Fossil Focus

Fossil Focus: Diploporitans

Fossil Focus: Diploporitans

Fossil Focus
by Sarah L. Sheffield*1 Introduction: Echinoderms, a group of marine animals that includes familiar organisms such as sea stars and sea urchins, were much more diverse in the past than they are today. There are five living classes of echinoderms (sea stars, sea urchins, brittle stars, sea cucumbers and crinoids), but more than 20 extinct classes are known only from the fossil record. During the Palaeozoic Era (542 million to 251 million years ago), especially, echinoderms were incredibly diverse and thrived all over the globe (Fig. 1). This was a time of significant environmental change, with the climate ranging from very warm oceans with high sea levels and high atmospheric carbon dioxide concentrations to much colder oceans, with extensive glacial ice. By studying how fossil ...
Fossil Focus: Calcareous nannofossils: the best things are microscopic

Fossil Focus: Calcareous nannofossils: the best things are microscopic

Fossil Focus
by Amy P. Jones1 Introduction: Calcareous nannofossils — words that are, perhaps, unfamiliar to you. You might never have stumbled upon them before … So what are they? They are the fossil remains of coccolithophores: single-celled marine algae from the phylum Haptophyta and division Prymnesiophyceae. They exist in great abundance around the world in the oceans, and have done for over 200 million years. They are also known as the grass of the sea, and are regarded as one of the most important phytoplankton groups in the oceans owing to their relationship with the carbon cycle. They provide valuable proxies to help us understand conditions throughout geological history, because their evolution shows consistent and resilient patterns. Nannofossils are composed of calcium carbonate, also
Fossil Focus: Paracrinoids

Fossil Focus: Paracrinoids

Fossil Focus
by Maggie R. Limbeck*1 Introduction: The oceans of the Palaeozoic era (541 million to 252 million years ago) were full of animals that we are familiar with, such as fish, snails, and coral, but also included many organisms that look almost nothing like their living relatives. The further back in time we go, for instance to the Cambrian and Ordovician periods (541 million to 444 million years ago), the greater the difference in body plans, or morphologies, compared to modern species. Echinoderms are an excellent example of this — living members of the group, such as starfish and sea urchins, are easily recognizable, but many of their extinct, fossilized relatives from hundreds of millions of years ago look very different. Understanding these different body forms is important to palaeontol
Fossil Focus: Blastoids

Fossil Focus: Blastoids

Fossil Focus
by Jennifer E. Bauer*1 Introduction: The ancient seas of the Palaeozoic era (541 million to 252 million years ago) teemed with unusual creatures that would be almost unrecognizable to us today. Although these animals look very peculiar, they often have living relatives that we are more familiar with. Consider echinoderms, such as sea stars and sea urchins: these marine animals can be recognized easily by scientists and the general public alike due to their distinctive five-fold symmetry and often vibrant colours. However, the Palaeozoic fossil record of echinoderms includes a wide range of forms that are radically different from living species. Indeed, there are only 5 major living groups of echinoderms, but about 20 extinct groups known only from the Palaeozoic. This means that the foss
Fossil Focus: Coleoid cephalopods – the squid, cuttlefish and octopus

Fossil Focus: Coleoid cephalopods – the squid, cuttlefish and octopus

Fossil Focus
by Thomas Clements*1 What are coleoids? The coleoid cephalopods (Fig. 1), squids, cuttlefish and octopuses2, are an extremely diverse group of molluscs that inhabits every ocean on the planet. Ranging from the tiny but highly venomous blue-ringed octopus (Hapalochlaena) to the largest invertebrates on the planet, the giant and colossal squids (Architeuthis and Mesonychoteuthis respectively), coleoids are the dominant cephalopods in modern oceans. For humans, they are a vital dietary and economic resource and have an important role in our culture. Cephalopods have intrigued and been revered by humans from ancient times and, more recently, during the nineteenth and twentieth centuries, they became part of pop-culture. Stories of gargantuan poulpes attacking the submarine ‘Nautilus’ in Jule
Fossil Focus: Thalattosuchia

