Wednesday, November 30, 2016

[Herpetology • 2017] Endemic Diversification in the Mountains: Genetic, Morphological, and Geographical Differentiation of the Hemidactylus Geckos in southwestern Arabia


 Hemidactylus asirensis Halfarraji 
Šmíd, Shobrak, Wilms, Joger & Carranza, 2016
 


Abstract
In this study, we provide genetic, morphological, and geographical comparisons for 11 species of the southwestern Arabian radiation of Hemidactylus geckos, nine of which are endemic to the region. By using a coalescence-based species-tree reconstruction in combination with divergence time estimations and speciation probability testing, we show that most of the speciation events occurred in the Pliocene, which is more recent than previously thought based on calibrations of concatenated data sets. The current dating indicates that the changing climate at the beginning of the Pliocene, from hot and dry to cold and wet, is likely responsible for increased speciation in Hemidactylus. Analyses of geographic and altitudinal overlap of the species and their morphological differentiation show that most species do not occur in sympatry. Those that overlap geographically are usually differentiated by their altitudinal preference, head shape, body size, or their combination. Our results indicate that the topographically complex mountains of southwestern Arabia support a significant radiation of Hemidactylus geckos by allowing multiple allopatric speciation events to occur in a relatively small area. Consequently, we describe two new species endemic to the Asir Mountains of Saudi Arabia, H. alfarraji sp. n. and H. asirensis sp. n., and elevate two former subspecies of H. yerburii to species levelH. montanus and H. pauciporosus.

Keywords: Allopatry; Diversity; Gekkonidae; Radiation; Species delimitation; Species tree; Speciation


Figure 5: Holotypes and type localities of Hemidactylus alfarraji sp. n. and  H. asirensis sp. n.
a General body habitus of H. alfarraji sp. n. holotype (NMP 75269); b detail of its head; c detail of its precloacal region with preanal pores visible; d lamellae under the toes of left hind limb; e type locality 32 km W of Najran (1969 m a.s.l.), Najran Province, Saudi Arabia.
f General body habitus of H. asirensis sp. n. holotype (NMP 75271); g detail of its head; h detail of the precloacal region with preanal pores visible; i lamellae under the toes of left hind limb; j type locality Al Balhy (2376 m a.s.l.), Asir Province, Saudi Arabia 

Jiří Šmíd, Mohammed Shobrak, Thomas M. Wilms, Ulrich Joger and Salvador Carranza. 2016. Endemic Diversification in the Mountains: Genetic, Morphological, and Geographical Differentiation of the Hemidactylus Geckos in southwestern Arabia. Organisms Diversity & Evolution.  DOI: 10.1007/s13127-016-0293-3

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