Xanthophore Migration from the Dermis to the Epidermis and Dermal Remodeling During Salamandra salamandra salamandra (L.) Larval Development

Abstract

During larval development of Salamandra salamandra salamandra chromatophores organize to form the definitive pigment pattern constituted by a black background with yellow patches that are characterized by epidermal xanthophores and dermal iridophores. Simultaneously the dermis undergoes remodeling from the larval stage to that typical of the adult. In the present study we ultrastucturally and immunocytochemically examined skin fragments of S. s. salamandra larvae and juveniles in order to investigate the modalities of xanthophore migration and differentiation in the context of dermal remodeling from the larval to adult stage. Semithin and thin sections showed that the dermis in newly born larvae consists of a compact connective tissue (basement lamella), to which fibroblasts and xanthophores adhere, and of a loose deep collagen layer. As larval development proceeds, fibroblasts and xanthophores invade the basement lamella, skin glands develop and the adult dermis forms. At metamorphosis, xanthophores reach the epidermis crossing through the basal lamina. We examined immunocytochemically the expression of signal molecules, such as fibronectin, vitronectin, beta1-integrin, chondroitin sulfate, E-cadherin, N-cadherin and plasminogen activator, which are known to be involved in regulating morphogenetic events. Their role in dermal remodeling and in pigment pattern formation is discussed.

Coordinated Regulation of Chromatophore Differentiation and Melanogenesis during the Ontogeny of Skin Pigmentation of Solea senegalensis (Kaup, 1858)

“…Similarly, the patches of xanthophores and leucophores observed at 2 dph in Senegalese sole where located at specific points of the dorsal and anal fins and they seemed to function as reference points for the migration of melanophores to the fins at pro-metamorphosis (Fig. 2A–F) [77]. From 33 to 35 dph, a decrease in the proportion of xanthophores versus melanophores was found, with morphological evidences of disintegrating xanthophores (Fig.…”

Dual appearance of xanthophores, and ontogenetic changes in other pigment cells during early development of Japanese flounder Paralichthys olivaceus

“…On the other hand, the depths at which xanthophores on the blind side (early-appearing population) were present were similar to those of the larval-type melanophores ( Table 1). Ontogenic changes in the depths of the xanthophores on the blind side were probably due to skin thickening, as discussed for larval-type melanophores, and/ or migration of early-appearing xanthophores, as observed in salamander larvae [8]. With regard to the depth and time of appearance, melanophores and xanthophores may have common features; the early-appearing population is located deep in the skin, whereas the late-appearing population is found closer to the surface of the skin.…”

Specific features of the melanophore system in different color morphs of larvae of the common toad (Bufo bufo L.)

“…There are published data on the capacity for migrating of sev eral types of chromatophores in amphibians, describ ing the migration of pigment cells between the dermal and epidermal skin layers (Yasutomi, 1987;Yasutomi and Yamada, 1998). In larvae of the salamander, migration of xanthophores through vertical canals in the basal membrane is shown (Pederzoli et al, 2003). During metamorphosis, migration of epidermal mel anophores to the dermis in R. japonica takes place (Yasutomi, 1987).…”