Fossil Focus: Thalattosuchia

Fossil Focus
by Mark T. Young*1, Sven Sachs2 & Pascal Abel3 Introduction: To most people, crocodilians are large-bodied carnivores that have been unchanged since the age of the dinosaurs. However, during their 230 million-year history, modern crocodilians and their extinct relatives evolved a stunning diversity of body plans, with many looking very different from those alive today (crocodiles, alligators, caimans and gharials). The first crocodylomorphs (the term used for living crocs and various fossil groups) are known from the Late Triassic Period, approximately 235 million to 237 million years ago. These animals lived on land and looked much more like a greyhound than a crocodile, with long legs and a skull that was deep like that of a meat-eating dinosaur, rather than flattened like that
Fossil Focus: Reimagining fossil cats

Fossil Focus: Reimagining fossil cats

Fossil Focus
by Andrew Cuff*1 Introduction: One of the biggest challenges palaeontologists face is how to reconstruct whole animals from their fossils. Most fossil remains are just bones, so how do we go from the bones to the soft tissues? For extinct species, we make deductions by looking at their nearest living relatives. This process is called the extant phylogenetic bracket (EPB). A good example of using the EPB is in reconstructing dinosaurs. Dinosaurs are alive today as their descendants, birds, but the non-avian dinosaurs we all know and love from Jurassic Park look very different from modern birds. Dinosaurs also have other living relatives: the crocodilians. Along with the dinosaurs and some other extinct groups, these are part of a group called the archosaurs (which means ‘ruling reptile
Fossil Focus: Planktonic Foraminifera – Small Fossils, Big Impacts

Fossil Focus: Planktonic Foraminifera – Small Fossils, Big Impacts

Fossil Focus
by Janet Burke*1 Introduction and background: Although the microscopic creatures called planktonic foraminifera are still around today, most people have not heard of them. They don’t come to mind when the words "palaeontologist" or "fossil" are mentioned. They don’t have scales or claws, or big sharp teeth. They don’t even have mouths. If you were to visit the lab I work in, you wouldn’t see the specimens, just a row of compound microscopes and funny metal trays, slides and boxes of glass vials a little bigger than a pinky finger. If you look closer at those vials, each one contains hundreds upon hundreds of fossils, and each of those fossils has a story to tell. Etched into the nooks of its chambers and the very molecules of its calcite are facts about the ocean at a brief moment in tim
Fossil Focus: The ecology and evolution of the Lepospondyli

Fossil Focus: The ecology and evolution of the Lepospondyli

Fossil Focus
by Aodhán O'Gogain*1 Introduction and background During the Pennsylvanian subperiod (roughly 318 million to 299 million years ago), lush tropical rainforests covered much of what is now North America and Europe, but were then near Earth’s Equator. These tropical forests were teeming with animals, from 2-metre-long millipedes that scurried along among the roots to fish with fangs 10 centimetres in length that inhabited the associated rivers and estuaries. Living among these giants was a diverse group of small (less than 1 metre) vertebrates that resembled newts, lizards and snakes. These were the Lepospondyli, a sub-class of tetrapods that are characterized by having hourglass-shaped centrums, the central parts of their vertebrae. They had elongated, small bodies and short limbs, with one
Fossil Focus: The Archosaur Respiratory System — Or — Breathing Life into Dinosaurs

Fossil Focus: The Archosaur Respiratory System — Or — Breathing Life into Dinosaurs

Fossil Focus
by Robert Brocklehurst*1 Introduction and background Dinosaurs fascinate people more than almost any other group of fossil animals, and the general public is interested in many open questions on dinosaur biology. How fast could dinosaurs run? Were they warm blooded? If they had feathers, does that mean they could fly? These questions focus on dinosaur metabolism and movement, both of which are intimately linked with the respiratory system, because breathing — the ability to take in air, extract oxygen from it and then expel it from the body along with waste carbon dioxide— sets a fundamental upper limit on how much activity an organism is capable of. How did dinosaurs breathe? That’s probably not a question palaeontologists get asked as often as the others. Breathing is something we a