title: Mountain colonisation, miniaturisation and ecological evolution in a radiation of direct-developing New Guinea Frogs (Choerophryne, Microhylidae).
abstract: OBJECTIVE
  Mountain ranges in the tropics are characterised by high levels of localised endemism, often-aberrant evolutionary trajectories, and some of the world's most diverse regional biotas. Here we investigate the evolution of montane endemism, ecology and body size in a clade of direct-developing frogs (Choerophryne,Microhylidae) from New Guinea.
  
  
  METHODS
  Phylogenetic relationships were estimated from a mitochondrial molecular dataset using Bayesian and maximum likelihood approaches. Ancestral state reconstruction was used to infer the evolution of elevational distribution, ecology (indexed by male calling height), and body size, and phylogenetically corrected regression was employed to examine the relationships between these three traits.
  
  
  RESULTS
  We obtained strong support for a monophyletic lineage comprising the majority of taxa sampled. Within this clade we identified one subclade that appears to have diversified primarily in montane habitats of the Central Cordillera (>1,000 m a.s.l.), with subsequent dispersal to isolated North Papuan Mountains. A second subclade (characterised by moderately to very elongated snouts) appears to have diversified primarily in hill forests (<1,000 m a.s.l.), with inferred independent upwards colonisations of isolated montane habitats, especially in isolated North Papuan Mountains. We found no clear relationship between extremely small body size (adult SVL less than 15 mm) and elevation, but a stronger relationship with ecology-smaller species tend to be more terrestrial.
  
  
  CONCLUSIONS
  Orogeny and climatic oscillations have interacted to generate high montane biodiversity in New Guinea via both localised diversification within montane habitats (centric endemism) and periodic dispersal across lowland regions (eccentric endemism). The correlation between extreme miniaturisation and terrestrial habits reflects a general trend in frogs, suggesting that ecological or physiological constraints limit niche usage by miniaturised frogs, even in extremely wet environments such as tropical mountains.
authors.affiliation: Division of Ecology and Evolution, Research School of Biology & Centre for Biodiversity Analysis, Australian National University , Canberra , Australian Capital Territory , Australia.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Oliver
authors.affiliation: School of Biological Sciences, The University of Adelaide , Adelaide , South Australia , Australia.
authors.forename: Amy
authors.initials: A
authors.lastname: Iannella
authors.affiliation: South Australian Museum , Adelaide , South Australia , Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Richards
authors.affiliation: South Australian Museum, Adelaide, South Australia, Australia; School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia.
authors.forename: Michael S Y
authors.initials: MS
authors.lastname: Lee
keywords: Central Cordillera; Endemism; Montane cradle; Montane museum; North Papuan Mountains; Terrestrial