Juxtaligamental cells in the arm of the brittlestar Amphipholis kochii Lütken, 1872 (Echinodermata: Ophiuroidea)

Abstract

We found that ligaments connecting the skeletal elements in the arm of the brittlestar Amphipholis kochii, consisted of mutable collagenous tissue (MCT), whose basichistological character is that of numerous processes of juxtaligamental cells penetrating the extracellular matrix. These cells are located in the hyponeural neuroepithelium associated with hyponeural nerves, and were also recorded in the spine ganglia and basiepithelial nervous plexus in the coelomic epithelium. The distinctive feature of juxtaligamental cells is the presence of electron-dense granules in their cytoplasm and a well developed synthetic apparatus. Based on personal and literature data it is concluded that juxtaligamental cells are a part of the nervous system, and their basic function is related to providing MCT with innervation.