Molecular Phylogeography of the Endemic Five-lined Skink (Plestiodon marginatus) (Reptilia: Scincidae) of the Ryukyu Archipelago, Japan, with Special Reference to the Relationship of a Northern Tokara Population¹

Abstract

Phylogenetic relationships were inferred for populations of the Ryu-kyu five-lined skink Plestiodon marginatus, a species showing an extraordinary distribution across the Tokara Tectonic Strait. Phylogenetic analyses of 809 base positions of the mitochondrial 12S and 16S rRNA genes supported collective divergence of the southern Tokara and northern Amami populations, which have been classified as P. m. oshimensis. A population from Nakanoshima, an island of the Tokara Group north of the Tokara Tectonic Strait, has the closest affinity with the Okinawajima population of P. m. marginatus rather than with the geographically closer southern Tokara and northern Amami populations. This result is concordant with that of a recent allozyme study and suggests an origin of the Nakanoshima population through long-distance dispersal from the Okinawa Island Group. Also, our results strongly suggest a closer relationship of a population of P. m. oshimensis from Okinoerabujima, a southern island of the Amami Group, with P. m. marginatus from Okinawajima than with the ''consubspecific'' southern Tokara and northern Amami populations. Both Na-kanoshima and Okinoerabujima populations are usually referred to as P. m. oshi-mensis, and therefore our results indicate nonmonophyly of P. m. oshimensis in the current taxonomic arrangement.

The phylogenetic systematics of blue-tailed skinks (Plestiodon) and the family Scincidae

“…However, the analysis of mtDNA strongly supports the sister relationship of P. elegans and P. stimpsonii (Fig. S2), a result that is congruent with Honda et al . (2008)'s analysis of mitochondrial 12S and 16S ribosomal RNA but incongruent with the concatenated data.…”

“…The sister relationship between P. chinensis and P. kishinouyei confirms the hypothesis of Taylor (1935) and Honda et al . (2008): that these species are closely related.…”

“…A recent phylogenetic analysis of mtDNA ( 12S and 16S mitochondrial rRNA: Honda et al ., 2008) strongly supports the sister relationship of P. elegans and P. stimpsonii , to the exclusion of P. marginatus . This sister relationship contrasts with the results of previous allozyme (Kato et al ., 1994) and morphological (Hikida, 1993) analyses that inferred the sister relationship of P. marginatus and P. stimpsonii .…”

“…Previous molecular studies included no more than half of the described species (e.g. Schmitz, Mausfeld & Embert, 2004; Brandley, Schmitz & Reeder, 2005), and have usually focused on regional subsets of the genus' range in the USA (Murphy, Cooper & Richardson, 1983; Richmond & Reeder, 2002; Macey et al ., 2006; Richmond, 2006) and Asia (Kato, Ota & Hikida, 1994; Hikida & Motokawa, 1999; Motokawa & Hikida, 2003; Okamoto et al ., 2006; Honda et al ., 2008; Okamoto & Hikida, 2009). Moreover, multiple studies have inferred conflicting or poorly supported placements of Plestiodon within the scincid tree of life (Whiting, Bauer & Sites, 2003; Brandley et al ., 2005; Austin & Arnold, 2006).…”

Late Pleistocene lineage divergence among populations ofNeolitsea sericea(Lauraceae) across a deep sea‐barrier in the Ryukyu Islands

“…According to a commonly held view (e.g. Honda et al, 2008;van der Geer et al, 2010;Nakamura et al, 2010), both the Tokara and Kerama gaps have probably never been closed since their origin, as a result of tectonics, in the Pliocene (c. 5.3-1.8 Ma). This 'ancient sea-barrier hypothesis' is mainly derived from studies of Ota (1998) on the distribution and phylogenetic relationships of the Ryukyu herpetofauna.…”