Journal of Biogeography
SUPPORTING INFORMATI ON
Older than the islands: origin and diversification of Galápagos leaf-toed geckos
(Phyllodactylidae: Phyllodactylus) by multiple colonizations
Omar Torres-Carvajal, Charles W. Barnes, María J. Pozo-Andrade,
Washington Tapia and Gabriela Nicholls
Appendix S3 Diversity and taxonomy of Galápagos leaf-toed geckos
Six species were recognized in the first taxonomic revision of Galápagos leaf-toed
geckos (Van Denburgh, 1912). Except for P. tuberculosus, a North American species
that was thought to occur in the Galápagos until recognized as a separate species
endemic to San Cristóbal (Taylor, 1942), Van Denburgh’s species-level taxonomy
remains intact. All but two species – P. baurii and P. galapagensis – are restricted to a
single island. Phyllodactylus baurii was described by Garman (1892) from Floreana,
but populations from Española were regarded as the same species by Van Denburgh
(1912), based on morphology. Populations on these two islands were later regarded
as separate taxa by Lanza (1973), who recognized them as two subspecies. Our phylogenetic hypotheses (see Figs 2 & 3) strongly support the paraphyly of P. baurii, which
is split into two clades corresponding to Floreana and Española. The ND4 genetic
distance between them (0.14) is similar to distances between P. baurii from Floreana
and other recognized species from Galápagos in the same clade (0.12–0.15), except for
P. galapagensis, with distance values between 0.06–0.09 (see Appendix S1). We therefore designate the population in Española as a separate species, P. gorii, originally
described by Lanza (1973) as a subspecies of P. baurii Garman, 1892.
Van Denburgh (1912) and Lanza (1973) also recognized five subspecies within
the widely distributed P. galapagensis which, as currently recognized, occurs on most
of the central and western islands and islets, including Baltra, Bartolomé, Cowley,
Daphne, Fernandina, Isabela, Islote Mares, Pinzón, Plaza Norte, Plaza Sur, Santa Cruz,
Santiago, Seymour and Tortuga (Van Denburgh, 1912; Lanza, 1973).
Based on the general lineage concept of species (de Queiroz, 1998), we recognize four species within P. galapagensis, corresponding to the following species and
island groups: P. galapagensis (Santa Cruz and Caamaño islet off that island), P. galapagensis (Isabela), P. galapagensis (Pinzón) and P. galapagensis (Santiago). These
species are readily identified based on genetic distances (see Appendix S1), reciprocal
monophyly (see Fig. 2), geographical distribution (allopatry), and in some cases
morphological differences (Van Denburgh, 1912; Lanza, 1973). Following the taxonomic arrangements of Van Denburgh (1912) and Lanza (1973), including the restriction
of the type locality of P. galapagensis to Santa Cruz (Lanza, 1973), we recognize the
populations in Santa Cruz and Caamaño islet off Santa Cruz as P. galapagensis Peters,
1869, and those populations in Pinzón as P. duncanensis Van Denburgh, 1912. No
names are available for the populations in Isabela and Santiago, but Van Denburgh
(1912) and Lanza (1973) described one subspecies each from islands near Santiago
(Daphne and Islote Mares, respectively) that were not included in our analyses and
could represent the same species as those sampled from Santiago for this study.
Future studies including a larger geographical sampling of leaf-toed geckos from the
Galápagos will help answer this and other questions, such as the origin of P. gilberti
from Wolf Island.
Active research on the Galápagos archipelago during the last 150 years has
resulted in a large number of scientific papers and books (2656 Galápagos results in
Scopus, 9 September 2013). The discoveries in the 21st century of the pink iguana
endemic to Wolf volcano in northern Isabela (Gentile & Snell, 2009) and an unnamed
species of giant tortoise from Santa Cruz (Russello et al., 2005; Chiari et al., 2009) are
therefore remarkable. Additionally, three species of lava lizards (Microlophus barringtonensis, M. indefatigabilis and M. jacobi) have been resurrected from previous
synonymy (Benavides et al., 2007; Benavides et al., 2009). Following this recent trend
of species discoveries in the Galápagos, we identify four independent evolutionary
lineages of leaf-toed geckos and propose that they be recognized as separate species
(P. duncanensis, P. gorii, P. sp. 1 and P. sp. 2). In less than a decade, systematic studies
have increased the number of recognized reptile species from this archipelago by
33%. This suggests that similar studies with other groups of organisms might reveal
that the diversity of the biota of Galápagos is currently underestimated.
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