On Gymnodactylus amarali Barbour, 1925, with the description of a new species (Sauria, Gekkonidae)

Abstract

Gymnodactylus amarali Barbour, 1925, was previously considered to be a subspecies of G. geckoides, with a wide distribution in the Brasilian cerrados. Examination of a specimen from Alto Parnaíba, Maranhão, near the type locality (Engenheiro Dodt, Piauí), indicates that it is a proper species, apparently limited to the upper Parnaíba basin. The form previously identified as G. geckoides amarali is described as a new species, G. carvalhoi, type locality Ipueiras, State of Tocantins, thus diagnosed: color pattern plain or, more often, with moderately contrasted ocelli; dorsal tubercles in 13 -16 poorly organized longitudinal rows (mode 14, 72%); 31 -49 tubercles in a paramedian row; 17 -22 transverse rows of ventral scales; 13 -18 infradigital lamellae on toe IV; tail longest in the genus. The new species is statistically compared to parapatric G. geckoides, widespread in the caatingas. Although only one meristic character (number of tubercle rows) is by itself diagnostic, the species are easily told apart. It is thought on provisional evidence that they are better considered for the time being as full species, not subspecies. A brief consideration is made of the speciation model that seems suitable, to wit, parapatric.

Out of the deep: Cryptic speciation in a Neotropical gecko (Squamata, Phyllodactylidae) revealed by species delimitation methods

“…The gecko Gymnodactylus amarali Barbour, 1925 is a Cerrado endemic with a wide distribution in the central and northern portions of the biome (Vanzolini, 2005). It was synonymized with Gymnodactylus geckoides Spix, 1825 by Vanzolini (1953), but later resurrected and restricted to the 'Alto Parnaíba' region (close to the type locality of Barbour, Vanzolini, 2005).…”

“…It was synonymized with Gymnodactylus geckoides Spix, 1825 by Vanzolini (1953), but later resurrected and restricted to the 'Alto Parnaíba' region (close to the type locality of Barbour, Vanzolini, 2005). A new species, Gymnodactylus carvalhoi Vanzolini, 2005, was described as the widespread form in the Cerrado (Vanzolini, 2005), but soon synonymized with G. amarali after Cassimiro and Rodrigues (2009) rechecked the type specimen and found that the diagnostic characters were highly variable within all Gymnodactylus sampled in the Cerrado.…”

“…It was synonymized with Gymnodactylus geckoides Spix, 1825 by Vanzolini (1953), but later resurrected and restricted to the 'Alto Parnaíba' region (close to the type locality of Barbour, Vanzolini, 2005). A new species, Gymnodactylus carvalhoi Vanzolini, 2005, was described as the widespread form in the Cerrado (Vanzolini, 2005), but soon synonymized with G. amarali after Cassimiro and Rodrigues (2009) rechecked the type specimen and found that the diagnostic characters were highly variable within all Gymnodactylus sampled in the Cerrado. Thus, five species of Gymnodactylus are currently recognized, all within the Brazilian territory: G. amarali, endemic to the Cerrado; Gymnodactylus darwinii (Gray, 1845), endemic to the Atlantic Rainforest; G. geckoides, endemic to the Caatinga; and two other species restricted to the Espinhaço mountain range, known only from the surroundings of their type localities: Gymnodactylus guttulatus Vanzolini, 1982, in the southernmost segment of the Espinhaço, and Gymnodactylus vanzolinii Cassimiro and Rodrigues, 2009, in the northern portion.…”

“…Dissimilarities noted between G. amarali and G. geckoides include ecological differences such as clutch and egg sizes (Colli et al, 2003), karyological differences in chromosome number and type (Pellegrino et al, 2009), and morphological differences in pholidosis and coloration patterns (Cassimiro and Rodrigues, 2009;Vanzolini, 1953Vanzolini, , 2005. Nonetheless, it remains unclear whether the widespread Cerrado populations of G. amarali form a monophyletic group in relation to its Caatinga counterpart.…”

“…In fact, it was proposed that relict populations of G. geckoides might be present in the core of the Cerrado region (Pellegrino et al, 2009), because the karyotype of one specimen was identical to the karyotype observed in G. geckoides populations. In addition, extensive chromosomal polymorphism has been observed within and between G. amarali populations (Pellegrino et al, 2009), as well as great morphological variation among populations (Cassimiro and Rodrigues, 2009;Vanzolini, 1953Vanzolini, , 2005. As such, it is possible that populations treated under the name G. amarali are paraphyletic in relation to G. geckoides and, moreover, that differences among G. amarali populations reflect the existence of cryptic species.…”