by Amelia Penny*1 Introduction and background The ability to build and maintain a skeleton is one of the major innovations in the history of life. During the Cambrian explosion, which began around 540 million years ago, diverse animal (metazoan) skeletons appeared suddenly in the fossil record. This is also when we first see evidence for predation, the ability to move around and most of the animal body plans we would recognize today. The ability to grow a resistant skeleton was a major factor in the evolutionary arms races of the Phanerozoic eon — the time since the Cambrian explosion — and it made possible the dizzying variety of shells, bones and teeth scattered throughout the Phanerozoic fossil record. But the origin of skeletons has a much deeper root, in the Proterozoic eon (2,500 m
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
by The Palaeontology [online] editorial board*1 Introduction Every now and then at Palaeontology [online], we like to take a look at the world of palaeontology and reflect on what is happening in the field. Contrary to stereotypes, we believe that palaeontology and associated disciplines represent a fast-moving and exciting area of science. To highlight this, the members of the editorial board have each chosen a favourite paper from 2017. Picking just one paper was difficult for all of us, and it means that we have highlighted just five articles out of the many hundreds published in the past 12 months. Nevertheless, we hope that our choices reflect the breadth and depth of palaeobiological research in the twenty-first century. The papers include incredibly small and ancient invertebrates...
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
A membranous sack that the fetus develops in.
These are a sensory system, usually found running as a line on the sides of fish, but also found in aquatic tetrapods. They sense differences in water pressure, allowing the animal to tell whether something is moving close to them.
The centrum forms the central body of the vertebrae and usually has a cylindrical shape with slightly concave surfaces on each side.
by Lukáš Laibl*1 Introduction: Trilobites are an iconic group of ancient animals, with a fossil record that dates back more than 500 million years and consists of some 17,000 species. These extinct arthropods are characterized by a hard, mineralized exoskeleton, which greatly enhances their chances of being preserved as fossils. The exoskeleton is thought to have been mineralised soon after they hatched from eggs, and so we can find various growth stages of trilobites in the fossil record, including individuals less than half a millimetre long. That makes it possible to study the entire post-embryonic development (that is, the development after they hatch from the egg) of numerous species. This is important because work on the development of ancient organisms provides data crucial for ou
Mineralised part of trilobite exoskeleton that is developed around the ventral margin of the body.