title: Molecular data from contemporary and historical collections reveal a complex story of cryptic diversification in the Varanus (Polydaedalus) niloticus Species Group.
abstract: Previous studies of color pattern, tongue pigmentation, and scale counts have been used to distinguish two species of semiaquatic varanids in Africa, but these findings have yet to be tested with molecular data. The Varanus (Polydaedalus) niloticus Species Group is comprised of the Nile monitor (V. niloticus) and the Ornate monitor (V. ornatus). Due to the high rate of exploitation of both species for bushmeat, the leather industry, and the pet trade, a clear understanding of the taxonomy and genetic partitioning is necessary for effective management. Here we utilize a multilocus approach, consisting of mitochondrial and nuclear markers, totaling 4251 bp, as well as microsatellite loci to assess the taxonomic validity and intraspecific evolutionary patterns within the V. niloticus Species Group. By incorporating historical specimens from museum collections as well as contemporary samples, we obtained range-wide coverage for both species across Africa. Concordant results from various approaches all suggest that V. ornatus does not represent a distinct monophyletic group. Our analyses recovered three genetic clades within V. niloticus, representing western, northern, and southern lineages. The western clade was found to diverge first, around 7.7 mya (95% HPD: 4.6-11.0 mya) and exhibits 8.4% and 8.7% uncorrected sequence divergence between the northern and southern V. niloticus clades, respectively. This geographically separate lineage corresponds to previous descriptions of Tupinambis stellatusDaudin (1802). These findings not only call for taxonomic revision of this species group, but also shed light on the biogeographic history of Africa as well as aid in the management planning of varanids and other co-distributed African species.
authors.affiliation: Department of Biological Sciences, Fordham University, 441 East Fordham Road, Bronx, NY 10458, United States. Electronic address: sdowell@fordham.edu.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Dowell
authors.affiliation: Museum of Vertebrate Zoology, University of California, Berkeley, 3101 Valley Life Sciences Building, Berkeley, CA 94720, United States. Electronic address: daniel.portik@berkeley.edu.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Portik
authors.affiliation: Département Histoire de la Terre, Muséum National d'Histoire Naturelle, CNRS-UMR 7207 (CR2P), Bâtiment de Géologie CC 48, 57 rue Cuvier, F-75231 Paris Cedex 05, France. Electronic address: vdebuff@mnhn.fr.
authors.forename: Vivian
authors.initials: V
authors.lastname: de Buffrénil
authors.affiliation: Institut de Systématique, Évolution, et Biodiversité (ISYEB - UMR 7205 CNRS, MNHN, UPMC, EPHE), Muséum National d'Histoire Naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France. Electronic address: ineich@mnhn.fr.
authors.forename: Ivan
authors.initials: I
authors.lastname: Ineich
authors.affiliation: Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, United States. Electronic address: egreenbaum2@utep.edu.
authors.forename: Eli
authors.initials: E
authors.lastname: Greenbaum
authors.affiliation: Department of Biological Sciences, Fordham University, 441 East Fordham Road, Bronx, NY 10458, United States. Electronic address: skolokotronis@fordham.edu.
authors.forename: Sergios-Orestis
authors.initials: SO
authors.lastname: Kolokotronis
authors.affiliation: Department of Biological Sciences, Fordham University, 441 East Fordham Road, Bronx, NY 10458, United States. Electronic address: ehekkala@fordham.edu.
authors.forename: Evon R
authors.initials: ER
authors.lastname: Hekkala
mesh_terms: D000349:Africa; D000818:Animals; D019143:Evolution, Molecular; D014644:Genetic Variation / Q000235:genetics*; D008116:Lizards / Q000235:genetics*; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA
keywords: African biogeography; Museum collections; Nile monitor; Ornate monitor; V. ornatus; V. stellatus