Synonymy of the water mite families malgasacaridae and zelandothyadidae (Acari: Hydrachnidia) reveals an interesting disjunct distribution in the southern hemisphere

Abstract

A new species of Zelandothyas, Z. balloti, is described from South Island, New Zealand. The deutonymph and larva of Zelandothyas diamphida Cook, 1983 are described for the first time. The deutonymph of Malgasacarus rarus Tuzovskij et al., 2008 is redescribed. The family Malgasacaridae Tuzovskij, Gerecke & Goldschmidt, 2008 is synonymized with Zelandothyadidae Cook, 1983 and Malgasacarus Tuzovskij et al., 2008 is transferred to the subfamily Zelandothyadinae. Thus redefined, the family Zelandothyadidae shows an interesting disjunction in the Southern Hemisphere. Here, it is considered a family incertae sedis, provisionally comprising the monophyletic Zelandothyadinae and the enigmatic Australiothyadinae Cook, 1986. Zelandothyadidae are unusual in combining character states previously considered diagnostic for either Eylaoidea or Hydryphantoidea.