49 INTRODUCTION A number of phylogenies for the Anatidae have been proposed (e.g., Delacour & Mayr 1945; Del Hoyo et al. 1992; Livezey 1986, 1997) and a consensus appears to be emerging (e.g., Donne- Goussé et al. 2002; Gonzalez et al. 2009; Bulgarella et al. 2010), yet uncertainty remains about the ainities of some monotypic genera. The endangered blue duck (Hymenolaimus malacorhynchos) of New Zealand, an endemic riverine specialist (Marchant & Higgins 1990; Robertson et al. 2007), is one such taxa of uncertain placement. Hymenolaimus inhabits mountain rivers and shares ecological adaptations in common with other river ducks (e.g., torrent duck Merganeta armata and Salavadori’s duck Salvadornia waigiuensis), which has contributed to speculation on the shared phylogenetic ainities of these species (see Kear 2005). Delacour and Mayr (1945), however, refuted any suggestion that blue ducks were similar to either Merganeta or Salvadornia. Studies of morphology, behaviour and DNA have consistently placed Hymenolaimus in the Family Anatidae (Gill et al. 2010). However, the taxon has variously been suggested to be: (i) an aberrant Anas species in the dabbling ducks (Tribe Anatini: sensu Delacour & Mayr 1945); (ii) an ancient Anatini with no close relatives due to ainities with both the perching ducks (Tribe Cairinini) and Notornis, 2012, Vol. 59: 49-59 0029-4470 © The Ornithological Society of New Zealand, Inc. Received 9 Sep 2011; accepted 14 May 2012 *Correspondence: bruce.robertson@otago.ac.nz Phylogenetic afinities of the New Zealand blue duck (Hymenolaimus malacorhynchos) BRUCE C. ROBERTSON* Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand SHARYN J. GOLDSTIEN School of Biological Sciences, University of Canterbury, PB 4800, Christchurch, New Zealand Abstract We investigate the phylogenetic ainites of the New Zealand blue duck (Hymenolaimus malacorhynchos), a riverine specialist of uncertain relationships, using 2613 bp of DNA sequence data from 3 mitochondrial genes. Hymenolaimus has variously been considered an aberrant Anas species, or an ancient taxa in the tribe Anatini. Presently, it is placed in a highly-derived clade (Tribe Merganetini) with the shelducks. Our indings show that Hymenolaimus forms a monophyletic clade, and does not it within any of the other duck tribes around the world. Our study also conirms convergent evolution among duck species that inhabit fast lowing rivers. Robertson, B.C.; Goldstien, S.J. 2012. Phylogenetic ainities of the New Zealand blue duck (Hymenolaimus malacorhynchos). Notornis 59 (1&2): 49-59. Keywords blue duck; Anseriformes; cytochrome b gene; control region gene; ND2 gene; mitochondrial DNA; phylogenetics