Extreme specialization to rocky habitats inTropiduruslizards from Brazil: Trade‐offs between a fitted ecomorph and autoecology in a harsh environment

Abstract

Ecomorphological theory indicates that different ecological requirements lead to different organismal designs. Given that species with equal requirements could not coexist, traits leading to more efficient use of resources may be selected to avoid competition among closely related syntopic species, generating specialized ecomorphs. We compared habitat use, diet, thermal biology and morphology among the syntopic Tropidurus semitaeniatus, T. helenae and T. hispidus in the Caatinga of Northeastern Brazil. Tropidurus semitaeniatus and T. helenae are flattened lizards specialized to rocks and rock crevices, whereas T. hispidus has a robust body and generalist habits. We aimed to test the hypothesis that morphological modifications observed in the flattened ecomorphs are related to modifications in diet and habitat use. Also, we hypothesized that specialization to habitat induces morphological modifications, which in turn may constrain lizard performance. Flattened species differed in habitat use, morphology and prey size when compared with the generalist ecomorph. Morphological modifications were related to specializations to rocky habitats and constrained the variety of prey items consumed. This phenotype also reduced their reproductive output when compared with a robust, generalist ecomorph.

On and off the rocks: persistence and ecological diversification in a tropical Australian lizard radiation

“…Phylo-morphospace plots also suggested that the distantly related saxicoline G. borroloola / robusta and G. pamela complexes tend to have shorter toes and longer heads. Some of these phenotypic shifts, such as flattened body shape, typify rock-dwelling taxa in other lineages of Gehyra [ 14 ], other geckos [ 18 ], and other radiations of lizards [ 34 , 99 , 100 ]. However, while follow-up SURFACE and l1OU analyses identified divergent morphological regimes, they did not suggest convergence.…”

“…Species’ habitats were categorised as saxicoline (shortened to “rock”) or generalist (“gen”) following previous convention [ 14 , 34 ]. This coding captures broad distributional patterns, rather than absolute microhabitat usage rules.…”

“…1 ; Additional file 2 ), but can forage on rock surfaces in the absence of saxicoline taxa. These are referred to here as habitat ‘generalists’ following recent convention [ 14 , 34 ]. Other smaller-bodied species of Gehyra co-occur in the AMT as part of the phylogenetically distant variegata group, but these are almost entirely restricted to rocky habitats and show deep phylogeographic structure [ 35 ].…”

Reptile species composition in the Middle Gurguéia and comparison with inventories in the eastern Parnaíba River Basin, State of Piauí, Brazil

“…This argument is supported by studies that demonstrate the association of reptile species with the structure of the environment (Garden et al, 2007;Stumpel & Werf, 2012). Pelegrin et al (2017) described differences in microhabitat preferences in the Caatinga among Tropidurus hispidus, T. helenae and T. semitaeniatus, three sympatric species found in the Parque Nacional Serra da Capivara. Drymoluber brazili, Micrablepharus maximiliani and Tupinambis quadrilineatus, which were also found in other areas of Piauí, were recorded in areas with a predominance of Caatinga, Cerrado-Caatinga ecotone and Cerrado vegetation, respectively (Moura et al, 2010;Freitas et al, 2012;Silva et al, 2013).…”

Ecology and parasitism of the lizard Tropidurus jaguaribanus (Squamata: Tropiduridae) from northeastern Brazil

“…Several aspects of the ecology of species in the Tropidurus semitaeniatus Group have been studied (e.g., Kolodiuk et al 2010, Caldas et al 2015, Pelegrin et al 2017, Xavier and Dias 2017, Maia-Carneiro et al 2018. Several aspects of members of the group are phylogenetically conserved, such as specializations to live on rocks and in rock crevices, sexual dimorphism, sit-and-wait foraging, and clutch sizes of 1 or 2 eggs (with no correlation between clutch and body size).…”