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学、组织化学技术结合偏振光显微镜，对苇叶蟾亚科（Scinaxnae）2个属的10种树蛙物种的皮肤被膜（integuments）展开观察研究，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）。 所有受试物种的皮肤被膜均具备无尾目动物皮肤的基本结构。研究发现，外分泌腺的分泌部（如浆液性局部分泌腺与顶浆分泌腺）均局限于海绵状真皮层内。顶浆分泌型腺体的异质性分泌物质中伴随脂质成分。部分物种的腹外侧皮肤被膜中存在此类顶浆分泌腺的集群结构。所有受试雨蛙科（Hylidae）物种均检测到黑素细胞（melanophores）；而通过偏振光显微镜检出的虹彩细胞（iridophores）的存在情况则因物种不同存在差异。 埃伯特-卡申科层（Eberth-Katschenko layer）可在两个属物种的背部皮肤被膜中观测到，但仅在O. albicans、O. angrensis、O. flavoguttata、O. perpusilla及O. v-signata的腹部皮肤被膜中存在。尽管所有树蛙的皮肤被膜均具有相同的基础结构，部分特征呈现属特异性，但仅依靠这些特征不足以区分这两个属。