Author(s) |
Klinkhamer, Ada J
Mallison, Heinrich
Poropat, Stephen F
Sloan, Trish
Wroe, Stephen
|
Publication Date |
2019-05
|
Abstract |
The evolution of extraordinarily large size among Sauropoda was associated with a number of biomechanical adaptations. Changes in muscle moment arms undoubtedly accompanied these adaptations, but since muscles rarely fossilize, our ability to understand them has been restricted. Here, we use three-dimensional (3D) musculoskeletal modeling to reconstruct and quantitatively assess leverage of forelimb muscles in the transition from the narrow-gauge stance of basal sauropods to a wide-gauge stance in titanosaurs. A comparative analysis is conducted on three neosauropods: the narrow-gauge diplodocid <i>Apatosaurus louisae</i>, the intermediate-gauge titanosariform <i>Giraffatitan brancai</i>, and the wide-gauge titanosaur <i>Diamantinasaurus matildae</i>. In this study, moment arm magnitudes and corresponding morphological evidence indicates multiple changes across the narrow-gauge to wide-gauge transition in sauropods. High shoulder adduction was found in <i>Diamantinasaurus</i>, suggesting functional changes for supporting a wider stance and a limb less aligned with ground reaction force. High leverage in shoulder extension of <i>Diamantinasaurus</i> and <i>Giraffatitan</i> is possibly related to the increased use of the forelimb in forward propulsion with an anterior shift in center of mass. In addition, the prominence of the olecranon process in <i>Diamantinasaurus</i> produced high moment arm leverage in elbow flexion and extension, suggesting titanosaurs might have maintained a more flexed forelimb posture and displayed an increased degree of maneuverability. Other results are more variable between taxa but still indicate smaller scale changes. A sensitivity analysis was also conducted to measure the reliability of our models and test specific uncertainties within the modeling process, as well as other uncertainties uncovered during analysis.
|
Citation |
The Anatomical Record, 302(5), p. 794-817
|
ISSN |
1932-8494
1932-8486
|
Pubmed ID |
30315633
|
Link | |
Publisher |
John Wiley & Sons, Inc
|
Title |
Comparative Three-Dimensional Moment Arm Analysis of the Sauropod Forelimb: Implications for the Transition to a Wide-Gauge Stance in Titanosaurs
|
Type of document |
Journal Article
|
Entity Type |
Publication
|
Name | Size | format | Description | Link |
---|