Extreme neck elongation evolved despite strong developmental constraints in bizarre Triassic reptiles-implications for neck modularity in archosaurs.

The Triassic radiation of vertebrates saw the emergence of the modern vertebrate groups, as well as numerous extinct animals exhibiting conspicuous, unique anatomical characteristics. Among these, members of Tanystropheidae (Reptilia: Archosauromorpha) displayed cervical vertebral elongation to an extent unparalleled in any other vertebrate. Tanystropheids were exceptionally ecologically diverse and had a wide spatial and temporal distribution.

Synchrotron tomography of a stem lizard elucidates early squamate anatomy.

Squamates (lizards and snakes) include more than 10,000 living species, descended from an ancestor that diverged more than 240 million years ago from that of their closest living relative, Sphenodon. However, a deficiency of fossil evidence, combined with serious conflicts between molecular and morphological accounts of squamate phylogeny (but see ref. ), has caused uncertainty about the origins and evolutionary assembly of squamate anatomy.

The earliest-known mammaliaform fossil from Greenland sheds light on origin of mammals.

Synapsids are unique in having developed multirooted teeth and complex occlusions. These innovations evolved in at least two lineages of mammaliamorphs (Tritylodontidae and Mammaliaformes). Triassic fossils demonstrate that close to the origins of mammals, mammaliaform precursors were "experimenting" with tooth structure and function, resulting in novel patterns of occlusion.

The locomotor musculature and posture of the early dinosauriform Silesaurus opolensis provides a new look into the evolution of Dinosauromorpha.

It is widely accepted that ornithodirans (bird lineage) and some pseudosuchians (crocodilian lineage) achieved fully erect limb posture in different ways. Ornithodirans have buttress-erected hindlimbs, while some advanced pseudosuchians have pillar-erected hindlimbs. Analysis of the musculoskeletal apparatus of the early dinosauriform Silesaurus opolensis challenges this view.

Beetle-bearing coprolites possibly reveal the diet of a Late Triassic dinosauriform.

Diets of extinct animals can be difficult to analyse if no direct evidence, such as gut contents, is preserved in association with body fossils. Inclusions from coprolites (fossil faeces), however, may also reflect the diet of the host animal and become especially informative if the coprolite producer link can be established. Here we describe, based on propagation phase-contrast synchrotron microtomography (PPC-SRμCT), the contents of five morphologically similar coprolites collected from two fossil-bearing intervals from the highly fossiliferous Upper Triassic locality at Krasiejów in Silesia, Poland.

X-ray computed microtomography of Megachirella wachtleri.

Understanding the origin and early evolution of squamates has been a considerable challenge given the extremely scarce fossil record of early squamates and their poor degree of preservation. In order to overcome those limitations, we conducted high-resolution X-ray computed tomography (CT) studies on the fossil reptile Megachirella wachtleri (Middle Triassic, northern Italy), which revealed an important set of features indicating this is the oldest known fossil squamate in the world, predating the previous oldest record by ca. 75 million years.

The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps.

Modern squamates (lizards, snakes and amphisbaenians) are the world's most diverse group of tetrapods along with birds and have a long evolutionary history, with the oldest known fossils dating from the Middle Jurassic period-168 million years ago. The evolutionary origin of squamates is contentious because of several issues: (1) a fossil gap of approximately 70 million years exists between the oldest known fossils and their estimated origin; (2) limited sampling of squamates in reptile phylogenies; and (3) conflicts between morphological and molecular hypotheses regarding the origin of crown squamates. Here we shed light on these problems by using high-resolution microfocus X-ray computed tomography data from the articulated fossil reptile Megachirella wachtleri (Middle Triassic period, Italian Alps ).

Integrating developmental biology and the fossil record of reptiles.

Numerous new discoveries and new research techniques have influenced our understanding of reptile development from a palaeontological perspective. They suggest for example that transition from mineralized to leathery eggshells and from oviparity to viviparity appeared much more often in the evolution of reptiles than was previously thought. Most marine reptiles evolved from viviparous terrestrial ancestors and had probably genetic sex determination.