Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice, 37005, Czech Republic.
Department of Biological Sciences, University of Cape Town, Private Bag X3, Rhodes Gift 7701, Cape Town, South Africa.
Commun Biol. 2022 Jun 1;5(1):526. doi: 10.1038/s42003-022-03480-z.
Life underground has constrained the evolution of subterranean mammals to maximize digging performance. However, the mechanisms modulating morphological change and development of fossorial adaptations in such taxa are still poorly known. We assessed the morpho-functional diversity and early postnatal development of fossorial adaptations (bone superstructures) in the appendicular system of the African mole-rats (Bathyergidae), a highly specialized subterranean rodent family. Although bathyergids can use claws or incisors for digging, all genera presented highly specialized bone superstructures associated with scratch-digging behavior. Surprisingly, Heterocephalus glaber differed substantially from other bathyergids, and from fossorial mammals by possessing a less specialized humerus, tibia and fibula. Our data suggest strong functional and developmental constraints driving the selection of limb specializations in most bathyergids, but more relaxed pressures acting on the limbs of H. glaber. A combination of historical, developmental and ecological factors in Heterocephalus are hypothesized to have played important roles in shaping its appendicular phenotype.
地下生活限制了地下哺乳动物的进化，以最大限度地提高挖掘性能。然而，调节形态变化和此类分类群挖掘适应发展的机制仍知之甚少。我们评估了非洲鼹鼠（Bathyergidae）附肢系统中挖掘适应（骨骼超结构）的形态功能多样性和早期产后发育，非洲鼹鼠是一种高度专门化的地下啮齿动物家族。尽管鼹鼠科可以使用爪子或门齿进行挖掘，但所有属都表现出与划痕挖掘行为相关的高度专门化的骨骼超结构。令人惊讶的是，Heterocephalus glaber 与其他鼹鼠科动物以及其他挖掘哺乳动物有很大的不同，它的肱骨、胫骨和腓骨的专门化程度较低。我们的数据表明，强烈的功能和发育约束驱动着大多数鼹鼠科动物的肢体特化选择，但对 H. glaber 肢体的压力更为宽松。历史、发育和生态因素的结合在 Heterocephalus 中可能发挥了重要作用，塑造了其附肢表型。
