Winkler, D. A., Gomani Chindebvu, E., & Jacobs, L. L. (2019). The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear. PloS One, 14(2), e0211423. https://doi.org/10.1371/journal.pone.0211423
Andrzejewski KA, et al. The Braincase of Malawisaurus Dixeyi (Sauropoda: Titanosauria): a 3D Reconstruction of the Brain Endocast and Inner Ear. PLoS One. 2019;14(2):e0211423. PubMed PMID: 30759166.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear. AU - Andrzejewski,Kate A, AU - Polcyn,Michael J, AU - Winkler,Dale A, AU - Gomani Chindebvu,Elizabeth, AU - Jacobs,Louis L, Y1 - 2019/02/13/ PY - 2018/08/13/received PY - 2019/01/14/accepted PY - 2019/2/14/entrez PY - 2019/2/14/pubmed PY - 2019/11/23/medline SP - e0211423 EP - e0211423 JF - PloS one JO - PLoS One VL - 14 IS - 2 N2 - A braincase of the Cretaceous titanosaurian sauropod Malawisaurus dixeyi, complete except for the olfactory region, was CT scanned and a 3D rendering of the endocast and inner ear was generated. Cranial nerves appear in the same configuration as in other sauropods, including derived features that appear to characterize titanosaurians, specifically, an abducens nerve canal that passes lateral to the pituitary fossa rather than entering it. Furthermore, the hypoglossal nerve exits the skull via a single foramen, consistent with most titanosaurians, while other saurischians, including the basal titanosauriform, Giraffatitan, contain multiple rootlets. The size of the vestibular labyrinth is smaller than in Giraffatitan, but larger than in most derived titanosaurians. Similar to the condition found in Giraffatitan, the anterior semicircular canal is larger than the posterior semicircular canal. This contrasts with more derived titanosaurians that contain similarly sized anterior and posterior semicircular canals, congruent with the interpretation of Malawisaurus as a basal titanosaurian. Measurements of the humerus of Malawisaurus provide a body mass estimate of 4.7 metric tons. Comparison of body mass to radius of the semicircular canals of the vestibular labyrinth reveals that Malawisaurus fits the allometric relationship found in previous studies of extant mammals and Giraffatitan brancai. As in Giraffatitan, the anterior semicircular canal is significantly larger than is predicted by the allometric relationship suggesting greater sensitivity and slower movement of the head in the sagittal plane. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/30759166/The_braincase_of_Malawisaurus_dixeyi__Sauropoda:_Titanosauria_:_A_3D_reconstruction_of_the_brain_endocast_and_inner_ear_ DB - PRIME DP - Unbound Medicine ER -