Fig. 3

Morphological characteristics of poison glands of type COM, typical of dorsal warts. (a) Part of a syncytium (syn) with peripheral nuclei (n) and a large amount of heterogeneous poison granules (g). my, myoepithelial layer, v, blood vessel. (b-d) In all studied species, the poison granules show internal subunits. (e) Poison granules (gr) with smooth surface immersed in the syncytial cytoplasm matrix (syn). (f) Syncytial granules (gr) with rough surface and different degrees of compaction, and lamellae with small granules inside (arrowheads). Insert: granules (gr) with compact periphery and internal subunits. (g) Ultrathin section evidencing heterogeneity of the poison granules (gr). n, nucleus; syn, syncytial cytoplasm. (h and i) Syncytial organelles amongst poison granules (gr). Notice the fusion between two poison granules (arrow). gol, Golgi apparatus; rer, rough endoplasmic reticulum; *, mitochondrium. Species: Rhinella icterica (a, e), Rhinella schneideri (b, f insert), Rhinella marina (c, f, g) Rhinella jimi (d, h, i). Histological sections stained with toluidine blue-fuchsine (a-d). SEM cryofractures (e-f). TEM (g-i)