Review of the Flat Back Millipede Genus Yuennanina Attems, 1936 (Polydesmida: Paradoxosomatidae), with the Description of a New Species from Thailand

The millipede genus Yuennanina Attems, 1936 has been known so far only from Yunnan Province, southwestern China. Currently, it comprises three species: Y. ceratogaster Attems, 1936, Y. aceratogaster Zhang & Li, 1977, and Y. petalolobodes Chang & Zhang, 1989. Herein, we describe Y. sirindhornae sp. nov., from Huai Nam Dang, Chiang Mai Province, northern Thailand, representing the first formal record of this genus not only from Thailand, but also from entire Southeast Asia. The new species is characterized by its unique gonopodal solenophore the shape of which resembles a young fern frond with fimbriate edges. A detailed redescription of the type species, Y. ceratogaster, is provided based on a revision of type material. An updated identification key to all four presently known Yuennanina species is also provided.