Introduction

Pianka, Eric R.; King, Dennis

doi:10.2307/j.ctt2005wjp.5

Cited by 26 publications

(57 citation statements)

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“…Varanus glebopalma is especially proficient in both behaviors (Sweet, 2004b); it habitually rushes after prey, sprints across boulder fields, and ascends vertical rock faces. Rocky substrate was therefore reflected in claw shape; claws were relatively short and high, similar to (although to a lesser degree than) Escarpment taxa.…”

Section: Discussionmentioning

confidence: 99%

“…Varanus scalaris and Varanus tristis may be found within grassland trees (Pianka, 2004; Smith, Sweet, & King, 2004; Sweet, 2007). Varanus mitchelli frequents mangroves in the riparian zone, and uses branches to launch into rivers (Schultz & Doody, 2004; Shine, 1986). …”

Section: Methodsmentioning

confidence: 99%

“…Riverbed consists solely of Varanus mertensi, which is almost always found in proximity to permanent freshwater (Christian, 2004a; pers. obs.).…”

Section: Methodsmentioning

confidence: 99%

“…These species cross open terrain, climb up rocks, and refuge within crevices. This group includes Varanus acanthurus, Varanus glebopalma, and Varanus kingorum (Dryden, 2004; King, 2004; Sweet, 2004b). …”

Section: Methodsmentioning

confidence: 99%

“…These species are rarely found in trees, and include Varanus gouldii and Varanus panoptes (Christian, 2004b; Thompson, 1995). …”

Section: Methodsmentioning

confidence: 99%

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Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild

D’Amore

Clulow

Doody

et al. 2018

Ecology and Evolution

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Numerous studies investigate morphology in the context of habitat, and lizards have received particular attention. Substrate usage is often reflected in the morphology of characters associated with locomotion, and, as a result, claws have become well‐studied ecomorphological traits linking the two. The Kimberley predator guild of Western Australia consists of 10 sympatric varanid species. The purpose of this study was to quantify claw size and shape in the guild using geometric morphometrics, and determine whether these features correlated with substrate use and habitat. Each species was assigned a Habitat/substrate group based on the substrate their claws interact with in their respective habitat. Claw morphometrics were derived for both wild caught and preserved specimens from museum collections, using a 2D semilandmark analysis. Claw shape significantly separated based on Habitat/substrate group. Varanus gouldii and Varanus panoptes claws were associated with sprinting and extensive digging. Varanus mertensi claws were for shallow excavation. The remaining species’ claws reflected specialization for some form of climbing, and differed based on substrate compliance. Varanus glauerti was best adapted for climbing rough sandstone, whereas Varanus scalaris and Varanus tristis had claws ideal for puncturing wood. Phylogenetic signal also significantly influenced claw shape, with Habitat/substrate group limited to certain clades. Positive size allometry allowed for claws to cope with mass increases, and shape allometry reflected a potential size limit on climbing. Claw morphology may facilitate niche separation within this trophic guild, especially when considered with body size. As these varanids are generalist predators, morphological traits associated with locomotion may be more reliable candidates for detecting niche partitioning than those associated directly with diet.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Riverbed consists solely of Varanus mertensi, which is almost always found in proximity to permanent freshwater (Christian, 2004a; pers. obs.).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…These species are rarely found in trees, and include Varanus gouldii and Varanus panoptes (Christian, 2004b; Thompson, 1995). …”

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild

D’Amore

Clulow

Doody

et al. 2018

Ecology and Evolution

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Dental microwear texture analysis along reptile tooth rows: complex variation with non-dietary variables

et al. 2021

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Dental microwear texture analysis (DMTA) is a powerful technique for reconstructing the diets of extant and extinct taxa. Few studies have investigated intraspecific microwear differences along with tooth rows and the influence of endogenous non-dietary variables on texture characteristics. Sampling teeth that are minimally affected by non-dietary variables is vital for robust dietary reconstructions, especially for taxa with non-occlusal (non-chewing) dentitions as no standardized sampling strategies currently exist. Here, we apply DMTA to 13 species of extant reptile (crocodilians and monitor lizards) to investigate intraspecific microwear differences along with tooth rows and to explore the influence of three non-dietary variables on exhibited differences: (i) tooth position, (ii) mechanical advantage, and (iii) tooth aspect ratio. Five species exhibited intraspecific microwear differences. In several crocodilians, the distally positioned teeth exhibited the ‘roughest' textures, and texture characteristics correlated with all non-dietary variables. By contrast, the mesial teeth of the roughneck monitor ( Varanus rudicollis ) exhibited the ‘roughest' textures, and texture characteristics did not correlate with aspect ratio. These results are somewhat consistent with how reptiles preferentially use their teeth during feeding. We argue that DMTA has the potential to track mechanical and behavioural differences in tooth use which should be taken into consideration in future dietary reconstructions.

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Giant lizards occupied herbivorous mammalian ecospace during the Paleogene greenhouse in Southeast Asia

et al. 2013

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Mammals dominate modern terrestrial herbivore ecosystems, whereas extant herbivorous reptiles are limited in diversity and body size. The evolution of reptile herbivory and its relationship to mammalian diversification is poorly understood with respect to climate and the roles of predation pressure and competition for food resources. Here, we describe a giant fossil acrodontan lizard recovered with a diverse mammal assemblage from the late middle Eocene Pondaung Formation of Myanmar, which provides a historical test of factors controlling body size in herbivorous squamates. We infer a predominately herbivorous feeding ecology for the new acrodontan based on dental anatomy, phylogenetic relationships and body size. Ranking body masses for Pondaung Formation vertebrates indicates that the lizard occupied a size niche among the larger herbivores and was larger than most carnivorous mammals. Paleotemperature estimates of Pondaung Formation environments based on the body size of the new lizard are approximately 2–5°C higher than modern. These results indicate that competitive exclusion and predation by mammals did not restrict body size evolution in these herbivorous squamates, and elevated temperatures relative to modern climates during the Paleogene greenhouse may have resulted in the evolution of gigantism through elevated poikilothermic metabolic rates and in response to increases in floral productivity.

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Introduction

Cited by 26 publications

References 0 publications

Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild

Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild

Dental microwear texture analysis along reptile tooth rows: complex variation with non-dietary variables

Giant lizards occupied herbivorous mammalian ecospace during the Paleogene greenhouse in Southeast Asia

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