Organisms comprise multiple interacting parts, but few quantitative studies have analysed multi-element systems, limiting understanding of phenotypic evolution. We investigate how disparity of vertebral morphology varies along the axial column of mammalian carnivores — a chain of 27 subunits — and the extent to which morphological variation have been structured by evolutionary constraints and locomotory adaptation. We find that lumbars and posterior thoracics exhibit high individual disparity but low serial differentiation. They are pervasively recruited into locomotory functions and exhibit relaxed evolutionary constraint. More anterior vertebrae also show signals of locomotory adaptation, but nevertheless have low individual disparity and constrained patterns of evolution, characterised by low-dimensional shape changes. Our findings demonstrate the importance of the thoracolumbar region as an innovation enabling evolutionary versatility of mammalian locomotion. Moreover, they underscore the complexity of phenotypic macroevolution of multi-element systems and that the strength of ecomorphological signal does not have a predictable influence on macroevolutionary outcomes.

Early terrestrial vertebrates (amniotes) provide a classic example of diversification following adaptive zone invasion. The initial terrestrialisation of vertebrates was closely followed by dietary diversification, as evidenced by a proliferation of craniomandibular and dental adaptations. However, morphological evolution of early amniotes has received limited study, in analyses with restricted taxonomic scope, leaving substantial questions about the dynamics of this important terrestrial radiation. We use novel analyses of discrete characters to quantify variation in evolutionary rates and constraints during diversification of the amniote feeding apparatus. We find evidence for an early burst, comprising high rates of anatomical change that decelerated through time, giving way to a background of saturated morphological evolution. Subsequent expansions of phenotypic diversity were not associated with increased evolutionary rates. Instead, variation in the mode of evolution became important, with groups representing independent origins of herbivory evolving distinctive, group-specific morphologies and thereby exploring novel character state spaces. Our findings indicate the importance of plant-animal interactions in structuring the earliest radiation of amniotes, and demonstrate the importance of variation in modes of phenotypic divergence during a major evolutionary radiation.

Macroevolution is integral to understanding the patterns of the diversification of life. As the life sciences increasingly use big data approaches, large multivariate datasets are required to test fundamental macroevolutionary hypotheses. In vertebrate evolution, large datasets have been created to quantify morphological variation, largely focusing on particular areas of the skeleton. We provide a landmarking protocol to quantify morphological variation in skeletal elements across the head, trunk, hindlimb and forelimb using 3-dimensional landmarks and semilandmarks, and present a large pan-skeletal database of bird morphology for 149 taxa across avian phylogeny using CT scan data. This large collection of 3D models and geometric morphometric data is open access and can be used in the future for new research, teaching and outreach.

The origin of herbivory in the Carboniferous was a landmark event in the evolution of terrestrial ecosystems, increasing ecological diversity in animals but also giving them greater influence on the evolution of land plants. We evaluate the effect of early vertebrate herbivory on plant evolution by comparing local species richness of plant palaeofloras with that of vertebrate herbivores and herbivore body size. Vertebrate herbivores became diverse and achieved a much greater range of body sizes across the Carboniferous–Permian transition interval. This coincides with an abrupt reduction in local plant richness that persists throughout the Permian. Time-series regression analysis supports a negative relationship of plant richness with herbivore richness but a positive relationship of plant richness with minimum herbivore body size. This is consistent with studies of present-day ecosystems in which increased diversity of smaller, more selective herbivores places greater predation pressures on plants, while a prevalence of larger bodied, less selective herbivores reduces the dominance of a few highly tolerant plant species, thereby promoting greater local richness. The diversification of herbivores across the Carboniferous–Permian boundary, along with the appearance of smaller, more selective herbivores like bolosaurid parareptiles, constrained plant diversity throughout the Permian. These findings demonstrate that the establishment of widespread vertebrate herbivory has structured plant communities since the late Palaeozoic, as expected from examination of modern ecosystems, and illustrates the potential for fossil datasets in testing palaeoecological hypotheses.

tetanurae is a special group of theropod dinosaurs that originated by the late early Jurassic. it includes several early-diverging groups of generally large-bodied predators (megalosauroids, allosauroids, tyrannosauroid coelurosaurs) as well as morphologically disparate small-bodied coelurosaurs, including birds. Aspects of the evolutionary history of tetanurans remain contested, including the topology of their deep phylogenetic divergences (among Megalosauroidea, Allosauroidea and coelurosauria). We report a new theropod, Yunyangosaurus puanensis gen. et sp. nov., based on a fragmentary specimen recovered from the Middle Jurassic Xintiangou formation of chongqing, southwestern china. it shares several features uniquely with some megalosauroids (the clade of megalosaurids + spinosaurids + piatnitzkysaurids), such as prominent rims around the anterior articular surfaces of cervical centra and bifurcated anterior dorsal neural spines (present in piatnitzkysaurids). nevertheless, it also shows several features that are rare or absent among megalosauroids and more crownward tetanurans, including prominent spinopostyzgopophyseal laminae (also present in non-tetanurans and metriacanthosaurid allosauroids), flat anterior articular surfaces of the cervical centra (also present in piatnitzkysaurids and some earlier-diverging tetanurans), and the presence of a posterior pneumatic foramen or fossa (absent in most tetanurans, but sporadically present in some cervical vertebrae of piatnitzkysaurids). Yunyangosaurus therefore presents a combination of derived and apparently primitive character states that are not seen in other theropods. this suggests that patterns of morphological evolution associated with deep tetanuran divergences were more complex than currently recognized, with implications for understanding the character evolution in theropods. The Middle and Upper Jurassic Shaximiao Formation of southwestern China has produced spectacular fossil remains of dinosaurs and many other vertebrates 1,2. Significant discoveries from this formation in the Chongqing area include the sauropods Mamenchisaurus hochuanensis, Omeisaurus changshouensis, and the theropod Yangchuanosaurus shangyouensis 3 as well as the stegosaur Chungkingosaurus jiangbeiensis 4. Compared to the