Department of Anthropology, The Graduate Center at the City University of New York, New York, 10016; New York Consortium in Evolutionary Primatology, New York, New York.
Anat Rec (Hoboken). 2013 Dec;296(12):1881-94. doi: 10.1002/ar.22828.
This study investigates the vomeronasal organ in extant nocturnal strepsirhines as a model for ancestral primates. Cadaveric samples from 10 strepsirhine species, ranging from fetal to adult ages, were studied histologically. Dimensions of structures in the vomeronasal complex, such as the vomeronasal neuroepithelium (VNNE) and vomeronasal cartilage (VNC) were measured in serial sections and selected specimens were studied immunohistochemically to determine physiological aspects of the vomeronasal sensory neurons (VSNs). Osteological features corresponding to vomeronasal structures were studied histologically and related to 3-D CT reconstructions. The VNC consistently rests in a depression on the palatal portion of the maxilla, which we refer to as the vomeronasal groove (VNG). Most age comparisons indicate that in adults VNNE is about twice the length compared with perinatal animals. In VNNE volume, adults are 2- to 3-fold larger compared with perinatal specimens. Across ages, a strong linear relationship exists between VNNE dimensions and body length, mass, and midfacial length. Results indicate that the VNNE of nocturnal strepsirhines is neurogenic postnatally based on GAP43 expression. In addition, based on Olfactory Marker Protein expression, terminally differentiated VSNs are present in the VNNE. Therefore, nocturnal strepsirhines have basic similarities to rodents in growth and maturational characteristics of VSNs. These results indicate that a functional vomeronasal system is likely present in all nocturnal strepsirhines. Finally, given that osteological features such as the VNG are visible on midfacial bones, primate fossils can be assessed to determine whether primate ancestors possessed a vomeronasal complex morphologically similar to that of modern nocturnal strepsirhines.
本研究以现生的夜行性食虫目动物的犁鼻器为模型来研究祖先灵长类的犁鼻器。我们对 10 种食虫目动物的尸体样本进行了组织学研究，这些样本的年龄从胎儿到成年不等。我们在连续切片中测量了犁鼻器复合体结构的尺寸，例如犁鼻神经上皮（VNNE）和犁鼻软骨（VNC），并对选定的标本进行了免疫组织化学研究，以确定犁鼻感觉神经元（VSN）的生理方面。我们还对与犁鼻器结构相对应的骨骼特征进行了组织学研究，并与 3D CT 重建相关联。VNC 始终位于上颌骨腭部的凹陷处，我们将这个凹陷称为犁鼻沟（VNG）。大多数年龄比较表明，在成年动物中，VNNE 的长度大约是围产期动物的两倍。在 VNNE 体积方面，成年动物比围产期标本大 2-3 倍。在各个年龄段，VNNE 的尺寸与身体长度、体重和中面部长度之间存在强烈的线性关系。结果表明，基于 GAP43 的表达，夜行性食虫目动物的犁鼻神经上皮在出生后具有神经发生能力。此外，基于嗅觉标记蛋白的表达，终末分化的 VSN 存在于 VNNE 中。因此，夜行性食虫目动物在 VSN 的生长和成熟特征方面与啮齿动物具有基本的相似性。这些结果表明，所有夜行性食虫目动物都可能具有功能完整的犁鼻器系统。最后，鉴于 VNG 等骨骼特征在上颌骨的中面部可见，因此可以评估灵长类化石，以确定灵长类祖先是否具有与现代夜行性食虫目动物相似的犁鼻器复合体形态。
