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The skull anatomy of amphisbaenians directly influences their capacity to burrow and is crucial for the study of their systematics, which ultimately contributes to our comprehension of their evolution and ecology. In this study, we employed three-dimensional X-ray computed tomography to provide a detailed description and comprehensive comparison of the skull anatomy of two amphisbaenian species with similar external morphology, Amphisbaena arda and Amphisbaena vermicularis. Our findings revealed some differences between the species, especially in the sagittal crest of the parietal bone, the ascendant process, and the transverse occipital crest of the occipital complex. We also found intraspecific variation within A. vermicularis, with some specimens displaying morphology that differed from their conspecifics but not from A. arda. The observed intraspecific variation within A. vermicularis cannot be attributed to soil features because all specimens came from the same locality. Specimen size and soil type may play a role in the observed differences between A. arda and A. vermicularis, as the single A. arda specimen is the largest of our sample and soil type and texture differ between the collection sites of the two species., The skull anatomy of amphisbaenians directly influences their capacity to burrow and is crucial for the study of their systematics, which ultimately contributes to our comprehension of their evolution and ecology. In this study, we employed three-dimensional X-ray computed tomography to provide a detailed description and comprehensive comparison of the skull anatomy of two amphisbaenian species with similar external morphology, Amphisbaena arda and Amphisbaena vermicularis. Our findings revealed some differences between the species, especially in the sagittal crest of the parietal bone, the ascendant process, and the transverse occipital crest of the occipital complex. We also found intraspecific variation within A. vermicularis, with some specimens displaying morphology that differed from their conspecifics but not from A. arda. The observed intraspecific variation within A. vermicularis cannot be attributed to soil features because all specimens came from the same locality. Specimen size and soil type may play a role in the observed differences between A. arda and A. vermicularis, as the single A. arda specimen is the largest of our sample and soil type and texture differ between the collection sites of the two species.

In 2023, researchers from around the world entered the BMC Ecology and Evolution photography competition. As a result, we received a spectacular collection of photographs that capture the wonder of nature, those looking to understand it and glimpses into long lost worlds. This editorial celebrates the winning images selected by the Editor of BMC Ecology and Evolution and senior members of the journal’s editorial board.

The inner ear labyrinth is an organ able to perceive balance and spatial orientation, but the drivers of its morphological variation across and within vertebrate lineages are unclear. We assess two competing hypotheses whether this organ, and specifically the semicircular canals, modifies its shape as a functional adaptation to ecology and locomotion, or according to the constraints of skull morphology. We test these using 52 species of Australian sphenomorphines, a group of scincid lizards that evolved changes in body shape and locomotory adaptations to fossoriality multiple times independently, by reducing their limbs. We find a correlation between semicircular canal shape and degree of limb reduction in these lizards, supporting a functional hypothesis. The interaction between body shape and substrate ecology is also a significant predictor. The wider and more eccentric semicircular canals of limb-reduced skinks indicate higher balance sensitivity and manoeuvrability compared with fully limbed skinks, probably as an adaptation to navigating cluttered environments. Conversely, our results show only a minimal influence of skull constraints on semicircular canal shape, having instead significant effects on size. This supports the hypothesis that in these skinks inner ear shape evolution is driven by specific locomotory strategies more than it is constrained by cranial anatomy., The inner ear labyrinth is an organ able to perceive balance and spatial orientation, but the drivers of its morphological variation across and within vertebrate lineages are unclear. We assess two competing hypotheses whether this organ, and specifically the semicircular canals, modifies its shape as a functional adaptation to ecology and locomotion, or according to the constraints of skull morphology. We test these using 52 species of Australian sphenomorphines, a group of scincid lizards that evolved changes in body shape and locomotory adaptations to fossoriality multiple times independently, by reducing their limbs. We find a correlation between semicircular canal shape and degree of limb reduction in these lizards, supporting a functional hypothesis. The interaction between body shape and substrate ecology is also a significant predictor. The wider and more eccentric semicircular canals of limb-reduced skinks indicate higher balance sensitivity and manoeuvrability compared with fully limbed skinks, probably as an adaptation to navigating cluttered environments. Conversely, our results show only a minimal influence of skull constraints on semicircular canal shape, having instead significant effects on size. This supports the hypothesis that in these skinks inner ear shape evolution is driven by specific locomotory strategies more than it is constrained by cranial anatomy.

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

In 2022, researchers from around the world entered the BMC Ecology and Evolution photography competition. The contest produced a spectacular collection of photographs that capture the wonder of the natural world and the growing need to protect it as the human impact on the planet intensifies. This editorial celebrates the winning images selected by the Editor of BMC Ecology and Evolution and senior members of the journal’s editorial board.

The Quaternary Period is characterized by dramatic global climatic changes. Quaternary fossil deposits, which can offer excellent stratigraphic resolution, provide a unique opportunity to understand how fauna respond to past environmental change. Here, we test if the herpetofauna of McEachern’s Deathtrap Cave, a late Pleistocene to Holocene pitfall trap deposit from Victoria, Australia, shows climate-related shifts in taxonomic relative abundance through time. During the last 14,000 years, southeastern Australia experienced pronounced periods of aridity, while temperatures remained relatively stable. We show that the stratigraphic layers of this deposit are characterized by different relative abundances of reptile subfamilies, and that changes in subfamily abundance between layers correlate with known shifts to aridity, based on the percentage of C4 grasses present in the region. We further identify 13 lizard morphotypes from the fossil deposit and compare this diversity with the present-day lizard fauna. Our analyses indicate that gradual changes in community structure, which are typically observed in southeastern Australian vertebrate communities during the Pleistocene–Holocene transition, can partly be explained by changing aridity. These findings represent an important contribution to understanding Quaternary community change in Australia, particularly because evidence of faunal succession of reptile and amphibian communities in Victoria is lacking. Our results further demonstrate the utility of the Australian herpetofaunal fossil record for detecting community responses to past climate change on relatively shallow timescales and at higher levels of taxonomic identification.