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The first dimension explained most of the covariation between shape and geography on the unadjusted coordinates
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Geographic variation is an important feature among primates, but the mechanisms underlying it are not well understood. Macaques are geographically widespread and have been translocated to captive populations, providing a prime opportunity to evaluate changes in cranial form in response to a novel environment. Clinal variation was assesse...
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... unadjusted geographic shape, ABSlat remained the most important factor, but in adjusted geographic shape the contribution of precipitation and ABSlat were approximately equal. Overall, environmental variables explained more of the variation for unadjusted geographic shape than for adjusted geographic shape, consistent with the results of the 2B-PLS, which also found a less tightly correlated relationship between cranial shape and geography when variation due to size and sex was corrected for ( Figure 6; Table 4). Thus, variation in shape due to size and sex is also likely to be geographically variable. ...Citations
... Morphological variation driven by environmental factors may require revisions to this taxonomy. Recent studies have highlighted the utility of captive/wild comparison studies for understanding phenotypically plastic morphological differences between populations of wild animals, and thus the criteria for subspecific taxonomy [15,16]. Boundaries of subspecies, recognised and defined by morphological differences, influence conservation management and so have real, practical importance for the future of these species. ...
Zoo animals are crucial for conserving and potentially re-introducing species to the wild, yet it is known that the morphology of captive animals differs from that of wild animals. It is important to know how and why zoo and wild animal morphology differs to better care for captive animals and enhance their survival in reintroductions, and to understand how plasticity may influence morphology, which is supposedly indicative of evolutionary relationships. Using museum collections, we took 56 morphological measurements of skulls and mandibles from 617 captive and wild lions and tigers, reflecting each species’ recent historical range. Linear morphometrics were used to identify differences in size and shape. Skull size does not differ between captive and wild lions and tigers, but skull and mandible shape does. Differences occur in regions associated with biting, indicating that diet has influenced forces acting upon the skull and mandible. The diets of captive big cats used in this study predominantly consisted of whole or partial carcasses, which closely resemble the mechanical properties of wild diets. Thus, we speculate that the additional impacts of killing, manipulating and consuming large prey in the wild have driven differentiation between captive and wild big cats.
... This contrasts with studies of African monkeys that highlight the generally greater influence of rainfall over temperature in skull morphology (Cardini et al., 2007;Cardini et al., 2010;Dunn et al., 2013). Our findings also deviate from those of a recent study of predominantly long-tailed macaques and other closely related species, which found a relationship between cranial shape and rainfall and temperature only outside the tropics and which did not detect a significant effect of rainfall and temperature on male cranial size (Arenson et al., 2022). Latitudinal trends in M. fascicularis skull length may not be linked to temperature gradients (Schillaci et al., 2009;Arenson et al., 2022) but our findings demonstrate that temperature is an important influence on morphology, even if that is not linked to geography. ...
... Our findings also deviate from those of a recent study of predominantly long-tailed macaques and other closely related species, which found a relationship between cranial shape and rainfall and temperature only outside the tropics and which did not detect a significant effect of rainfall and temperature on male cranial size (Arenson et al., 2022). Latitudinal trends in M. fascicularis skull length may not be linked to temperature gradients (Schillaci et al., 2009;Arenson et al., 2022) but our findings demonstrate that temperature is an important influence on morphology, even if that is not linked to geography. The slightly higher classification rates for subspecies based on cranial compared to mandibular morphology detected in our study may indicate that the cranium probably carries non-environmental signals, like population history, but the mandible and cranium had very similar coefficients of determination in the environmental analysis. ...
