title: A remarkable case of micro-endemism in Laonastes aenigmamus (Diatomyidae, Rodentia) revealed by nuclear and mitochondrial DNA sequence data.
abstract: L. aenigmamus is endemic to the limestone formations of the Khammuan Province (Lao PDR), and is strongly specialized ecologically. From the survey of 137 individuals collected from 38 localities, we studied the phylogeography of this species using one mitochondrial (Cyt b) and two nuclear genes (BFIBR and GHR). Cyt b analyses reveal a strong mtDNA phylogeographical structure: 8 major geographical clades differing by 5-14% sequence divergence were identified, most of them corresponding to distinct karst areas. Nuclear markers display congruent results but with a less genetic structuring. Together, the data strongly suggest an inland insular model for Laonastes population structure. With 8 to 16 evolutionary significant units in a small area (about 200×50 km) this represents an exceptional example of micro-endemism. Our results suggest that L. aenigmamus may represent a complex of species and/or sub-species. The common ancestor of all Laonastes may have been widely distributed within the limestone formations of the Khammuan Province at the end of Miocene/beginning of the Pliocene. Parallel events of karst fragmentation and population isolation would have occurred during the Pleistocene or/and the end of the Pliocene. The limited gene flow detected between populations from different karst blocks restrains the likelihood of survival of Laonastes. This work increases the necessity for a strict protection of this rare animal and its habitat and provides exclusive information, essential to the organization of its protection.
authors.affiliation: UMR CNRS 7205, Département Systématique et Evolution, Muséum National d'Histoire Naturelle, Paris, France. vnicolas@mnhn.fr
authors.forename: Violaine
authors.initials: V
authors.lastname: Nicolas
authors.forename: Vincent
authors.initials: V
authors.lastname: Herbreteau
authors.forename: Arnaud
authors.initials: A
authors.lastname: Couloux
authors.forename: Kham
authors.initials: K
authors.lastname: Keovichit
authors.forename: Bounneuang
authors.initials: B
authors.lastname: Douangboupha
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Hugot
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D008928:Mitochondria / Q000235:genetics; D012377:Rodentia / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial