Botryocladius gen.n.: a new transantarctic genus of orthocladiine midge (Diptera : Chironomidae)

A new genus of orthocladiine Chironomidae. Botryocladius (type species B. g rapeth sp.n. from eastern Australia) is described and illustrated in all li fe history stages. All thirteen included species are described as new, six from eastern Australia (B. grapeth, B. brindabella, B, mdfrc, B. collessi, B. tasmania, B. australoalpinus), two from Western Australia (B. bibulmun a nd B. freemani), one from ephemeral streams in Australia (B. petrophilus) a nd four from Patagonian Argentina and Chile (B. edwardsi, B. glacialis, B. mapuche and B. tronador). All Australian species are known from at least pu pal exuviae, most from adult males and several from larvae. In contrast, on ly B. edwardsi amongst Neotropical species is known from the adult male; al l others are described from pupal exuviae. The immature stages are lotic in Australian permanent and temporary streams and Patagonian glacial streams and rivers, and lentic in Neotropical glacial-fed and Australian subalpine lakes. Botryocladius appears to belong with a grouping centred on two forma lly undescribed taxa from Australia. The genus evidently demonstrates a vic ariant distribution with at least two sister-group relationships between So uth American and Australian taxa, providing a minimum dating for the clade of 38 Ma., with apparent absence from New Zealand indicating a maximum date of 80 Ma.