CONICET, Argentina; Laboratorio de Morfología Evolutiva y Desarrollo (MORPHOS), Museo de la Plata, Facultad de Ciencias Naturales y Museo, UNLP, Paseo del Bosque s/n, La Plata, Provincia de Buenos Aires, CP. B1900FWA, Argentina.
Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC), Facultad de Ciencias Veterinarias, UNLP, 118 y 60 s/n. La Plata, Provincia de Buenos Aires, CP B1900FWA, Argentina.
Zoology (Jena). 2020 Jun;140:125773. doi: 10.1016/j.zool.2020.125773. Epub 2020 Apr 28.
Vibrissae are specialized and complex mechanoreceptor organs present in the skin of most mammals that respond to a diverse mechanical stimuli (e.g. tension, pressure, movement, vibrations) and provide information on distance to the object, its location/orientation, and general characteristics of its surface; also, it may play diverse roles during food acquisition and attacking potential prey. There are scarce papers on the vibrissae of armadillos, only considering their presence/absence and distribution, but no histological analyses have been made. The goal of our contribution is to perform a histological study of the head vibrissae of Chaetophractus vellerosus, identify their morphological features, the tissues that form them, interpret their possible functions, and attempt to link the characteristics with ecological aspects of this species like its digging habits. Our results suggest that Chaetophractus vellerosus possesses two types of vibrissae: macro- and micro-vibrissae. Both types are similar in gross morphology, characterized mainly by an absence of annular sinus and ringwulst, but having a trabecular sinus that extends along the entire length of the follicle; these features might be linked to a reduction of its sensory capacity. Unlike other mammals, the macro-vibrissae are in the genal, anterobital and intermandibular regions, while micro-vibrissae are distributed in the superior labial and mental regions. In addition to size differences, the macro-vibrissae possess intrinsic muscles composed of smooth muscular fibers. The genal macro-vibrissae are very close to each other, with smooth muscle fibers connecting the capsules of adjacent ones (intrinsic muscles). Those from the superior labial and mental (micro-vibrissae), show bundles of striated muscle inserted on their capsules. These muscle fibers would be part of the facial musculature and could be considered as extrinsic muscles. The mobility of these two types of vibrissae must certainly be different, given that the respective muscles (intrinsic and extrinsic) have different origins and innervation. The presence of two types of vibrissae might indicate that these mechanoreceptors have differential perception capacities that would probably be complementary, thus providing more precise information about the environment. The presence of macro-vibrissae in the genal, anteorbital and intermandibular zone would be directly related to the life habits of Chaetophractus vellerosus.
触须是存在于大多数哺乳动物皮肤中的一种专门且复杂的机械感受器器官，对各种机械刺激（例如张力、压力、运动、振动）做出反应，并提供有关物体距离、位置/方向以及其表面一般特征的信息；此外，在获取食物和攻击潜在猎物时，触须可能发挥多种作用。关于犰狳的触须，仅有少量文献仅考虑其存在/缺失和分布，但尚未进行组织学分析。我们的研究目的是对头部长毛犰狳的触须进行组织学研究，确定其形态特征、形成它们的组织，解释其可能的功能，并尝试将这些特征与该物种的生态方面联系起来，例如挖掘习性。我们的结果表明，长毛犰狳拥有两种类型的触须：macro- 和 micro-vibrissae。这两种类型在宏观形态上相似，主要特征是缺乏环形窦和环状隆凸，但具有贯穿整个滤泡的小梁窦；这些特征可能与感觉能力的降低有关。与其他哺乳动物不同，macro-vibrissae 位于颧骨、前眶和下颌区域，而 micro-vibrissae 则分布在上唇和颏部区域。除了大小差异外，macro-vibrissae 还具有由平滑肌纤维组成的固有肌肉。颧骨上的 macro-vibrissae 彼此非常接近，相邻的胶囊之间有平滑肌纤维相连（固有肌肉）。来自上唇和颏部（micro-vibrissae）的那些则显示出插入其胶囊的横纹肌束。这些肌肉纤维可能是面部肌肉的一部分，可以被视为外在肌肉。由于各自的肌肉（固有和外在）具有不同的起源和神经支配，这两种类型的触须的活动性肯定会有所不同。两种类型的触须的存在可能表明这些机械感受器具有不同的感知能力，这可能是互补的，从而提供有关环境的更精确信息。在颧骨、前眶和下颌区域存在 macro-vibrissae 与长毛犰狳的生活习性直接相关。
