Four new earthworm species of the genus Amynthas (Megascolecidae: Oligochaeta) from southwestern Taiwan with re-description of Amynthas tungpuensis Tsai, Shen and Tsai, 1999

摘要

This study describes four new species of earthworms belonging to the genus Amynthas (Megascolecidae: Oligochaeta) from southwestern Taiwan. They are Amynthas quadriorbis sp. nov., Amynthas douliouensis sp. nov., Amynthas tsou sp. nov. and Amynthas dinghuensis sp. nov. The former three species are sexthecate with three pairs of spermathecal pores in 6/7-8/9 whereas A. dinghuensis is a small, octothecate earthworm with four pairs of spermathecal pores in 5/6-8/9. Amynthas quadriorbis and A. douliouensis were found in the foothills at elevations < 250 m near Douliou, Yunlin, whereas A. tsou and A. dinghuensis were from elevations of 1400-1664 m in the Alishan area, Chiayi. Amynthas quadriorbis has four large genital papillae in the male pore region. Amynthas douliouensis has paired genital papillae in presetal VIII-X and simple male pore structure. Amynthas tsou has paired genital papillae in presetal VIII-IX and male porophore with or without an anterior, posteromedial, or one anteromedial and one posteromedial papillae. Amynthas dinghuensis has two pairs of genital papillae medial to male porophores in postsetal XVII and presetal XIX. In addition, re-description of Amynthas tungpuensis, an endemic earthworm widely distributed in western Taiwan, is given. DNA barcodes (a 658-base-pair section of the mitochondrial cytochrome c oxidase subunit I gene) of the four new species and of A. tungpuensis are also reported.