Evolution and maintenance of colour pattern polymorphism in Liopholis (Squamata:Scincidae)

Abstract

Abstract. We examined the evolution and maintenance of colour pattern polymorphism in an Australian lineage of scincid lizards, the genus Liopholis. Liopholis comprises 11 species, with representatives in both the temperate zone and arid zone. Specimens from all major Australian museums were examined to characterise colour pattern polymorphism within Liopholis, and investigate geographic variation in the relative abundance of morphs within polymorphic species. We used a previously published phylogeny for Liopholis to investigate the evolution and maintenance of colour pattern polymorphism within the group. Five species were found to exhibit colour pattern polymorphismslateri Storr, L. striata Sternfeld). Three colour morphs occur in L. whitii, with the relative abundance of each varying significantly among latitudes. The patterned morph is most common, while the incidence of the plain-back morph decreases at latitudes higher than 35°S. The L. whitii patternless morph occurs only within a narrow latitudinal band (34-38°S). In L. multiscutata, the relative abundance of the patterned (~89-93%) and patternless morph (~7-11%) is consistent across regions, except for the Nullarbor Plain region where the patternless morph is more common (~39%). Our analyses suggest a single origin of colour pattern polymorphism in Liopholis, followed by the subsequent loss of polymorphism on four occasions. The secondary loss of polymorphism might be associated with climate or habitat, possibly as the result of shifts into the arid zone or alpine regions of Australia. This study provides the necessary framework for future studies of colour pattern polymorphism in Liopholis.

Phylogeographic structure, demographic history and morph composition in a colour polymorphic lizard

“…Applying a conservative mitochondrial calibration of 2% sequence divergence per million years, the existence of three major lineages (‘NFR’, ‘SFR/OR’ and ‘LR/KI’; 3.7–6.4% net sequence divergence in mtDNA) within C. decresii sensu stricto is consistent with repeated contraction to, and expansion from, isolated refugia during Pleistocene glacial–interglacial cycles (Byrne, ). Although no obvious geographic barriers exist between the Northern and Southern Flinders Ranges, the climate is more arid in the Northern Flinders Ranges (Schwerdtfeger & Curran, ; Brandle, ), and the division between the ‘NFR’ and ‘SFR/OR’ lineages corresponds to phenotypic divergence observed in rock‐dwelling skinks (Chapple et al ., ) and geckos (Sistrom et al ., ), and the southerly range limit of the closely related red‐barred dragon, C. vadnappa (Wilson & Swan, ). The Flinders and Mt Lofty Ranges are separated by an expanse of low‐lying grassland which we refer to here as the Barossa Valley (Fig.…”

Has contemporary climate change played a role in population declines of the lizard Ctenophorus decresii from semi-arid Australia?

“…The climate of the northern region is more arid (Brandle, 2001;Schwerdtfeger and Curran, 1996), and the divide between these two regions also corresponds to phenotypic divergence in skinks and geckos (Chapple et al, 2008;Sistrom et al, 2012), suggesting the climate between these two regions may be distinct enough to drive differential evolution in lizards.…”

The effect of skin reflectance on thermal traits in a small heliothermic ectotherm

“…For instance, the presence of a strong latitudinal cline in morph frequency, where the relative frequency of striped versus unstriped individuals decreases from north (e.g., tropical climate) to south (e.g., temperate climate), suggests that climate may play a role in the evolution of colour variation (Forsman and Shine, 1995). Similar latitudinal and altitudinal patterns have been exhibited in other ectothermic vertebrates such as the White's skink (Liopholis whittii) as well as montane populations of adders (V. berus) and asp viper (V. aspis) (Broennimann et al, 2014;Chapple et al, 2008). Likewise, further research is warranted given that we did not assess thermal traits under varying solar conditions.…”