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Re-examination of the presumed Cambrian fossil fish Anatolepis reveals previous misidentification of aglaspidid sensory structures as dentine, a vertebrate sensory tissue, showing it to be an arthropod, and shifting the origin of vertebrate hard tissues to the Middle Ordovician.

Nature regulars give their recommendations for relaxed, inspiring holiday reading and viewing — from climate-change history to Isaac Newton the detective.

The Devonian fossil Tiktaalik roseae represents a transitional form between fishes and tetrapods. This paper presents a detailed examination of the braincase of this creature. Although primitive in many respects, some features nod to the tetrapod state.

A detailed description of the pectoral fin of the Devonian fish Tiktaalik roseae — a transitional form between fishes and tetrapods — gives an insight into the origins of the tetrapod limb.

The discovery of the fossil remains of a tetrapod-like fish sheds light on the order in which important tetrapod characters arose.

Hoxa- and Hoxd-deficient zebrafish generated using Crispr/Cas with fate mapping have reduced fin rays and increased endochondral elements, establishing homology between the developmental programs that create fin rays and the wrists and digits of mammals.

By comparison with modern fishes such as zebrafish, it has long seemed that the limbs of tetrapods are evolutionary innovations unique to tetrapods, but here Marcus Davis and colleagues instead studied Hox-gene expression in the development of the fins of a 'living fossil'. The paddlefish, common in the seas more than 250 million years ago, has Hox-gene patterns long considered to be tetrapod hallmarks, showing that some aspects of limb development are primitive and common to all bony fish, but which have apparently been lost in highly evolved fishes such as the zebrafish.

A new elpistostegalian from the Late Devonian period has been discovered that shows disparity in the group and represents a previously hidden ecological expansion, a secondary return to open water, near the origin of limbed vertebrates.

Palaeontologist, anatomist, explorer and artist.

Skate-specific changes in the epigenome and its three-dimensional organization contributed to the evolution of the batoid fin morphology.

Genome sequencing and phylogenomic analysis show that the lungfish, not the coelacanth, is the closest living relative of tetrapods, that coelacanth protein-coding genes are more slowly evolving than those of tetrapods and lungfish, and that the genes and regulatory elements that underwent changes during the vertebrate transition to land reflect adaptation to a new environment.

Ingo Braasch, John Postlethwait and colleagues report the genome of the spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before genome duplication. Their data provide insights into the evolution of genes involved in immunity, mineralization and development and facilitate the comparison of cis-regulatory elements between teleosts and humans.

A newly described 334-million-year-old fossil of an amphibian will give students of vertebrate evolution much to think about, for it has characters that were previously ascribed to three different types of early four-legged creature. Together with other examples, the fossil shows that during evolution new features seem to have been 'cut and pasted' on different groups at different times. Understanding such parallel evolution will require understanding the molecular and developmental basis by which such features arise.

Can we ever hope to pin down the genetic changes that underlie the big steps in evolution? Possibly so, if a study of the variation in the pelvic fins of sticklebacks is anything to go by.

The authors study the cis-regulatory evolution of the Shh locus in vertebrates. Using genomic editing and chromatin profiling, they conclude that paired fins emerged through the co-option of developmental programs for the median fins of gnathostomes.