Distribution and speciation in marine intertidal tardigrades: testing the roles of climatic and geographical isolation

摘要: Aim  To analyse the importance of climatic and geographical isolation in determining patterns speciation distribution species within tardigrade genus Echiniscoides. Location  Marine intertidal zone, globally. Methods  DNA was extracted from 465 individual tardigrades 48 localities world-wide. The were divided into clusters using several distance-based criteria. phylogeny these estimated with Bayesian analyses. relationships between genetic distance substrate, climate, tested a new improved Mantel test which incorporates phylogenetic uncertainties by analysing raw tree data instead averaged tree. Results  Approximately 40 clusters, each probably corresponding to species, recovered analysis; number fluctuated depending on criterion used for cluster delimitation. Each had limited temperature range all confined single oceans under realistic criteria Apart tropical cluster, occurred only one hemisphere. Occurrence different substrata not correlated clusters. Both climate distance; however, correlation disappeared when non-independence controlled for. Main conclusions  Echiniscoides is distance. Distance does appear be major factor influencing this genus, but ecological along gradient appears important.