by Stephen F. Poropat*1,2 Introduction: Ask the average person in the street to name an Australian dinosaur, and you will be lucky if you get a correct answer. If they say crocodile, they are in the right postcode but have the wrong address. If they say emu, then they are correct, strictly speaking, but they are either lucky or being smart. If they say kangaroo, back away slowly and avoid eye contact. If they say koala bear, run home and take a few Panadol. I could forgive most people for not being able to identify any Australian dinosaurs. First and foremost, there are not many to know: only 18 Australian dinosaurs (including one bird, Nanantius) from the Mesozoic era (251 million to 66 million years ago) have been officially named. And yet, the first discovery of Mesozoic dinosaur r...
by Dave Hone(1) Introduction: Thanks to Tyrannosaurus rex, the tyrannosaurs are among the most famous of the extinct dinosaur groups. They receive a disproportionate amount of attention in the media and hold a firm place in the public imagination. However, this also means that more misconceptions and out-of-date ideas are promoted for this group than any other, and the excess of attention detracts from the fact that they are a genuinely interesting clade of animals. In fact, thanks to a great deal of research effort, we may know more about tyrannosaurs than any other group of dinosaurs from the Mesozoic era (252 million to 66 million years ago). This alone makes them a key part of palaeontology. All tyrannosaurs were carnivores, and although the most famous forms from the last part o...
by Luke Parry*1 Introduction: Annelids, whose name comes from the Latin meaning ‘little ring’, make up a phylum of invertebrates with a unique segmented body plan. They are important components of terrestrial and marine ecosystems, and form one of the most diverse invertebrate groups, including as many as 15,000 described species (Fig. 1). Their closest living relatives are the molluscs, brachiopods and nemerteans (proboscis worms). Annelids can broadly be split into two groups, the polychaetes and clitellates. These groups share many features, such as segmented bodies and paired bundles of bristles made of chitin, called chaetae or setae. The most familiar annelids are the clitellates — the earthworms, leeches and their relatives — which have become adapted to a terrestrial lifestyle
by Rachel A. Racicot*1 Introduction Porpoises are among the smallest of modern whales, but they are one of the most amazing groups. They use specialized high-frequency hearing and sound production, and they have one of the best fossil records of any marine mammal. Thanks to modern imaging technology, we have been able to learn about how porpoises are able to sense their environment through echolocation and how they evolved. I will be telling you a bit about a particularly interesting porpoise from the fossil record, Semirostrum ceruttii (‘Cerutti’s half-nose’), and using it as an example of how CT scans help scientists to explore ancient and modern anatomy. What are porpoises? People sometimes use ‘porpoise’ interchangeably with ‘dolphin’, but scientists use the term to refer to a dist
by Jennifer Anné*1 Introduction Palaeopathology is the study of the disease and repair of ancient life — most commonly in bone. First coined for the study of diseases in Egyptian mummies, the term was adopted to cover fossil material in 1917 by the first dinosaur doctor, Roy L. Moodie, but has become popular only in recent decades. It is surprising that the study of palaeopathology in the fossil record took so long to catch on in palaeontology. Part of the problem lies with difficulty in getting hold of specimens or accessing the techniques and equipment needed for sensitive analysis. But even if all those problems have been overcome, diagnosing a fossil pathology beyond a vague description brings its own challenges. Difficulties with diagnosing Palaeopathologies may be fairly easy for
by James M. Neenan1 Introduction: The placodonts were a group of marine reptiles that lived in shallow coastal waters, and mostly ate hard-shelled prey such as mussels and other bivalves (that is, they were durophagous). They lived during the Triassic period, and have so far been found in modern-day Europe, the Mediterranean and South China (Fig. 1). The Triassic was a very special time for marine-reptile evolution, with their greatest morphological diversity being known from this period. The beginning of the Triassic was characterized by the largest mass-extinction event that has ever occurred on Earth (the Permian–Triassic extinction), in which around 95% of all marine life went extinct. This marked the start of the Mesozoic era (the ‘age of dinosaurs’ that contains the Triassic, Juras
by Ben J. Slater*1 Introduction: When the geneticist and evolutionary biologist J. B. S. Haldane was asked what he could conclude about the nature of a creator from his studies of natural history, he supposedly replied that any creator must have “an inordinate fondness for beetles”. Indeed, there are more species of beetle than of any other animal alive today, and as insects, beetles belong to the most diverse class of modern organisms, which includes more than two-thirds of all described species (Fig. 1). It can be said that macroscopic life is dominated by insects (and in particular beetles), but like all organisms, insects — and other arthropods, the larger phylum to which the insects belong — don’t exist in isolation. Organisms are the product of their environment, which inc
by Bernat Vila1 Introduction Of all the dinosaur fossils, skeletons are most fascinating to the public, because they represent real evidence of dinosaurs’ existence. When the study of skeletons is combined with information from fossilized footprints (which show how and how fast dinosaurs walked), dinosaurs seem to come to life: the body seems to move and interact with the substrate. But in real life, dinosaurs lived in similar ways to modern animals, and by asking the proper questions of some singular fossils, researchers can find out about their biology, such as their feeding strategies, growth and reproduction. Fossil eggs and nests are the only evidence about the reproductive biology of dinosaurs. The study of oological fossils Eggs and nests are called indirect fossils because they
by Joseph N. Keating*1 Introduction: The Heterostraci (which means ‘different shield’) make up an extinct group of jawless fish that lived during the early to middle Palaeozoic era, approximately 440 million to 359 million years ago. They were exceptionally diverse, with over 300 species currently described from marine and freshwater sediments of North America, Europe and Siberia. Heterostracans are characterized by their external armour of distinct plates, which are composed mainly of bone and dentine (a hard-tissue component of teeth in vertebrates). Most heterostracans can be classified into two major groups, the cyathaspids and the pteraspids, which differ with respect to the structure, number and arrangement of their armoured plates. Heterostracan fossils are rarely found as comp
by Holly M. Dunsworth Humans would not have evolved if the ancestors of the African great apes had not. The ape fossil record begins 23 million years ago with the earliest putative apes, including Morotopithecus and Proconsul (Figure 1), from sites in East Africa, followed by many others throughout Africa, Europe and Asia. Although this record is fairly rich, it has done no better than DNA-based estimates at helping researchers to determine how living apes are related. Genetic studies estimate that gorillas split off from other apes about 9 million to 8 million years ago, and that the ancestors of bonobos and chimpanzees began evolving separately from the ancestors of humans 7 million to 6 million years ago. Comparative anatomy, physiology, behaviour and genetics provide enough e...