title: Genetic divergence and diversity in the Mona and Virgin Islands Boas, Chilabothrus monensis (Epicrates monensis) (Serpentes: Boidae), West Indian snakes of special conservation concern.
abstract: Habitat fragmentation reduces the extent and connectivity of suitable habitats, and can lead to changes in population genetic structure. Limited gene flow among isolated demes can result in increased genetic divergence among populations, and decreased genetic diversity within demes. We assessed patterns of genetic variation in the Caribbean boa Chilabothrus monensis (Epicrates monensis) using two mitochondrial and seven nuclear markers, and relying on the largest number of specimens of these snakes examined to date. Two disjunct subspecies of C. monensis are recognized: the threatened C. m. monensis, endemic to Mona Island, and the rare and endangered C. m. granti, which occurs on various islands of the Puerto Rican Bank. Mitochondrial and nuclear markers revealed unambiguous genetic differences between the taxa, and coalescent species delimitation methods indicated that these snakes likely are different evolutionary lineages, which we recognize at the species level, C. monensis and C. granti. All examined loci in C. monensis (sensu stricto) are monomorphic, which may indicate a recent bottleneck event. Each population of C. granti exclusively contains private mtDNA haplotypes, but five of the seven nuclear genes assayed are monomorphic, and nucleotide diversity is low in the two remaining markers. The faster pace of evolution of mtDNA possibly reflects the present-day isolation of populations of C. granti, whereas the slower substitution rate of nuDNA may instead mirror the relatively recent episodes of connectivity among the populations facilitated by the lower sea level during the Pleistocene. The small degree of overall genetic variation in C. granti suggests that demes of this snake could be managed as a single unit, a practice that would significantly increase their effective population size.
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, USA. Electronic address: javier.rodriguez@unlv.edu.
authors.forename: Javier A
authors.initials: JA
authors.lastname: Rodríguez-Robles
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, USA. Electronic address: tjezkova@email.arizona.edu.
authors.forename: Tereza
authors.initials: T
authors.lastname: Jezkova
authors.affiliation: Department Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX 76019, USA. Electronic address: matthew.fujita@uta.edu.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Fujita
authors.affiliation: Department of Conservation and Research, The Toledo Zoo, P.O. Box 140130, Toledo, OH 43614-0130, USA. Electronic address: peter.tolson@toledozoo.org.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Tolson
authors.affiliation: Bureau of Fisheries and Wildlife, Department of Natural and Environmental Resources, P.O. Box 366147, San Juan, PR 00936-6147, USA; Center for Applied Tropical Ecology and Conservation, University of Puerto Rico, P.O. Box 23341, Río Piedras, PR 00931-3341, USA. Electronic address: isladelamona@gmail.com.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: García
mesh_terms: D000818:Animals; D005075:Biological Evolution; D017821:Boidae / Q000145:classification / Q000235:genetics*; D017691:Caribbean Region; D003247:Conservation of Natural Resources; D004272:DNA, Mitochondrial / Q000737:chemistry; D056727:Endangered Species; D051456:Gene Flow; D040961:Genetic Drift; D014644:Genetic Variation; D062312:Islands; D010802:Phylogeny; D058974:Phylogeography
chemical_list: D004272:DNA, Mitochondrial
keywords: Conservation; Endangered species; Phylogeography; Population genetics; Puerto Rico; Snake