The geography of speciation in dasyurid marsupials

Aim: To determine the effects of competition and divergence time on morphological dissimilarity and geographical range overlap between dasyurid species at both regional and local scales. Our hypothesis is that speciation in this group has been largely allopatric at regional scale, but involved morphological divergence at local scale through sympatric character displacement. Location: Australia, New Guinea and surrounding islands. Taxon: Dasyurid (Dasyuridae) marsupials, 67 species. Methods: Geographical range overlap was quantified using polygons representing the outer limits of species distributions. Local‐scale range overlap was quantified as the degree of co‐occurrence of two taxa across a set of ecological survey plots representing 83 sampled communities. Phylogenies were generated using a novel DNA dataset, with divergence times estimated via total‐evidence dating incorporating fossils. Morphological divergence was determined using body mass and lower molar row length as p...研究目标：明确竞争与分化时间在区域和局域尺度下，对袋鼬科（Dasyuridae）物种种间形态差异与地理分布重叠的影响。本研究提出假说：该类群的物种形成在区域尺度上以异域成种为主，而在局域尺度上则通过同域性状置换实现形态分化。 研究区域：澳大利亚、新几内亚及其周边岛屿。 研究类群：袋鼬科（Dasyuridae）有袋类动物，共计67个物种。 研究方法：以代表物种种群分布外围边界的多边形量化地理分布重叠程度；局域尺度的分布重叠则以两类群在83个采样生态调查样地中的共存度进行量化。利用全新的DNA数据集构建系统发育树，并通过整合化石证据的总证据定年法估算分化时间。以体重和下臼齿列长度作为指标测定形态分化程度。