Tarentola gigas, (BOCAGE, 1875)

Vasconcelos, Raquel, Perera, Ana, Geniez, Philippe, Harris, D. James & Carranza, Salvador, 2012, An integrative taxonomic revision of the Tarentola geckos (Squamata, Phyllodactylidae) of the Cape Verde Islands, Zoological Journal of the Linnean Society 164 (2), pp. 328-360 : 350-351

TARENTOLA GIGAS ( BOCAGE, 1875)

Diagnosis: Giant gecko with SVL above 100 mm [maximum SVL 155 mm ( Bocage, 1896), 103.6 mm on average; ( Schleich, 1987)]; eye/ear opening ratio 1.5– 2.0 ( Schleich, 1987); ear–eye/eye–snout distance ratio slightly ³ 1 ( Schleich, 1984, 1987). Eight to 12 supralabials and seven to nine infralabials ( Schleich, 1984); eight to 12 enlarged lamellae under the 4th finger; 160–195 midbody scales ( Joger, 1984b); flatter apical dorsal tubercles ( Fig. 5D 1 ) with 16 transverse rows ( Schleich, 1984); several enlarged tubercles between the eye and the ear opening. Grey dorsal or olive greyish pattern with a broad, light well-defined middorsal line with generally five large saddle-like marks ( Figs 6D 1 , 7D 1 ); cream ventral parts, yellow on the lower parts; big dark spots on the labials, creating an alternating light and dark pattern; eye iris dark grey with a typical vertical light area around the pupil, joining the upper and lower parts of the eye which are also light.

It differs from other Tarentola from the same clade D, T. ‘ rudis ’ from Santiago, Fogo, Brava, Rombos, and Maio, besides from its size, by the absence of a keel on dorsal tubercles. Unlike all other Cape Verdean Tarentola , strong vocalisations play a clear role in social behaviour ( Schleich, 1982b, 1987). This species avoids vertical surfaces presumably due to its weight, and presents a robust body with typical extreme fat storage ( Schleich, 1987).

Distribution: Raso and Branco Islets, Cape Verde.

Genetic and phylogeographic remarks: Tarentola gigas is monophyletic in the mtDNA tree from Figure 2 . Genetic divergence with other taxa within clade D is higher than among taxa within clade B, although lower than among members of clade A: D1–D2, D1–D3, D1–D4, D1–D5, and D1–D6 p- dist (cyt b) = 2.4 ± 0.8, 2.8 ± 0.9, 2.6 ± 0.9, 2.8 ± 0.9, and 3.9 ± 1.0%, respectively ( Table 5). Most of the Snn test values for PDC, ACM4, and MC1R are not significant among this clade (Appendix 5). According to the presently selected protocol of integration (IPC), a minimum of two lines of evidence differentiate T. gigas from all the other Tarentola from Cape Verde except T. protogigas from which it differs only in morphology ( Fig. 2 ). Consequently, it is considered a different species, although not fulfilling the rule in respect to T. protogigas , due to several ecological, behavioural and geographical differences (see Discussion).

The two subspecies, T. g. gigas and T. g. brancoensis, are not reciprocally monophyletic ( Fig. 2 ) and the level of genetic divergence is very low, p- dist (cyt b) = 0.2 ± 0.2% (data not shown). Only one of the three lines of evidence (morphology) differentiates the two island populations. Consequently, according to the IPC protocol, these are considered distinct subspecies ( Figs 2 , 3 and Appendix 3).

Figures

Figure 1. Map of the Cape Verde Islands showing the geographical location (latitudes and longitudes) and altitudes of the islands and the origins of the new Tarentola samples included in the genetic (circles) and morphological (diamonds) analyses (Geographic Coordinate System, Datum WGS 84). Island and taxa colours match the colours used on the network analyses. No specimens were found on Sal.

Figure 2. Phylogenetic relationships of endemic Cape Verde Tarentola taxa and their relatives from the Canary Islands modified from Vasconcelos et al. (2010) based on cytochrome b and 12S rRNA genes. The tree was inferred using maximum likelihood (ML) and GTR+I+G model of sequence evolution (log likelihood = -6468.896) and was rooted using Tarentola americana. Bootstrap support values above 60% for the ML analysis are shown below nodes. Posterior probability (PP) values higher than 95% for the Bayesian analysis are represented by an asterisk (*) and are shown above nodes. Names in bold follow the new taxonomic proposal and non-bold ones the taxonomy accepted in previous recent papers (Carranza et al., 2000; Jesus et al., 2002; Vasconcelos et al., 2010). For further details see Vasconcelos et al. (2010). Characters immediately to the right of island names correspond to the 15 evolutionarily significant units (ESUs) of A, B, C, and D clades recognized in the present work and represented in split green bars. Lines of evidence (in grey): 1, mitochondrial DNA (independent cyt b parsimony networks with a connection limit of 95%; see Appendix 3); 2, nuclear DNA (absence of shared haplotypes in MC1R); 3, morphology (detection of any diagnostic morphological character or a set of a unique combination of characters). Integration approaches (in red) from the most conservative to the most inflationist: ITC stands for integration by total congruence (all lines of evidence should be congruent), IPC stands for integration by partial congruence, retained in the present study (at least two lines of evidence are necessary); IC stands for integration by cumulation (one line of evidence is sufficient). Species are represented in split red bars and subspecies in yellow.

Figure 3. Parsimony networks corresponding to the PDC, ACM4 and MC1R nDNA sequence variation in Tarentola from the Cape Verde Islands. Lines represent a mutational step, circles haplotypes and dots missing haplotypes. The size of circles is proportional to the number of haplotypes and colours to the number of individuals. The dotted circles represent the most probable ancestral haplotype. Samples from the same island are similarly coloured but with different tonalities for different taxa. For correspondences of sample and location codes see Appendix 1.

Figure 5. Magnified dorsal tubercles of Tarentola species of the Cape Verde Islands.

Figure 6. Typical dorsal patterns of Tarentola species of the Cape Verde Islands (adapted from Joger, 1993).

Figure 7. Photographs of the dorsal and lateral views of Tarentola of the Cape Verde Islands. A1, T. boavistensis; A2, T. bocagei; A3, T. fogoensis; A4, T. darwini; B1, T. substituta; B2, T. raziana; B3, T. caboverdiana; C, T. nicolauensis; D1, T. gigas (T. gigas brancoensis on the left and T. gigas gigas on the right); D2, T. rudis; D3, T. protogigas protogigas; D4, T. p. hartogi from Brava Island; D5, T. p. hartogi from Rombos Islets; D6, T. maioensis.