Comparative analysis of the integument of different tree frog species from Ololygon and Scinax genera (Anura: Hylidae)

ABSTRACT The integuments of ten treefrog species of two genera from Scinaxnae - O. angrensis (Lutz, 1973), O. flavoguttata (Lutz & Lutz, 1939), O. humilis (Lutz & Lutz, 1954), O. perpusilla (Lutz & Lutz, 1939), O. v-signata (Lutz, 1968), Scinax hayii (Barbour, 1909), S. similis (Cochran, 1952), O. trapicheroi (Lutz & Lutz, 1954) and S. x-signatus (Spix, 1824) - were investigated using conventional and histochemical techniques of light microscopy, and polarized light microscopy. All integuments showed the basic structure of the anuran integument. Moreover, the secretory portions of exocrine glands, such as serous merocrine and apocrine glands, were found to be restricted to the spongious dermis. Lipid content occurred together with the heterogeneous secretory material of the glands with an apocrine secretion mechanism. In addition, clusters of these apocrine glands were present in the ventrolateral integument of some species. Melanophores were also visualized in all examined hylids. However, the occurrence of iridophores, detected through polarized light microscopy, varied according to the species. The Eberth-Katschenko layer occurred in the dorsal integument from both genera, but it was only present in the ventral integument of O. albicans, O. angrensis, O. flavoguttata, O. perpusilla and O. v-signata. Although the integument of all treefrogs showed the same basic structure, some characteristics were genus-specific; however, these features alone may not be used to distinguish both genera.

摘要 本研究采用光学显微镜常规组织化学技术与偏光显微镜技术，对树蛙亚科（Scinaxinae）两属共10个物种的皮肤组织开展了观察分析，涉及物种包括：O. angrensis（Lutz, 1973）、O. flavoguttata（Lutz & Lutz, 1939）、O. humilis（Lutz & Lutz, 1954）、O. perpusilla（Lutz & Lutz, 1939）、O. v-signata（Lutz, 1968）、Scinax hayii（Barbour, 1909）、S. similis（Cochran, 1952）、O. trapicheroi（Lutz & Lutz, 1954）以及S. x-signatus（Spix, 1824）。所有受试皮肤组织均呈现无尾类皮肤的基本结构。此外，外分泌腺的分泌部（如浆液性局泌腺与顶泌腺）均仅分布于海绵状真皮层中。采用顶泌分泌机制的腺体，其分泌产物中混杂有脂质成分。部分物种的腹外侧皮肤组织中还存在此类顶泌腺的集群结构。所有受试雨蛙类物种的皮肤中均可见黑素细胞。而通过偏光显微镜检测到的虹彩细胞，则存在物种特异性差异。埃伯特-卡申科层（Eberth-Katschenko layer）仅见于两属物种的背部皮肤，但仅在O. albicans、O. angrensis、O. flavoguttata、O. perpusilla与O. v-signata的腹部皮肤中存在。尽管所有树蛙的皮肤均具有相同的基本结构，部分特征呈现属特异性，但仅凭这些特征不足以区分这两个属。