The origin and early evolution of snakes has long been studied, but little research has focused on soft-tissue organs such as the brain. I report data from dissections and 3D reconstructions of the endocasts of diverse species, including the Cretaceous stem snake Dinilysia patagonica in order to provide a comparative evolutionary framework for the snake brain. Snakes are a special case among reptiles because the braincase almost entirely encloses the whole brain, so endocasts provide realistic representations of brain size and shape. Diversity of brain gross anatomy among snakes is remarkable, encompassing two major cerebrotypes occurring in surface-dwelling and burrowing species. The repeated acquisition of the burrowing cerebrotype in different and phylogenetically distant snake clades suggests that brain gross anatomy is surprisingly evolutionary labile in snakes. Brain gross anatomy and other features such as body size and the absence of any unequivocal osteological feature related to burrowing is interpreted as evidence that D. patagonica was surface-dwelling, and that at least some of the early history of snakes occurred above ground.

We give a review of all published Palaeogene snake taxa from all localities worldwide. Several conceptual and material advances in the past two decades—a focus on apomo+P31rphies, greater attention to variation, quantification of morphology, and new fossil discoveries—have vivified the fossil record. Particularly noteworthy have been new fossils from Gondwanan continents and complete, articulated skeletons. Species known only from vertebrae are unlikely to be placed precisely phylogenetically, but a high number of vertebrae is a strong indication that cranial remains are present, which in turn allow more precise phylogenetic placement. Extrapolations of snake palaeodiversity are of the same order of magnitude as rough calculations of cumulative lineage diversity in the Palaeogene, raising the prospect that palaeontological morphospecies may more closely approximate biological species than is commonly conceived. As their interrelationships become better known, Palaeogene fossils will increasingly help elucidate the early evolution of snakes.

This brief chapter introduces the book. The rationale, scope, and coverage are summarized, including mention of topics that are not covered. Aspects of debate, disagreement, and consensus in the field are summarized before the chapter is concluded with a look to future potential progress.

The Cretaceous fossil record of snakes demonstrates the origin and evolution of the snake body and the early ecological and biogeographic history of the clade during the first 80 million years of their history. Consisting primarily of isolated vertebrae as well as a small number of mostly complete specimens, the record shows the elongate body of snakes evolved no earlier than approximately 100 million years ago. Stem snakes are present in terrestrial and marine palaeoenvironments throughout the Late Cretaceous of northern and southern continents. Conversely, the oldest records of living clades are restricted to the Campanian of South America, Africa, and possibly North America, which requires episodes of dispersal, or unrealistically long ghost lineages extending back to tectonically-mediated vicariance, to explain geographic distributions. Most Maastrichtian-aged stem and primary living clades extend into the Paleogene, indicating that the K-Pg extinction event had little visible effect on the evolution of snakes, whereas major diversifications of crown clades are constrained from middle Paleogene to Neogene.

Snakes have distinct body plans that can be traced to the origin of the clade. It remains unresolved whether ancestral snakes were adapted to terrestrial environments as burrowers, or to marine environments as swimmers. Recently, new approaches have been used to infer fossorial and aquatic specialists in the early evolution of snakes, using virtual CT models of the ear of fossils. This chapter reviews variation in the osseous part of the ear of major snake lineages. Vestibules are relatively large in fossorial species and small in aquatic snakes. Using quantitative analyses of bony labyrinth geometry, it has been suggested that putative stem snakes, such as Dinilysia patagonica, were fossorial. Improvements to testing correlations between bony labyrinth morphology and ecology can be made in the refinement of quantitative approaches to capturing and analysing shape variations, as well as better classifications of ecology. Using inner and middle ear morphology to improve the accuracy and precision of inferences of the ecology of the ancestral snake will depend also upon robust, well-resolved phylogenies for extinct and extant taxa, and denser taxonomic and ecomorphological sampling.

Squamata, the group that comprises lizards, snakes, and amphisbaenians, is the largest and most diverse major group of living reptiles. Although most recent estimates place their divergence from Rhynchocephalia in the early Triassic, the first unequivocal records of squamates currently date from the Middle Jurassic, and the first crown squamates, representing Scincoidea, Anguimorpha, and possibly Gekkota, are known from the Late Jurassic. The record then improves substantially in the Early Cretaceous, with squamate fossils recorded from most major continents and showing evidence of expansion into a diversity of specialist niches. Despite recent claims to the contrary, the earliest unequivocal snake fossils also date from this period, with fragmentary remains from the Aptian-Cenomanian of North Africa and North America, followed by a more substantial global record from the Cenomanian onwards. The re-interpretation of the Middle Jurassic to Early Cretaceous parviraptorids as snakes was based on a misinterpretation of the original material, as shown by new associated specimens from the Middle Jurassic of Scotland.

