PALAEONTOLOGY[online]

May12014

Fossil Focus: Arthropod–plant interactions

Fossil Focus

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...

Apr12014

Fossil Focus: Eggs, nests and dinosaur reproduction

Fossil Focus

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...

Mar12014

Patterns in Palaeontology: The latitudinal biodiversity gradient

Patterns in Palaeontology

by Philip D. Mannion*1 Introduction: Today, most living species are found in the tropics, the region of the Earth that surrounds the Equator. Species numbers, a measure of biodiversity, decline towards both the North and South poles (Fig. 1). This is known as the latitudinal biodiversity gradient (LBG), and it is the dominant ecological pattern on Earth today. Although there are exceptions to the rule, including high-latitude peaks in diversity of many marine or coastal vertebrates (including seals and albatrosses), the LBG describes the distribution of species diversity for the vast majority of animals and plants, both on land and in the sea, and in the Northern and Southern hemispheres. Understanding the causes and evolution of the LBG helps researchers to explain present-day geograp...

Feb12014

Life as a Palaeontologist: Palaeontology for dummies, Part 2

Life as a Palaeontologist

by Russell Garwood*1 Introduction In Palaeontology for Dummies, Part 1, we looked at modern palaeontology as a discipline, including the broad range of specialisms in the field. I hope it convinced you that palaeontology is an exciting and ever-expanding subject. Here, in the second part, we will focus on the birth and historical development of palaeontology, which has at times been highly controversial. We’ll first consider how humans and fossils interacted before science was formalized, then we will move on to the birth of palaeontology during the Enlightenment era in the seventeenth and eighteenth centuries. We will cover the field’s expansion and rapid development during the nineteenth century, and finish with a few of the most notable findings trends in the past century. For sake...

Jan12014

Patterns In Palaeontology: Trends of body-size evolution in the fossil record – a growing field

Patterns in Palaeontology

by Mark A. Bell*1 Introduction: The body size of an animal is often considered the most important part of its biology. Large body size brings many advantages, which can include better ability to capture prey, success in evading predators, intelligence, longevity and reproductive success; it also makes a greater range of resources available. A larger animal has a lower surface area to volume ratio than a smaller animal, which results in less heat loss to the surroundings, allowing it to remain warmer for longer in a cold environment. However, one major disadvantage is that larger organisms are, in general, more specialized, and can require more food for example. This can put species at higher risk of extinction caused by rapid environmental change. Since the work of nineteenth-century ...

Dec12013

Life as a palaeontologist: Palaeontology for dummies, Part 1

Life as a Palaeontologist

by Russell Garwood *1 pa·lae·on·tol·o·gy / pa·le·on·tol·o·gy noun /ˌpælɪɒnˈtɒlədʒi/ or /ˌpeɪlɪɒnˈtɒlədʒi/ — The scientific study of prehistoric life. Introduction Palaeontology. If you’re reading this, it is likely that you’ve already encountered this particular corner of the scientific world, and know what it involves. If not, welcome: I think palaeontology is awesome and I hope that by the end of this article, you will too. Either way, it never hurts to define terms. As the above definition says, palaeontology is the study of prehistoric life. The discipline is actually rather wide ranging, with many sub-disciplines, but it is fair to say that most forms encompass the study of fossils or their traces. This study allows us to better understand extinct organisms’ biology, evolutionary...

Nov12013

Fossil Focus: Heterostraci

Fossil Focus

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...

Oct12013

Patterns in palaeontology: An introduction to ancient DNA

Patterns in Palaeontology

By Peter D. Heintzman*1 Introduction: Deoxyribonucleic acid, or DNA for short, is the magical molecule that encodes instructions on how to build organisms, and has been doing so successfully for at least the past 2.5 billion years. Although its function has remained constant throughout this time, the instructions themselves have been slowly modified and upgraded to cope with the changing demands of organisms and the environments in which they live. A modification to DNA is called a mutation, and it is through mutations that we are able to track how organisms have changed, or evolved, through time. In all multicellular organisms, there are two major types of DNA: mitochondrial (mtDNA) and nuclear (nuDNA) (Fig. 1). These have different histories and can therefore tell us different thing...

Sep12013

Fossil Focus: Encephalized bipedal apes

Fossil Focus

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...

Aug12013

Patterns in Palaeontology: Why the thunder lizard was really the deceptive lizard.

Patterns in Palaeontology

by Chloe Marquart1 When I tell the average stranger that I'm a palaeontologist, the first question that I'm inevitably asked is: "Like Ross from Friends?" The second is: "Have you named any dinosaurs?" The naming of fossils is actually a very small part of the work that palaeontologists do, but it often garners the most attention from the press and public. It can be difficult for people to understand how scientists can suddenly decide that a well-known, often iconic name has never 'existed' - in a scientific sense, at least. Many grown adults still mourn the loss of their beloved Brontosaurus (more on him later), and in the past few years, campaigns were begun to ‘Save Triceratops’ when it was declared that this dinosaur and Torosaurus might be the same animal (Fig. 2). Although...