title: Distinct patterns of desynchronized limb regression in malagasy scincine lizards (squamata, scincidae).
abstract: Scincine lizards in Madagascar form an endemic clade of about 60 species exhibiting a variety of ecomorphological adaptations. Several subclades have adapted to burrowing and convergently regressed their limbs and eyes, resulting in a variety of partial and completely limbless morphologies among extant taxa. However, patterns of limb regression in these taxa have not been studied in detail. Here we fill this gap in knowledge by providing a phylogenetic analysis of DNA sequences of three mitochondrial and four nuclear gene fragments in an extended sampling of Malagasy skinks, and microtomographic analyses of osteology of various burrowing taxa adapted to sand substrate. Based on our data we propose to (i) consider Sirenoscincus Sakata & Hikida, 2003, as junior synonym of Voeltzkowia Boettger, 1893; (ii) resurrect the genus name Grandidierina Mocquard, 1894, for four species previously included in Voeltzkowia; and (iii) consider Androngo Brygoo, 1982, as junior synonym of Pygomeles Grandidier, 1867. By supporting the clade consisting of the limbless Voeltzkowia mira and the forelimb-only taxa V. mobydick and V. yamagishii, our data indicate that full regression of limbs and eyes occurred in parallel twice in the genus Voeltzkowia (as hitherto defined) that we consider as a sand-swimming ecomorph: in the Voeltzkowia clade sensu stricto the regression first affected the hindlimbs and subsequently the forelimbs, whereas the Grandidierina clade first regressed the forelimbs and subsequently the hindlimbs following the pattern prevalent in squamates. Timetree reconstructions for the Malagasy Scincidae contain a substantial amount of uncertainty due to the absence of suitable primary fossil calibrations. However, our preliminary reconstructions suggest rapid limb regression in Malagasy scincids with an estimated maximal duration of 6 MYr for a complete regression in Paracontias, and 4 and 8 MYr respectively for complete regression of forelimbs in Grandidierina and hindlimbs in Voeltzkowia.
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive, Centre National de la Recherche Scientifique, Montpellier, France; Division of Evolutionary Biology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Miralles
authors.affiliation: Museum für Naturkunde, Leibniz-Institut für Evolutions und Biodiversitätsforschung, Berlin, Germany; University of Melbourne, School of BioSciences, Melbourne, Victoria, Australia.
authors.forename: Christy A
authors.initials: CA
authors.lastname: Hipsley
authors.affiliation: Division of Evolutionary Biology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany; Biosystematics Group, Wageningen University, Droevendaalsesteeg, Wageningen, The Netherlands.
authors.forename: Jesse
authors.initials: J
authors.lastname: Erens
authors.affiliation: Centro de Biociencias, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gehara
authors.affiliation: Division of Evolutionary Biology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany; Département de Biologie Animale, Université d'Antananarivo, Antananarivo, Madagascar.
authors.forename: Andolalao
authors.initials: A
authors.lastname: Rakotoarison
authors.affiliation: Zoologische Staatssammlung München, München, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Glaw
authors.affiliation: Museum für Naturkunde, Leibniz-Institut für Evolutions und Biodiversitätsforschung, Berlin, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Müller
authors.affiliation: Division of Evolutionary Biology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany.
authors.forename: Miguel
authors.initials: M
authors.lastname: Vences
mesh_terms: D000818:Animals; D006614:Hindlimb / Q000033:anatomy & histology* / Q000502:physiology*; D008116:Lizards / Q000033:anatomy & histology* / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*