TY - JOUR

T1 - Macroecological and biogeographical patterns of limb reduction in the world's skinks

AU - Camaiti, Marco

AU - Evans, Alistair R.

AU - Hipsley, Christy A.

AU - Hutchinson, Mark N.

AU - Meiri, Shai

AU - de Oliveira Anderson, Rodolfo

AU - Slavenko, Alex

AU - Chapple, David G.

N1 - Funding Information: We thank Reid Tingley for providing the shapefiles for the distributions of Australian skink species, and for suggesting ways to extract environmental data from them. We also wish to thank Jules Farquhar for providing extensive feedback, suggestions, and support to the improvement of the manuscript. This project was supported by the Holsworth Wildlife Research Endowment (Equity Trustees Charitable Foundation and the Ecological Society of Australia; to M.C.), the Monash‐Museums Victoria Robert Blackwood scholarship (to M.C.), an Australian Research Council Linkage Project grant (LP170100012; to D.G.C., A.R.E., and S.M.), an Australian Research Council Future Fellowship grant (FT200100108; to D.G.C.), and a Discovery Early Career Researcher Award (DECRA: DE180100629, to C.A.H.). No permits were required to carry out this research. Open access publishing facilitated by Monash University, as part of the Wiley ‐ Monash University agreement via the Council of Australian University Librarians. Publisher Copyright: © 2022 The Authors. Journal of Biogeography published by John Wiley & Sons Ltd.

PY - 2023

Y1 - 2023

N2 - Aim: Limb reduction is a dramatic evolutionary transition, yet whether it is achieved in similar trajectories across clades, and its environmental drivers, remain unclear. We investigate the macroevolutionary and biogeographical patterns of limb reduction in skinks, where limb reduction occurred more often than in any other tetrapod clade, and test their associations with substrate categories using a global database. We test for habitat associations of body shapes in a group of Australian skinks using quantitative habitat data. Location: Global (Scincidae), Australia (Sphenomorphinae). Taxon: Skinks, Australian Sphenomorphinae. Materials and Methods: We use morphological data to explore the patterns of limb reduction in the world's skinks, investigating how body proportions differ across skink clades and subfamilies. We examine the relationships between body shape and substrate (coarsely classified). Further, we investigate the relationships between body shape and high-resolution soil and climate properties extracted from each species' distribution for Australian sphenomorphines. Results: Relationships between limb lengths and trunk elongation show idiosyncratic patterns across skink clades. Presacral vertebrae numbers positively correlate with trunk elongation in all taxa, except Glaphyromorphus. Skinks from sandy habitats show greater disparity between forelimb and hindlimb lengths than all other substrate categories. In sphenomorphines, shorter limbs and elongated trunks correlate with colder, more humid microhabitats and richer soils; high limb disparity correlates with hot, arid microhabitats and sandy, poor substrates. Main Conclusions: The evolutionary trajectories of limb reduction in skinks are clade-specific and sometimes unique. Selection for specific limb proportions and body sizes in limb-reduced forms changes across substrates. On poor, sandy substrates of arid environments, body shapes with longer hindlimbs may be more efficient for locomotion in a granular fluid (i.e. sand) and exploit the air–substrate interface than complete limblessness. On richer, more humid substrates, such morphology is rare, indicating that navigating cluttered substrates selects for more equal and shorter limb lengths.

AB - Aim: Limb reduction is a dramatic evolutionary transition, yet whether it is achieved in similar trajectories across clades, and its environmental drivers, remain unclear. We investigate the macroevolutionary and biogeographical patterns of limb reduction in skinks, where limb reduction occurred more often than in any other tetrapod clade, and test their associations with substrate categories using a global database. We test for habitat associations of body shapes in a group of Australian skinks using quantitative habitat data. Location: Global (Scincidae), Australia (Sphenomorphinae). Taxon: Skinks, Australian Sphenomorphinae. Materials and Methods: We use morphological data to explore the patterns of limb reduction in the world's skinks, investigating how body proportions differ across skink clades and subfamilies. We examine the relationships between body shape and substrate (coarsely classified). Further, we investigate the relationships between body shape and high-resolution soil and climate properties extracted from each species' distribution for Australian sphenomorphines. Results: Relationships between limb lengths and trunk elongation show idiosyncratic patterns across skink clades. Presacral vertebrae numbers positively correlate with trunk elongation in all taxa, except Glaphyromorphus. Skinks from sandy habitats show greater disparity between forelimb and hindlimb lengths than all other substrate categories. In sphenomorphines, shorter limbs and elongated trunks correlate with colder, more humid microhabitats and richer soils; high limb disparity correlates with hot, arid microhabitats and sandy, poor substrates. Main Conclusions: The evolutionary trajectories of limb reduction in skinks are clade-specific and sometimes unique. Selection for specific limb proportions and body sizes in limb-reduced forms changes across substrates. On poor, sandy substrates of arid environments, body shapes with longer hindlimbs may be more efficient for locomotion in a granular fluid (i.e. sand) and exploit the air–substrate interface than complete limblessness. On richer, more humid substrates, such morphology is rare, indicating that navigating cluttered substrates selects for more equal and shorter limb lengths.

KW - Australian Sphenomorphinae

KW - biogeography

KW - ecomorphology

KW - limb reduction

KW - macroecology

KW - morphological evolution

KW - skinks

U2 - 10.1111/jbi.14547

DO - 10.1111/jbi.14547

M3 - Journal article

AN - SCOPUS:85144021117

VL - 50

JO - Journal of Biogeography

JF - Journal of Biogeography

SN - 0305-0270

IS - 2

ER -