Department of Anatomy, Animal Production and Veterinary Clinical Sciences, Faculty of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain.
CEMMA Coordinadora para o Estudo dos Mamíferos Mariños. Rúa Ceán, Nigrán, Spain.
Adv Mar Biol. 2023;96:63-83. doi: 10.1016/bs.amb.2023.08.003. Epub 2023 Nov 7.
In the pygmy sperm whale (Kogia breviceps, Blainville 1838), vibrissae are present in neonates, but within a few months the hairs are lost, and the structures remain as empty vibrissal crypts (VCs). In this work, we have studied histologically the facial vibrissal follicles of two juveniles and one adult specimens stranded dead. A few VCs with no visible hairs were found grouped in a row rostral to each eye. The follicular lumen, covered by a simple squamous epithelium, showed invaginations in the most superficial part. Beneath the epithelium, the follicle walls were made of loose connective tissue and were encircled by a thick capsule of dense connective tissue. In juveniles, a dermal papilla was found basally and, from it, a non-keratinized pseudo hair grew upwards but did not reach the skin surface. The VCs were richly innervated and irrigated. Many lamellated corpuscles were identified in the subluminal connective tissue of the crypt walls. A large venous cavernous plexus was located beneath and around the hair papilla. The main differences observed in the adult specimen were the degeneration and calcification of both the dermal papilla and the pseudo hair, and the absence of the venous cavernous plexus, albeit maintaining a rich vascularization and innervation. Our study revealed that VCs of the pygmy sperm whale possess features of fully functional sensory structures, with a microanatomy different from those described in other species. In addition, they undergo a postnatal morphological transformation, which implies functional differences between the VCs of neonates and adults.
在侏儒抹香鲸（Kogia breviceps，Blainville 1838）中，胎生期存在触须，但在几个月内毛发会脱落，而结构则保持为空的触须隐窝（VC）。在这项工作中，我们对搁浅死亡的两个幼年和一个成年标本的面部触须滤泡进行了组织学研究。在每只眼睛的前方，我们发现了一些没有可见毛发的 VC 呈一行聚集。被单层扁平上皮覆盖的滤泡腔在最浅表部分显示出内陷。在上皮下方，滤泡壁由疏松结缔组织构成，并被致密结缔组织的厚囊环绕。在幼年个体中，在基部发现了一个真皮乳头，从其向上生长出一根非角质化的假毛，但未到达皮肤表面。VC 富含神经和血管。在隐窝壁的皮下结缔组织中鉴定出许多板层小体。一个大的静脉海绵状丛位于毛乳头下方和周围。在成年标本中观察到的主要差异是真皮乳头和假毛的退化和钙化，以及静脉海绵状丛的缺失，尽管仍保持丰富的血管和神经支配。我们的研究表明，侏儒抹香鲸的 VC 具有完全功能性感觉结构的特征，其微观解剖结构与其他物种描述的不同。此外，它们经历了产后形态转化，这意味着新生和成年 VC 之间存在功能差异。
