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Unique suites of trabecular bone features characterize locomotor behavior in human and non-human anthropoid primates.

Ryan TM, Shaw CN - PLoS ONE (2012)

Bottom Line: Understanding the mechanically-mediated response of trabecular bone to locomotion-specific loading patterns would be of great benefit to comparative mammalian evolutionary morphology.Discriminant function analyses reveal that subarticular trabecular bone in the femoral and humeral heads is significantly different among most locomotor groups.The results indicate that when a suite of femoral head trabecular features is considered, trabecular number and connectivity density, together with fabric anisotropy and the relative proportion of rods and plates, differentiate locomotor groups reasonably well.

View Article: PubMed Central - PubMed

Affiliation: Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, United States of America. tmr21@psu.edu

ABSTRACT
Understanding the mechanically-mediated response of trabecular bone to locomotion-specific loading patterns would be of great benefit to comparative mammalian evolutionary morphology. Unfortunately, assessments of the correspondence between individual trabecular bone features and inferred behavior patterns have failed to reveal a strong locomotion-specific signal. This study assesses the relationship between inferred locomotor activity and a suite of trabecular bone structural features that characterize bone architecture. High-resolution computed tomography images were collected from the humeral and femoral heads of 115 individuals from eight anthropoid primate genera (Alouatta, Homo, Macaca, Pan, Papio, Pongo, Trachypithecus, Symphalangus). Discriminant function analyses reveal that subarticular trabecular bone in the femoral and humeral heads is significantly different among most locomotor groups. The results indicate that when a suite of femoral head trabecular features is considered, trabecular number and connectivity density, together with fabric anisotropy and the relative proportion of rods and plates, differentiate locomotor groups reasonably well. A similar, yet weaker, relationship is also evident in the trabecular architecture of the humeral head. The application of this multivariate approach to analyses of trabecular bone morphology in recent and fossil primates may enhance our ability to reconstruct locomotor behavior in the fossil record.

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Results of multivariate discriminant function analyses for the humeral head.Symbols as in Figure 2.
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pone-0041037-g003: Results of multivariate discriminant function analyses for the humeral head.Symbols as in Figure 2.

Mentions: The analysis of trabecular morphology of the proximal humerus also generated two significant discriminant functions (p<0.001) that accounted for 64.2% and 21.6% of the variance, respectively (Figure 3). These functions correctly classify 67 of the 115 specimens (58.3%) into their assigned locomotor groups, but the percentage of correct classifications varies by group (Table 6). Function 1 is strongly correlated with Tb.N and SMI, while Function 2 correlate with SMI and Conn.D (Table 7). Function 1 differentiates terrestrial quadrupeds and terrestrial quadrupedal-climbers (Papio, and Pan, respectively) from bipeds, quadrumanous climbers and arboreal quadrupedal-climbers (Homo, Pongo, Alouatta, respectively). Arboreal quadrupeds (Macaca and Trachypithecus) and brachiators (Symphalangus) overlap with all other groups. In contrast, for Function 2 brachiators (Symphalangus) are virtual outliers, separated from all other groups that are tightly clustered. Additionally, an F-test of between-group separations is significant among all locomotor groups (p<0.001, Table 8) other than bipeds and quadrumanous climbers. Similar to the outcome of the stepwise F-test conducted for femoral head trabecular analyses, the humeral head analysis initially included all five Tb variables. However, because SMI and Tb.Th are not included in the ‘best fit’ final solution, between group differences are based on only three variables, DA, Tb.N and Conn.D.


Unique suites of trabecular bone features characterize locomotor behavior in human and non-human anthropoid primates.

Ryan TM, Shaw CN - PLoS ONE (2012)

Results of multivariate discriminant function analyses for the humeral head.Symbols as in Figure 2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3399801&req=5

pone-0041037-g003: Results of multivariate discriminant function analyses for the humeral head.Symbols as in Figure 2.
Mentions: The analysis of trabecular morphology of the proximal humerus also generated two significant discriminant functions (p<0.001) that accounted for 64.2% and 21.6% of the variance, respectively (Figure 3). These functions correctly classify 67 of the 115 specimens (58.3%) into their assigned locomotor groups, but the percentage of correct classifications varies by group (Table 6). Function 1 is strongly correlated with Tb.N and SMI, while Function 2 correlate with SMI and Conn.D (Table 7). Function 1 differentiates terrestrial quadrupeds and terrestrial quadrupedal-climbers (Papio, and Pan, respectively) from bipeds, quadrumanous climbers and arboreal quadrupedal-climbers (Homo, Pongo, Alouatta, respectively). Arboreal quadrupeds (Macaca and Trachypithecus) and brachiators (Symphalangus) overlap with all other groups. In contrast, for Function 2 brachiators (Symphalangus) are virtual outliers, separated from all other groups that are tightly clustered. Additionally, an F-test of between-group separations is significant among all locomotor groups (p<0.001, Table 8) other than bipeds and quadrumanous climbers. Similar to the outcome of the stepwise F-test conducted for femoral head trabecular analyses, the humeral head analysis initially included all five Tb variables. However, because SMI and Tb.Th are not included in the ‘best fit’ final solution, between group differences are based on only three variables, DA, Tb.N and Conn.D.

Bottom Line: Understanding the mechanically-mediated response of trabecular bone to locomotion-specific loading patterns would be of great benefit to comparative mammalian evolutionary morphology.Discriminant function analyses reveal that subarticular trabecular bone in the femoral and humeral heads is significantly different among most locomotor groups.The results indicate that when a suite of femoral head trabecular features is considered, trabecular number and connectivity density, together with fabric anisotropy and the relative proportion of rods and plates, differentiate locomotor groups reasonably well.

View Article: PubMed Central - PubMed

Affiliation: Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, United States of America. tmr21@psu.edu

ABSTRACT
Understanding the mechanically-mediated response of trabecular bone to locomotion-specific loading patterns would be of great benefit to comparative mammalian evolutionary morphology. Unfortunately, assessments of the correspondence between individual trabecular bone features and inferred behavior patterns have failed to reveal a strong locomotion-specific signal. This study assesses the relationship between inferred locomotor activity and a suite of trabecular bone structural features that characterize bone architecture. High-resolution computed tomography images were collected from the humeral and femoral heads of 115 individuals from eight anthropoid primate genera (Alouatta, Homo, Macaca, Pan, Papio, Pongo, Trachypithecus, Symphalangus). Discriminant function analyses reveal that subarticular trabecular bone in the femoral and humeral heads is significantly different among most locomotor groups. The results indicate that when a suite of femoral head trabecular features is considered, trabecular number and connectivity density, together with fabric anisotropy and the relative proportion of rods and plates, differentiate locomotor groups reasonably well. A similar, yet weaker, relationship is also evident in the trabecular architecture of the humeral head. The application of this multivariate approach to analyses of trabecular bone morphology in recent and fossil primates may enhance our ability to reconstruct locomotor behavior in the fossil record.

Show MeSH