On the fine structure of the skin of larval, juvenile and adult Ichthyophis (Amphibia, Caecilia)

Abstract

The skin of a number of larvae at different developmental stages (in part determined by the level of differentiation of a variety of skin components), of a juvenile 9–10 cm specimen and of adults of Ichthyophis was examined by electron microscopy. More important results include descriptions of (a) the larval Leydig cells and their differentiation; (b) the fully developed Merkel cells and their synaptic association in older larvae and the postmetamorphic forms; (c) the structure and arrangement of the postmetamorphic flask cells and their associated nerves in the epidermis; (d) the relatively early development and differentiation of the mucous and granular glands in the dermis of the larva, comparable with those of adults; (e) the presence of iridophores in the dermis of the juvenile specimen and their relationship with the laminophore type cells. Some comparisons are made with previous descriptions of young larval and adult skin of Ichthyophis. The level of cellular differentiation of Leydig cells, Merkel cells and the glands would imply that they were fully functional in older premetamorphic larvae of Ichthyophis: indeed these components are recognizable, albeit in immature form, in young larvae 4.5 cm long.