Paleontology

eLife assessment

This paper describes the anatomy of important fossil remains of the dwarf dinosaur Europasaurus, providing compelling evidence for precociality. Only a handful of papers provide detailed information on sauropod neuroanatomy - as such this paper will be of interest to a relatively wide range of researchers, in particular vertebrate palaeontologists, and comparative anatomists.

eLife assessment

Most birds today can lift the upper beak independently of the brain case, enabled by a series of mobile joints and bending zones in the skull. The computed tomography of the skull of a 120-million-year-old toothed bird produced by the authors shows for the first time that the joints were still absent, but also hints at how they may have evolved later. This compelling, important paper is of high interest to evolutionary biologists, vertebrate paleontologists (especially, but by no means only, those working on bird origins) and specialists in biomechanics.

Evaluation Summary:

The Cretaceous dinosaur Spinosaurus has recently drawn significant attention as it was hypothesized to be the first aquatic dinosaur, using tail-powered swimming in surface waters and at depth. In a reappraisal of the "aquatic hypothesis", new lines of evidence – including the CT-based skeletal restoration of Spinosaurus and biomechanical tests – support the alternative "semi-aquatic hypothesis". This article will be of interest to vertebrate paleontologists and functional morphologists, as well as wider academic and non-academic audiences.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1, Reviewer #2 and Reviewer #3 agreed to share their name with the authors.)

Evaluation Summary:

Clement and colleagues describe and illustrate the endocasts of six Palaeozoic lungfish genera from superb 3D fossil material, which are very informative for the understanding of brain evolution of lungfishes, the extant sister group to land vertebrates. Rendering important anatomical details regarding brain evolution in lungfishes, and sarcopterygians in general, this work will be of broad interest to zoologists, including vertebrate paleontologists and neuroanatomists.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #, Reviewer #2 and Reviewer #3 agreed to share their name with the authors.)

Evaluation Summary:

This article will be of interest to paleobiologists studying the evolution of avian diets and/or prehistoric ecosystem dynamics. The study uses an exceptional new specimen of an early diverging stem bird with a near-complete skull, to reassess diet in the taxon and explore possible early mechanisms for bird-mediated seed dispersal. The claim for frugivory is currently insufficiently supported.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 and Reviewer #3 agreed to share their name with the authors.)

Evaluation Summary:

Using micro-CT approaches, the authors provide a thorough investigation of dental morphology and development in some of the rarest and earliest representatives of three early ceratopsian dinosaur genera from China. The innovative approaches employed and nuanced inferences, including about the dental anatomy and replacement patterns in these early-diverging ceratopsians, make the manuscript interesting to mainstream researchers as well as the public.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 and Reviewer #2 agreed to share their names with the authors.)

Evaluation Summary:

This paper reports a new species of armored dinosaur from rocks in southwestern China dated to the beginning of the Jurassic Period. This represents the first valid species of armored dinosaur from the Early Jurassic in Asia, as although the presence of armored dinosaurs in Asia has been documented for decades based on isolated jaw bones referred to Thyreophora-the group of armored dinosaurs-none that material was complete enough for diagnosis to a known or new species. This new specimen demonstrates the rapid diversification and distribution of armored dinosaurs across the northern hemisphere early in their evolutionary history.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 and Reviewer #2 agreed to share their name with the authors.)

Evaluation Summary:

The study proposes a new evolutionary-ecological scenario for Late Paleozoic and early Mesozoic beetles, supported by the summary of all available knowledge about early beetle fossils, including analyses of their taxon and morphological diversity and phylogenetic relationships. The effects of xylophagous beetles during the Paleozoic may have played a fundamental role in global biochemical cycles. The results advance our understanding of the evolutionary success of beetles and the many ways in which large environmental changes may affect biodiversity in general.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 agreed to share their name with the authors.)

Evaluation Summary:

This paper is a very valuable contribution to paleoanthropology especially to those who study the evolution of human posture and locomotion. Overall, the quality of some of the fossils is unusually high for this chronology, and the data are properly presented and analysed. However, the authors should be more cautious in their interpretation of the data which does not fully support their conclusions.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 agreed to share their name with the authors.)

Evaluation Summary:

This paper will be of interest to readers in the field of plant evolutionary biology and paleontology, paleobotany in particular. Using novel 3D reconstruction techniques, the authors provide the first evidence-based reconstruction of Asteroxylon mackiei, the Early Devonian Rhynie chert plant known for a century, and demonstrate that it possessed an extinct pattern of root development transitional to the evolution of true roots in modern club-mosses. The use of multiple lines of evidence and 3D reconstructions based on serial sections of petrified materials provides compelling support for the key conclusions of the paper.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewers #1, #2, and #3 agreed to share their names with the authors.)