The relationship between limb reduction, body elongation and geographical range in lizards (Lerista,Scincidae)

Abstract

Aim The relationship between changes in body form (limb reduction and body elongation) and geographical range size was investigated across 68 species of Lerista, a species‐rich clade of Australian scincid lizards that exhibits extensive interspecific variability in both body form and range size. Location Lerista occurs across the entire Australian mainland, with diversity concentrated in arid and semi‐arid regions. Methods Geographical range size was estimated directly from c. 14,000 museum specimens using bioclimatic modelling in MaxEnt. Body form was quantified using principal components analysis of morphometric variables. Comparative analyses testing for a correlation between these two variables used a full Bayesian approach that accounts for uncertainties in trait optimization as well as in tree topology and branch lengths. Results A serpentine body form (elongated with reduced limbs) was significantly associated with smaller geographical range size, in both phylogenetically corrected and uncorrected analyses – but only if species from single localities (whose ranges could not be modelled using the above methods) were excluded. Main conclusions These results suggest a general predictive relationship between body form and geographical range size in lizards: elongate, limb‐reduced lizards tend to exhibit more restricted geographical ranges that may reflect reduced dispersal ability and may also predispose them to greater vulnerability of extinction.

The measure of success: geographic isolation promotes diversification in Pachydactylus geckos

“…While the heritability of range size has been demonstrated for many lineages, possible mechanistic explanations have varied, and include niche breadth [27], dispersal ability [76, 77], and morphological characteristics [26, 78] of lineages, as well as the geographic limits of biomes, landmasses, or hydrological basins [79]. In many cases, these factors may be interlinked.…”

“…The heritability of range size has been a matter of debate, but increasing numbers of studies demonstrate its heritability [21–25]. In at least some clades, including lizards, this heritability is associated with variable morphological or ecological traits [26, 27]. Likewise, numerous studies have reported trait-associated variation in diversification rates, especially since the development of BiSSE (binary-state speciation and extinction) and related models [28].…”

Overcoming phylogenetic and geographic uncertainties to test for correlates of range size evolution in gymnophthalmid lizards

“…B) may suggest morphologically induced dispersal costs (Gaston and Blackburn , Agosta et al ). Exemplifying this case, Lee et al () found that while typical lizards showed both big and small ranges, limbless ones showed only smaller ranges. The lower bounds of such relationships can be imposed by the minimum measuring unit size (e.g.…”

“…The low energetic requirements and often relatively small size of terrestrial ectothermic animals raise the question of whether energetic requirements would be an important correlate of range size, or if dispersal costs might be more important. The limited evidence available on this topic is still conflicting, with some studies showing significant relationships between body size and range size, whereas others not (Taylor and Gotelli , reviewed by Gaston and Blackburn , Lee et al , see Discussion). This evidence mostly comes from unifactorial studies that did not control for phylogenetic relationships in the tests or any kind of uncertainties.…”

Taxonomy of the Sand Sliders of Western Australia’s central coast (genus Lerista, Squamata: Scincidae): recognition of Lerista miopus (Günther, 1867)

“…Research has shown the development of limblessness within this genus to have occurred a number of times and is an unusually plastic condition, with a variety of conditions sometimes occurring within the same species (Amey & Worthington Wilmer 2014;Skinner 2010). The value of this situation in the study of limb loss has long been recognised (Benesch & Withers 2002;Greer 1987Greer , 1990Greer , 1992Lee et al 2013;Skinner 2010).…”