title: Different morphologic formation patterns of dark patches in the black-spotted frog (Pelophylax nigromaculata) and the Asiatic toad (Bufo gargarizans).
abstract: The black-spotted frog (Pelophylax nigromaculata) and Asiatic toad (Bufo gargarizans), two relatively distantly related species, live in different habitats with different adaptive dark patches. To explain the formation of dark patches, the distribution patterns of melanin granules were examined with light microscopy and transmission electron microscopy. Melanin granules were produced and gathered into the "cap" structures on top of the nuclei in most epidermal cells. The "cap" structures may play a role in forming the dorsal dark patches coupled with three-layer melanophores, which can give rise to three layers of interconnected melanin networks in the dorsal dermis in P. nigromaculata. Epidermal melanocytes are rare and do not have a definitive role in forming dorsal dark patches in either P. nigromaculata or B. gargarizans. In B. gargarizans, the dermal melanophores only give rise to a single-layered melanin network, which hardly results in dark patches in the dorsal skin. However, the dermal melanophores migrate twice and form into pseudostratified networks, leading to dark patch formation in the ventral skin in B. gargarizans. The melanin granules precisely coregulate dark patches in the dermis and/or epidermis in P. nigromaculata and B. gargarizans. The dark patch formation depends on melanin granules in the epidermis or/and dermis in P. nigromaculata and B. gargarizans.
authors: Department of Genetics and Developmental Biology, Southeast University Medical School, Nanjing, 210009, Jiangsu, China. ganguangm@seu.edu.cn.|Medical School, Southeast University, Dingjiaqiao, Gu Lou District, Nanjing, 210009, China. ganguangm@seu.edu.cn.
authors: Gan
authors: G
authors: Guangming
authors: Department of Genetics and Developmental Biology, Southeast University Medical School, Nanjing, 210009, Jiangsu, China.
authors: Zhao
authors: Z
authors: Tao
authors: Department of Genetics and Developmental Biology, Southeast University Medical School, Nanjing, 210009, Jiangsu, China.
authors: Li
authors: L
authors: Chao
authors: Department of Genetics and Developmental Biology, Southeast University Medical School, Nanjing, 210009, Jiangsu, China.
authors: Zhao
authors: Z
authors: Moyan
mesh_terms: D000818:Animals; D001001:Anura / Q000033:anatomy & histology*; D002467:Cell Nucleus / Q000378:metabolism; D020405:Dermis / Q000166:cytology / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D008543:Melanins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D008547:Melanophores / Q000378:metabolism / Q000648:ultrastructure; D008853:Microscopy; D046529:Microscopy, Electron, Transmission
chemical_list: D008543:Melanins
keywords: Bufo gargarizans; Color change; Dark patch; Pelophylax nigromaculata; “Cap” structure