与刮伤挖掘机相比,地下哺乳动物的前肢挖掘设备是否具有相似的专业化水平仍然未知。我们评估了所有四只孤立的非洲痣大鼠(Bathyergidae)的肩胛骨形态和前肢肌肉组织:两个刮伤者,Bathyergussuillus和BathyergusJanetta,和两个凿牙挖掘者,隐形虫和八角虫。检测到显着差异:Bathyergus的脖子更健壮,肩膀,和前臂肌肉相比其他属。Bathyergus的一些肌肉也融合了,并且经常显示出更宽的骨骼附着区域,与更坚固和更大的肩胛骨有很好的相关性,和它的更宽和中等取向的鹰嘴。这表明肩膀,弯头,和Bathyergus的腕部协同作用,以产生更大的出力,并且肩胛骨和尺骨近端发挥枢轴的基本作用,以最大化和适应专门的肌肉,以更好地(i)肱骨和肩胛骨稳定,(ii)有力的肩部屈曲,(iii)肘部的伸展和(iv)手肘和手指的弯曲。此外,尽管所有的海卫士都表现出相似的肌肉,Heliophobius缺乏m.张量筋膜前臂(有助于肘部伸展和肱骨收缩),Heliophobius和Georychus缺乏m.oclableshumeri(辅助肱骨内收),表明挖掘组之间的形态发生差异更深,并表明相对较少专门的划痕挖掘能力。然而,Heliophobius和Bathyergus共享一些类似的改编,可以进行划痕挖掘。我们的结果提供了有关该家族内部与专业化相关的形态差异的新信息,以实现不同的功能和挖掘行为,从而有助于理解在系统发育和生态更接近的地下分类群中出现的适应的马赛克。此和先前对Bathyergidae的解剖学研究将为研究人员提供有关肌肉骨骼系统的形式和功能的实质性基础,以便将来对挖掘行为进行运动学研究,以及定义划痕挖掘能力的潜在指标。
Whether the forelimb-digging apparatus of tooth-digging subterranean mammals has similar levels of specialization as compared to scratch-diggers is still unknown. We assessed the scapular morphology and forelimb musculature of all four solitary African mole rats (Bathyergidae): two scratch-diggers, Bathyergus suillus and Bathyergus janetta, and two chisel-tooth diggers, Heliophobius argenteocinereus and Georychus capensis. Remarkable differences were detected: Bathyergus have more robust neck, shoulder, and forearm muscles as compared to the other genera. Some muscles in Bathyergus were also fused and often showing wider attachment areas to bones, which correlate well with its more robust and larger scapula, and its wider and medially oriented olecranon. This suggests that shoulder, elbow, and wrist work in synergy in Bathyergus for generating greater out-forces and that the scapula and proximal ulna play fundamental roles as pivots to maximize and accommodate specialized muscles for better (i) glenohumeral and scapular stabilization, (ii) powerful shoulder flexion, (iii) extension of the elbow and (iv) flexion of the manus and digits. Moreover, although all bathyergids showed a similar set of muscles, Heliophobius lacked the m. tensor fasciae antebrachii (aiding with elbow extension and humeral retraction), and Heliophobius and Georychus lacked the m. articularis humeri (aiding with humeral adduction), indicating deeper morphogenetic differences among digging groups and suggesting a relatively less specialized scratch-digging ability. Nevertheless, Heliophobius and Bathyergus shared some similar adaptations allowing scratch-digging. Our results provide new information about the morphological divergence within this family associated with the specialization to distinct functions and digging behaviors, thus contributing to understand the mosaic of adaptations emerging in phylogenetically and ecologically closer subterranean taxa. This and previous anatomical studies on the Bathyergidae will provide researchers with a substantial basis on the form and function of the musculoskeletal system for future kinematic investigations of digging behavior, as well as to define potential indicators of scratch-digging ability.