Species invasions represent a significant dimension of global change yet the dynamics of invasions remain poorly understood and are considered rather unpredictable. We explored interannual dynamics of the invasion process in the Eurasian collared dove () and tested whether the advance of the invasion front of the species in North America relates to centrality (versus peripherality) within its estimated fundamental ecological niche. We used ecological niche modelling approaches to estimate the dimensions of the fundamental ecological niche on the Old World distribution of the species, and then transferred that model to the New World as measures of centrality versus peripherality within the niche for the species. Although our hypothesis was that the invasion front would advance faster over more favourable (i.e. more central) conditions, the reverse was the case: the invasion expanded faster in areas presenting less favourable (i.e. more peripheral) conditions for the species as it advanced across North America. This result offers a first view of a predictive approach to the dynamics of species' invasions, and thereby has relevant implications for the management of invasive species, as such a predictive understanding would allow better anticipation of coming steps and advances in the progress of invasions, important to designing and guiding effective remediation and mitigation efforts.

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The idea of ring species has been viewed as a demonstration of the potential for species‐level differentiation produced by isolation by distance in otherwise continuous populations. Although the concept is attractive, the list of empirical examples has narrowed significantly as detailed studies have been carried out. One of the few examples still cited among birds is the warbler species complex Phylloscopus trochiloides, which comprises P. trochiloides sensu stricto, P. plumbeitarsus, and P. nitidus. The ring comprises a series of populations surrounding the Tibetan Plateau in which a species‐level break is apparent at the north end of the ring. Although recent theoretical treatments have indicated that such differentiation is possible in theory, recent genomic analyses indicated multiple differentiated populations around the ring unlikely to have resulted from isolation by distance. Here, we complement the genomic studies to date with paleodistributional projections of ecological niche models that provide further evidence for multiple, isolated refugia around the ring during and since the Late Pleistocene. As such, this group should not be interpreted as exemplifying an isolation‐by‐distance mechanism of speciation, and should no longer be considered as a ring species: genomic and geographic evidence coincide in indicating that its differentiation took place in allopatry.

An integrative taxonomic analysis of the Ptychozoon lionotum group across its range in Indochina and Sundaland recovers P. lionotum sensu lato Annandale, 1905 as paraphyletic with respect to P. popaense Grismer, Wood, Thura, Grismer, Brown, & Stuart, 2018a and composed of four allopatric, genetically divergent, ND2 mitochondrial lineages. Multivariate and univariate analyses of continuous and discrete morphological and color pattern characters statistically and discretely diagnose each lineage from one another and together, with maximum likelihood and Bayesian inference analyses, provide the foundation for the recognition of each lineage as a new species—hypotheses corroborated with a Generalized Mixed Yule Coalescent species delimitation analysis. Ptychozoon cicakterbang sp. nov. ranges throughout Peninsular Malaysia to Pulau Natuna Besar, Indonesia; P. kabkaebin sp. nov. is endemic to northern and central Laos; and P. tokehos sp. nov. ranges from southern Thailand south of the Isthmus of Kra northward to Chiang Mai, fringing the Chao Phraya Basin and ranging southward through Cambodia to southern Vietnam. Ptychozoon lionotum sensu stricto ranges from northwestern Laos through southern Myanmar to eastern India. The phylogeographic structure within each species varies considerably with P. lionotum s.s. showing no genetic divergence across its 1,100 km range compared to P. cicakterbang sp. nov. showing upwards of 8.2% sequence divergence between syntopic individuals. Significant phylogeographic structure exists within P. tokehos sp. nov. and increased sampling throughout Thailand may require additional taxonomic changes within this species.

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