Phelsuma mutabilis

Rocha, Sara, Rösler, Herbert, Gehring, Philip-Sebastian, Glaw, Frank, Posada, David, Harris, James & Vences, Miguel, 2010, Phylogenetic systematics of day geckos, genus Phelsuma, based on molecular and morphological data (Squamata: Gekkonidae), Zootaxa 2429, pp. 1-28 : 13

Phelsuma mutabilis group

(contains P. b o r a i [named P. sp. aff. mutabilis in Rocha et al. 2009], P. breviceps , and P. m u t a b i l i s)

The three species in this group inhabit southwestern ( P. breviceps , P. mutabilis ) and western Madagascar ( P. mutabilis , P. borai ). Close relationships between P. b re v i c e p s and P. m u t a b i l i s had already been hypothesized based on morphometric and scale features ( Loveridge 1942); in fact, the two species have been synonymized and resurrected several times ( Loveridge 1942; Blanc 1972; Kluge 1991; Raxworthy & Nussbaum 1994). The mitochondrial and combined molecular data recover this group as monophyletic, although the nuclear data alone fail to support this grouping ( Fig. 3 ). Furthermore, the combined analysis recovers a monophyletic P. mutabilis sister to the very divergent P. b o r a i.

Genetic distances within this clade are high: average uncorrected p-distance between P. breviceps and P. mutabilis for cytochrome b is of 18.9%, with the distance of P. borai to P. breviceps (22.1%) and to P. mutabilis (23.5%) being even higher. Cytochrome b p-distances within P. m u t a b i l i s reach 8% (see also Glaw et al. 2009).

Species in the P. mutabilis group share, among other character states, the absence of bright green colour, non-gluing egg laying behaviour, a relatively low number of sublabials (5–6), smooth ventrals and subcaudals, and absence of nostril-rostral contact ( Tables 1-2 ).

The combined mitochondrial data ( Fig. 3 b) indicate possible affinities of the P. mutabilis group with P. andamanense . However, this grouping received less than 50% bootstrap and very low Bayesian support and warrants further analysis.

The lineage containing all species from the Mascarene Islands was previously studied in detail by Austin et al. (2004) with a considerably better sampling including the two extinct species P. edwardnewtonii and P. gigas . Corroborating previous results, we also consistently recovered it as a strongly supported monophyletic clade (clade B in Fig. 4 ). Clearly recovered by both the mitochondrial and combined data, P. guentheri is basal to the remaining species, and appears to have differentiated from these at an early stage of the Mascarene radiation although the two extinct species, not included in our study, might have been even more basal ( Austin et al. 2004).

The extant species in the P. cepediana group are quite variable in many morphological and chromatic characters but share egg-gluing behaviour, smooth ventralia and subcaudalia, a contact between rostral and nostril (apparently all except P. rosagularis ), and a high number of midbody scales (87 or more) ( Tables 1–2 ). Phelsuma guentheri differs from all extant species in the P. cepediana group (including P. edwardnewtonii ), and all other Phelsuma species, by the ability to change the pupil to a vertical slit. This and its associated "crepuscular" activity, as in the closely related (and extinct) P. gigas , are most probably of secondary origin ( Austin 2004).

Figures

FIGURE 3. Molecular phylogeny of the Phelsuma mutabilis group as calculated from the multi-gene dataset of Rocha et al. (2009). Shown are the respective clades from the Bayesian 50 % majority-rule consensus trees based on (a) the combined dataset of mitochondrial and nuclear genes, (b) the mitochondrial genes only, and (c) the nuclear genes only. See caption to Fig. 2 for further explanations.

FIGURE 4. Molecular phylogeny of the Phelsuma cepediana group as calculated from the multi-gene dataset of Rocha et al. (2009). Shown are the respective clades from the Bayesian 50 % majority-rule consensus trees based on (a) the combined dataset of mitochondrial and nuclear genes, (b) the mitochondrial genes only, and (c) the nuclear genes only. See caption to Fig. 2 for further explanations.