Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Ann Anat
2023 Aug 01;249:152097. doi: 10.1016/j.aanat.2023.152097.
Show Gene links
Show Anatomy links
Histological changes of the skin during postembryonic development of the crested newt Triturus ivanbureschi (Urodela, Salamandridae).
Ajduković M
,
Ukropina M
,
Cvijanović M
,
Vučić T
,
Ivanović A
.
???displayArticle.abstract???
BACKGROUND: Amphibian skin has been studied for many decades, especially the metamorphic changes in the skin of frogs. Less attention has been paid to salamander skin. Here, we describe changes in the skin structure during postembryonic development in a salamandrid species, the Balkan crested newt Triturus ivanbureschi.
METHOD: Using traditional histological techniques we examined the skin in the trunk region of three premetamorphic larval stages (hatchling, mid larval and late larval) and two postmetamorphic stages (juvenile, just after metamorphosis, and adult).
RESULTS: In larval stages, skin consists only of the epidermis, which gradually develops from the single epithelial cell layer in hatchlings, to a stratified epidermis with gland nests and characteristic Leydig cells at the late larval stage. During metamorphosis, Leydig cells disappear, and the dermal layer develops. In postmetamorphic stages, skin is differentiated on stratified epidermis and the dermis with well-developed glands. Three types of glands were observed in the skin of the postmetamorphic stages: mucous, granular and mixed. Gland composition appears to be stage- and sex-specific, with juveniles and adult female being more similar to each other. In juveniles and adult female, there are a similar proportion of glands in both dorsal and ventralskin, whereas in adult male granular glands dominated the dorsal skin, while mixed glands dominated the ventralskin.
CONCLUSION: Our results provide a baseline for future comparative research of skin anatomy in salamanders.
Fig. 1. Detailed description where the skin samples were taken from dorsal (A) and ventral (B) side of the juveniles and adults. Micrograph (C) is showing how morphometric measurements of the epidermis (e) and dermis (d) were taken.
Fig. 2. Closely adjacent skin sections of postmetamorphic Triturus ivanbureschi stained with AB-PAS (A, B) and BPB (C, D). The staining outcomes are marked by symbols: AB- (△), AB+ (▲), PAS- (☆), PAS+ (★), BPB- (○), BPB+ (●). Comparison reveals that (i) AB-positive products (▲) are at the same time negative for BPB (○), hence they are acid mucins; (ii) PAS-positive products (★) are at the same time positive for BPB (●), therefore they are glycosylated proteins; (iii) both AB- and PAS-negative products (△, ☆) are positive for BPB (●), i.e. they are proteins. Epidermis (e), dermis (d), basement membrane (bm), mucous gland (mg), granular gland (gg), mixed gland (mixg). Original magnification 20 × , bar= 100 µm.
Fig. 3. Histological organization of the skin in premetamorphic Triturus ivanbureschi stained with AB-PAS. In hatchlings, stage 42 (A), mid larval stage, stage 47 (B), and late larval stage, stage 62 (C) the skin is composed solely of epidermis (e), which is covered with acid mucus (am). Melanophores (m) are positioned within discontinuous layer underlining the epidermis in all investigated stages. Skin consists of single layer of flattened cells in hatchlings, and two-cell high epidermis with rare gland nests (gn) at mid larval stage. At the late larval stage numerous voluminous Leydig cells (Lc) are evident between epithelial cells, which are occasionally organized into gland nests. Original magnification 40 × , bar = 50 µm.
Fig. 4. Histological organization of the dorsal and ventral skin in postmetamorphic Triturus ivanbureschi stained with AB-PAS. In juveniles (A, D), and both adult female (B, E), and male (C, F) skin is composed of epidermis (e) and dermis (d) which is composed of connective tissue that houses the discontinuous subepidermal layer of melanophores (m). The epidermis is composed of stratified squamous non-keratinized epithelium and is not covered with acid mucus. Basement membrane (bm) is visible between epidermis and dermis in adult individuals only. Three types of skin glands are present within the dermis in postmetamorphic animals: mucous gland (mg), granular gland (gg) and mixed gland (mixg). Distinct vacuolated cells (vc) are more often observed within glands positioned in ventral skin. Original magnification 20 × , bar= 100 µm.
Fig. 5. Proportion of epidermis and dermis, expressed as mean percentages of total skin thickness, in postmetamorphic stages (juvenile, female and male). Total N are reported in Table 4.
Fig. 6. Frequency distribution of the three gland types in the dorsal and ventral skin at different postmetamorphic stages (juveniles, female, male), expressed as mean percentage of a particular gland type on the total number of glands.
