Lizard scales in an adaptive radiation: variation in scale number follows climatic and structural habitat diversity in<i>Anolis</i>lizards

Wegener, Johanna E.; Gartner, Gabriel E. A.; Losos, Jonathan B.

doi:10.1111/bij.12380

Cited by 38 publications

(41 citation statements)

References 43 publications

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“…This is not to say that no adaptive diversification has occurred in anoles since the Miocene. Rather, there has been considerable subdivision of ecomorph niches as species specialize for different thermal microhabitats (26)-unfortunately, the scalation characters that tend to correlate with thermal biology (27) were not preserved in most fossils, preventing inferences about the evolution of thermal specialization. Our data do confirm, however, that the subsequent division of the trunkcrown anole niche into small and large species, presumably to partition prey resources (21), also has an ancient origin, again in agreement with molecular divergence estimates.…”

Section: Resultsmentioning

confidence: 99%

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Sherratt

Castañeda

Garwood

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Whether the structure of ecological communities can exhibit stability over macroevolutionary timescales has long been debated. The similarity of independently evolved Anolis lizard communities on environmentally similar Greater Antillean islands supports the notion that community evolution is deterministic. However, a dearth of Caribbean Anolis fossils-only three have been described to datehas precluded direct investigation of the stability of anole communities through time. Here we report on an additional 17 fossil anoles in Dominican amber dating to 15-20 My before the present. Using data collected primarily by X-ray microcomputed tomography (X-ray micro-CT), we demonstrate that the main elements of Hispaniolan anole ecomorphological diversity were in place in the Miocene. Phylogenetic analysis yields results consistent with the hypothesis that the ecomorphs that evolved in the Miocene are members of the same ecomorph clades extant today. The primary axes of ecomorphological diversity in the Hispaniolan anole fauna appear to have changed little between the Miocene and the present, providing evidence for the stability of ecological communities over macroevolutionary timescales.adaptive radiation | ecomorph | Hispaniola | Miocene | Anolis

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Section: Resultsmentioning

confidence: 99%

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Sherratt

Castañeda

Garwood

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…In dry and hot environments, large scales reduce the loss of water by evaporation and dissipate heat faster than small scales (Alibardi 2003;Huey et al 2009;Sinervo et al 2010), mostly because large scales per unit or skin surface offer fewer imbrications where water may be lost. For this reason, species that occur in warm and dry habitats are expected to have larger dorsal scales (to facilitate radiation and conductivity of heat and prevent water loss), whereas those that occur in cool and wet habitats are expected to have smaller dorsal scales (to minimize heat loss) (Soulé 1966;Soulé & Kerfoot 1972;Regal 1975;Lister 1976;Calsbeek et al 2006;Wegener et al 2014). Nevertheless, although (as mentioned above) ectotherms are vulnerable to temperature fluctuations, particularly in face of global warming (Parsons 1990;Pounds et al 1999;Root et al 2003;Parmesan 2006;Colwell et al 2008;Deutsch et al 2008;Raxworthy et al 2008;Tewksbury et al 2008;Williams et al 2008;Chen et al 2009;Kearney et al 2009;Sinervo et al 2010;Bhöm et al 2013), little attention has been paid to the permeability of the skin in the reptile order Squamata (Spinner et al 2014;Wegener et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Are the number and size of scales in Liolaemus lizards driven by climate?

Tulli

Cruz

2018

Integrative Zoology

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Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they occur. To buffer these fluctuations, ectotherms use different strategies, including the integument, which is a barrier that minimizes temperature exchange between the inner body and the surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape and texture, and its main function is protection, water loss avoidance and thermoregulation. The size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it has also been observed that in some groups of Iguanian lizards it could be related to phylogeny. Thus, here, we studied the area and number of scales (dorsal and ventral) of 60 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate, and found that the number and size of scales are related to climatic variables, such as temperature and geographical variables as altitude. The evolutionary process that best explained how these morphological variables evolved was the Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry, whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is, thus, under less pressure to change in response to alterations in external conditions. It is possible that scale ornamentation, such as keels and granulosity, may bring some more information in this regard.

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“…; Wegener et al. ). Indeed, scale number per unit length is often a strong predictor of scale size, as it explains approximately 95% of the interspecific variation in scale size among Liolaemus species, for instance (Tulli & Cruz, ).…”

Section: Discussionmentioning

confidence: 96%

Ontogenetic scaling patterns of lizard skin surface structure as revealed by gel‐based stereo‐profilometry

Baeckens

Wainwright

Weaver³

et al. 2019

Journal of Anatomy

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The skin surface structure of squamate reptiles varies greatly among species, likely because it plays a key role in a range of tasks, such as camouflage, locomotion, self‐cleaning, mitigation of water loss and protection from physical damage. Although we have foundational knowledge about squamate skin morphology, we still know remarkably little about how intraspecific variation in skin surface structure translates to functional variation. This gap in our understanding can be in part traced back to: (i) our lack of knowledge on how body size determines skin surface structure; and (ii) the lack of means to perform high‐throughput and detailed analysis of the three‐dimensional (3D) anatomy of reptilian skin surfaces in a non‐destructive manner. To fill this gap, we explored the possibilities of a new imaging technique, termed gel‐based stereo‐profilometry, to visualize and quantify the 3D topography of reptilian skin surface structure. Using this novel approach, we investigated intra‐specific and intra‐individual variation in the skin surface morphology of a focal lizard species, Anolis cristatellus. We assessed how various characteristics of surface topography (roughness, skew and kurtosis) and scale morphology (area, height, width and shape) scale with body size across different body regions. Based on an ontogenetic series of A. cristatellus males, we show that skin roughness increases with body size. Skin patches on the ventral body region of lizards were rougher than on the dorsum, but this was a consequence of ventral scales being larger than dorsal scales. Dorsal surface skew and kurtosis varied with body size, but surfaces on the ventral skin showed no such relationship. Scale size scaled isometrically with body size, and while ventral scales differed in shape from dorsal scales, scale shape did not change with ontogeny. Overall, this study demonstrates that gel‐based stereo‐profilometry is a promising method to rapidly assess the 3D surface structure of reptilian skin at the microscopic level. Additionally, our findings of the explanatory power of body size on skin surface diversity provide a foundation for future studies to disentangle the relationships among morphological, functional and ecological diversity in squamate reptile skin surfaces.

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Lizard scales in an adaptive radiation: variation in scale number follows climatic and structural habitat diversity inAnolislizards

Cited by 38 publications

References 43 publications

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Amber fossils demonstrate deep-time stability of Caribbean lizard communities

Are the number and size of scales in Liolaemus lizards driven by climate?

Ontogenetic scaling patterns of lizard skin surface structure as revealed by gel‐based stereo‐profilometry

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