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

A new genus of orthocladiine Chironomidae. Botryocladius (type species B. grapeth sp.n. from eastern Australia) is described and illustrated in all life 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 and B. freemani), one from ephemeral streams in Australia (B. petrophilus) and four from Patagonian Argentina and Chile (B. edwardsi, B. glacialis, B. mapuche and B. tronador). All Australian species are known from at least pupal exuviae, most from adult males and several from larvae. In contrast, only B. edwardsi amongst Neotropical species is known from the adult male; all 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 formally undescribed taxa from Australia. The genus evidently demonstrates a vicariant distribution with at least two sister-group relationships between South 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.