Zollikofer Christoph P E, Scherrer Marc, Ponce de León Marcia S
Anthropological Institute and Museum, University of Zurich, Zurich, CH-8057, Switzerland.
Anat Rec (Hoboken). 2017 May;300(5):859-869. doi: 10.1002/ar.23556.
Pelvic sexual dimorphism in primates is typically seen as the result of female-specific adaptations to obstetric constraints, which arise from the tight fit between the neonate head and the maternal pelvis. However, it remains debated to which extent pelvic dimorphism is a correlate of obstetric constraints, of body size dimorphism, and/or of other factors. Also, little is known on how pelvic dimorphism develops. Here we use methods of biomedical imaging and geometric morphometrics to address these questions in two hylobatid species, Hylobates lar and Symphalangus syndactylus. These species differ markedly in body size, but within each species, there is only little body size dimorphism. Results show that the neonates of H. lar are large compared to the maternal pelvis, resulting in high cephalopelvic proportions and substantial obstetric constraints. Pelvic sexual dimorphism is moderate but significant: During puberty, females develop a more capacious pelvic inlet than males, while overall pelvic size is similar in both sexes. S. syndactylus has substantially larger pelves than H. lar, but neonates are similar in size to those of H. lar. Cephalopelvic proportions are thus low, and there are no obstetric constraints. Pelvic sexual dimorphism is absent. Overall, these data indicate that pelvic sexual dimorphism in hylobatids reflects obstetric constraints. Anat Rec, 300:859-869, 2017. © 2017 Wiley Periodicals, Inc.
灵长类动物的骨盆两性异形通常被视为雌性对产科限制的特定适应性结果，这种限制源于新生儿头部与母体骨盆之间的紧密契合。然而，骨盆两性异形在多大程度上与产科限制、体型两性异形和/或其他因素相关，仍存在争议。此外，关于骨盆两性异形如何发展也知之甚少。在这里，我们使用生物医学成像和几何形态测量学方法，在两种长臂猿物种——白掌长臂猿（Hylobates lar）和合趾猿（Symphalangus syndactylus）中解决这些问题。这些物种在体型上有显著差异，但在每个物种内部，体型两性异形很小。结果表明，与母体骨盆相比，白掌长臂猿的新生儿体型较大，导致头盆比例较高和严重的产科限制。骨盆两性异形适中但显著：在青春期，雌性的骨盆入口比雄性更宽大，而两性的总体骨盆大小相似。合趾猿的骨盆比白掌长臂猿大得多，但新生儿的体型与白掌长臂猿的相似。因此，头盆比例较低，不存在产科限制。骨盆两性异形不存在。总体而言，这些数据表明长臂猿的骨盆两性异形反映了产科限制。《解剖学记录》，300:859 - 869，2017年。© 2017威利期刊公司。
