LAUSR

Alexander Evgenievich Balakirev, Alexei Vladimirovich Abramov, and Viatcheslav Vladimirovich Rozhnov (2017) The phylogeographic pattern of Maxomys surifer across most of its geographic range was investigated based on existing sequencing from GenBank and new original data from Vietnam to evaluate its natural subdivision and taxonomic structure in Indochina and neighboring regions. Seven major phylogenetic clusters/groups are apparent on the cytochrome b (Cyt b) and cytochrome с oxydase subunit 1 gene (COI) trees, corresponding to geographical subpopulations of the species. Among them, distinct position of most divergent, clade Msur7 is also supported by analyses of nuclear (IRBP) gene. The taxonomic implication of these findings is tested by comparison of morphological features of this Northern (labeled by Msur7) and Southern Vietnamese populations widely distributed over the Indochina labeled by Msur3 mtDNA genetic marker. Direct comparisons of skulls measurements and multivariate analyses performed for these southern and northern populations showed that latter specimens are distinctive in being signi cantly larger in a number of cranial characters, with diagnostically smaller teeth relative to M. surifer from southern Vietnam, bearing also some traits in its external appearance, like relative tail length and coloration pattern. The pattern of genetic and cranial variation in M. surifer revealed in the present study suggests the existence of distinct genetic lineages and suspected longitudinal isolation, corresponding to morphologically distinctive forms. It is evident that at least some of these lineages merit subspecific status. We provide a taxonomical description elevating the northern Vietnamese populations to a new subspecies M. s. tonkinensis subsp. nov. We discuss the taxonomic implications, tentative range, and appropriate synonyms for all main genetic lineages over the range of M. surifer in the Sundaic region.