David J. Gower is a Merit Researcher in Herpetology and Head of the Vertebrates Division in the Department of Life Sciences at The Natural History Museum, London. A collections-based, organismal biologist with interests in a wide range of topics in natural history and evolutionary biology, he has taxon expertise in Triassic archosaurs and limbless, mostly fossorial, amphibians and reptiles. Hussam Zaher is Full Professor and Curator of Herpetology and Vertebrate Paleontology in the Museum of Zoology at the University of São Paulo. He is an evolutionary biologist focusing on the systematics, palaeontology, and comparative anatomy of reptiles, with an emphasis on the diversity and evolutionary history of snakes and other squamates.