This summarises Fallon’s contributions to the study of the cultural history of dinosaurs, literature and science, the popularisation of science, and transatlantic literary culture. It notes areas of potential future value for scholars interested in the importance and meaning of the dinosaur both in transatlantic culture and globally, including overlooked historical figures, before considering dinosaurs today and how they continue to be reimagined in both specialist palaeontology and popular culture. Fallon (1) summarises a drastic 2017 revision of the dinosaur family tree in Nature in which Victorian terms are simultaneously overridden and revived; (2) notes that Too Big to Walk, a 2018 book by independent researcher Brian Ford, presents a modern attempt to use dinosaurs to contradict the authority of elite science; (3) highlights the popularity of the Jurassic World film franchise, which in its first two films ignores the largely Chinese research that has drastically changed scientists’ conceptions of dinosaurs since the 1993 original Jurassic Park; and (4) looks at the Smithsonian Museum’s Hall of Fossils, which recruits dinosaurs into a narrative about climate change.

This introduction sketches a cultural history of dinosaur palaeontology in the nineteenth and early twentieth centuries, indicating how the book addresses the lack of literary work on the understanding of dinosaurs in this period. While dinosaurs were a British area of science in the first half of the nineteenth century, American palaeontologists took clear pre-eminence in this field from the 1870s. American research transformed dinosaurs from giant lizards into a far stranger and more heterogenous group. Fallon argues that literary scholars have not yet grappled with this cultural shift in perceptions of the dinosaurs, an omission made all the more striking by the fact that it was during the decades around 1900 that ‘dinosaur’ first became a household word. Built into this word were important ideas about imperialism, progress, romance, and the practice of science. Fallon explains how exploring this subject provides wider insights into the relationships between literature and science and between popular and specialist science writers, in addition to its value as a case study on the transatlantic nature of literary media at the end of the nineteenth century.

Chapter 4 shows dinosaurs’ link to concerns about secularisation and specialisation contributed to Arthur Conan Doyle’s famous romance The Lost World. It argues that the text can be understood in relation to Conan Doyle’s romantic approach to scientific knowledge, especially his strident anti-materialism and aversion to technical jargon. Examining archival material from New York Public Library’s Berg Collection, including the original manuscript, Fallon weaves the content of The Lost World together in surprising ways with Conan Doyle’s palaeontological forays, cryptozoological sightings, and interest in psychical research, showing that noting the differences between the US and UK serialised and book versions provides a more precise understanding of Conan Doyle’s intended romantic effects. In particular, Fallon emphasises the illustrations by Conan Doyle’s brother-in-law, Patrick Forbes. Alongside the text, these subtle and meticulously planned images make clear the author’s desire to convince readers that the world is full of unexplained wonders. As such, the British book edition in which Forbes’s images appear was, for Conan Doyle, the correct way to experience The Lost World.

Chapter 2 explores a range of fictional and non-fictional writing on dinosaurs. The first half shows how different writers, including Henry Neville Hutchinson, Grant Allen, and geoscientist Henry Woodward, invoked the comic monsters of Lewis Carroll to develop a new, ‘grotesque’ register for describing dinosaurs. This language naturalised an emergent understanding of dinosaurs, especially American dinosaurs like Triceratops, as having gone extinct owing to the evolution of uselessly monstrous characteristics. These ideas were appealingly absurd to general audiences, who could contrast the progressive traits and intelligence of mammals like themselves with the doomed grotesqueness of the dinosaurs. The chapter’s second half examines this new way of talking about dinosaurs, providing close readings of humourist Eugene Field’s poem ‘Extinct Monsters’ (1893), Edward Cuming’s Wonders in Monsterland (1901), and Emily Bray’s Old Time and the Boy (1921). In addition to depicting dinosaurs through Carrollian nonsense conventions, all three of these texts were direct responses to the works of Hutchinson, demonstrating his long-term importance for the popularisation of dinosaurs.

Chapter one provides a case study of Henry Neville Hutchinson, a frequently overlooked figure who was not only the most important early populariser of American dinosaurs but also a proponent of using imaginative literature to widen the mass public’s access to science. An unbeneficed British clergyman without a formal scientific position, Hutchinson aired his views both in popular journalism and in books on palaeontology like Extinct Monsters (1892). His writings often contradicted the views of palaeontological authorities. This chapter argues that palaeontologists who read Hutchinson’s democratising works with concern responded by fashioning clearer distinctions between true science and work that was popularisation or romance. In 1894 British palaeontologist Harry Seeley described Hutchinson’s writing as ‘literature rather than science’. As Fallon demonstrates, Seeley’s response also undermined Hutchinson’s popularisation of the previously obscure word ‘dinosaur’, which Seeley believed to be a misleading term wrongly emphasised by American researchers. Subsequently, Fallon shows how Hutchinson’s controversial attempt to publish a paper on the American dinosaur Diplodocus for the specialist Geological Magazine led him to criticise the secularity and complex style of conventional scientific articles. Hutchinson’s career exemplifies the concerns of this book.

The book sets today's defaunation event into its historical setting. The best source of information available to do that is the fossil record. Unfortunately, the fossil record has some inbuilt limitations that affect any analysis that uses it. This chapter starts by outlining these limitations and what we can do limit them. I then look at how the extinction and origination (evolutionary appearance) of species are recorded in the fossil record. This is important as the pattern of extinction and origination of species over deep time forms the basis of the geological time scale that is used throughout the book. Finally, I examine the beginnings of modern extinction studies and the recognition of the Big Five mass extinctions.