Evidence from Australian mesic zone dung beetles supports their Gondwanan origin and Mesozoic diversification of the Scarabaeinae. Supplemental Material

The
evolution of dung beetles remains contentious with two hypotheses reflecting
Cretaceous and Paleo­gene origins driven by different methods. We explore
biogeographic evidence and phylogeographic origins against vicariance and
dispersal scenarios that attribute to the four elements of the Australian fauna
using a multi-gene approach. Maximum-likelihood and Bayesian analyses supported
the Australasian clade, com­posed of almost all Australian, New Caledonian and
New Zealand endemic genera (to the exclusion of Bo­letoscapter). Two
Australian lineages with east-west splits and few lineages with restricted,
non-overlapping distrbution were identified, and biogeography models provided
evidence that vicariance and founder event speciation are important processes
in the diversification of Australasian scarabaeines. Our phylogenetic results
are largely congruent with a mid-Cretaceous origin of the Australasian clade,
the tectonic history of Gondwanaland and climatic history of the Australian
continent, and provide compelling evidence that Australian dung beetles are a
relictual fauna whose history is linked to mesic zone fragmentation.

蜣螂的演化历程迄今仍存在争议，学界基于不同研究方法提出了白垩纪起源与古近纪起源两种假说。本研究采用多基因分析方法，围绕隔离分化与扩散两种生物地理情景，针对构成澳大利亚动物区系四大组分的类群，探究其生物地理学证据与系统生物地理学起源。最大似然法与贝叶斯分析均支持澳大拉西亚演化支的单系性，该演化支几乎涵盖了澳大利亚、新喀里多尼亚与新西兰的所有特有属（除外Boletoscapter属）。研究鉴定出两支呈现东西分化格局的澳大利亚演化支，以及少数分布范围受限且互不重叠的演化支；生物地理学模型结果显示，隔离分化与奠基者物种形成是澳大拉西亚蜣螂亚科类群物种分化的重要过程。本研究的系统发育结果与澳大拉西亚演化支的白垩纪中期起源时间、冈瓦纳大陆构造演化历史以及澳大利亚大陆的气候变迁历史基本吻合，同时有力证明澳大利亚蜣螂属于孑遗动物区系，其演化历史与湿润带的破碎化过程紧密相关。