Fossils

HANDBOOKS FOSSILS DAVID J. WARD Photography by COLIN KEATES ABIPP DAVID J. WARD FGS

NEW EDITION DK LONDON DK DELHI Managing Editor Angeles Gavira Senior Editor Janashree Singha Managing Art Editor Michael Duffy Project Editor Hina Jain Production Editor George Nimmo Art Editor Shipra Jain Senior Production Controller Meskerem Berhane Illustrator Priyal Mote Managing Editor Soma B. Chowdhury Senior Managing Art Editor Arunesh Talapatra Senior Jacket Designer Suhita Dharamjit Senior DTP Designer Harish Aggarwal Jackets Editorial Coordinator Priyanka Sharma Managing Jackets Editor Saloni Singh Production Manager Pankaj Sharma Pre-production Manager Sunil Sharma DTP Designers Syed Md Farhan, Vikram Singh Editorial Head Glenda Fernandes Design Head Malavika Talukder Scientific Editor Alison E.M. Ward First published in Great Britain in 1992 This edition published in 2021 by Dorling Kindersley Limited DK, One Embassy Gardens, 8 Viaduct Gardens, London, SW11 7BW The authorised representative in the EEA is Dorling Kindersley Verlag GmbH. Arnulfstr. 124, 80636 Munich, Germany Copyright © 1992, 2000, 2021 Dorling Kindersley Limited A Penguin Random House Company Text copyright © 2021 David J. Ward 10 9 8 7 6 5 4 3 2 1 001–322113–Oct/2021 All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the copyright owner. A CIP catalogue record for this book is available from the British Library. ISBN 978-0-2414-7143-2 Printed and bound in China For the curious www.dk.com This book was made with Forest Stewardship Council ™ certified paper – one small step in DK’s commitment to a sustainable future. For more information go to www.dk.com/our-green-pledge

Contents VERTEBRATES 194 INTRODUCTION 6 Agnathans 194 Placoderms 196 Authors’ introduction 6 Chondrichthyans 198 How this book works 9 Acanthodians 210 What is a fossil? 10 Osteichthyans 211 Modes of preservation 12 Tetrapods 221 Geological time chart 14 Where to look 16 Lissamphibians 224 Collecting fossils 18 Amniotes 225 Preparing your collection 20 Reptiles 225 From hobby to science 22 Dinosaurs 245 Fossil identification key 24 Birds 256 Synapsids 260 INVERTEBRATES 32 Mammals 263 Foraminiferans 32 ALGAE 286 Sponges 33 Bryozoans 36 PLANTS 289 Worms 40 Trace fossils 42 Early land plants 289 Problematica 43 Hepatophytes 290 Graptolites 45 Sphenopsids 290 Corals 50 Ferns 292 Trilobites 56 Lycopods 294 Crustaceans 66 Pteridosperms 295 Chelicerates 73 Bennettites 300 Insects 76 Progymnosperms 300 Brachiopods 79 Cordaitales 301 Bivalves 94 Conifers 301 Scaphopods and Chitons 114 Ginkgos 307 Gastropods 115 Eudicot Nautiloids 134 Angiosperms 307 Ammonoids 141 Monocotyledonous Ammonites 144 Angiosperms 311 Belemnites and Squids 161 Glossary 312 Crinoids 166 Index 317 Echinoids 175 Acknowledgments 320 Asteroids 186 Ophiuroids 189 Blastoids 190 Cystoids 191 Carpoids 193

6 | Introduction AUTHOR’S INTRODUCTION Fossil collecting is a fascinating hobby specimens, and the academic challenge which has grown considerably in of identifying fossil finds. There are few popularity over the last few decades. other branches of science in which a Its appeal is understandable; it combines beginner can make a serious contribution the excitement of discovery with the to the knowledge of our planet’s practical skills of collecting and preparing remarkable prehistory. Originally the word “fossil” (derived from the Trachyphyllia Latin word fossilis, meaning “to be dug up”) referred (coral) to anything that had been buried. It included not only the petrified remains of plants and animals, apparent in the but also rocks, minerals, and man-made artefacts, 17th and 18th such as coins. It is now used only to refer to centuries. This the naturally buried and preserved remains of was aided by the organisms that lived long before historic times. publication of books figuring collections of YEARS OF SPECULATION fossils, and by a wider Fossils have intrigued people for generations. understanding of natural Greek philosophers regarded them as rather strange, history. One key observation, natural phenomena, which formed in the earth, in a in the early 19th century, was that similar way to a stalactite or crystal. Martin Luther the sequence of sedimentary rocks in a region was (1483–1546) believed that fossil finds on mountain essentially the same over a large distance and that tops were evidence of the biblical Flood. In his each layer could be recognised by its own suite of notebooks, Leonardo da Vinci (1452-1519) suggested fossils. This allowed rocks to be identified and traced that fossils were the petrified remains of once-living over large distances and was of considerable help organisms. His views, heretical for his era, were in the production of the first geological maps. This withheld until his notebooks were published in the led to the modern sciences of palaeontology (the 19th century. The true nature of fossils became slowly scientific study of fossils) and stratigraphy (the study of rock strata). Today, palaeontology is concerned only with the remains of animals and plants that lived more than 10,000 years ago. CLASSIFICATION Fossils are usually referred to by their two-part scientific name, although a few have popular or informal names as well. Diplomystus (fish)

Introduction | 7 Hemicidaris to a different genus. When correctly used, a scientific (sea urchin) name refers only to a single type of organism and can be understood by scientists all over the world. For instance, the oyster Gryphaea is often called The basic unit of classification is the species. There a “Devil’s Toenail” and brachiopods are known as are many and varied definitions, but essentially all “lamp shells”. These names have their uses but lack members of a species look similar and are able the precision needed in science; more importantly, to interbreed. they are not internationally accepted and can be confusing. The usual form is to give the full scientific The definition of a species is based on the name, usually written in italics, followed by the name combination of a detailed written description, of the author, the person who first described the illustrations and where practical, a specimen or group species. The first part is the genus, the second part of specimens preserved for posterity in a museum is the species. If the author’s name is in brackets, it or similar institution. The key specimen used to means that the species has, at later date, been moved identify others of the same species is referred to as the Holotype. One or more species may be grouped into a genus, linked by features they share. This, along with the family (a group of genera) and the order (a group of families) makes up the pedigree or family tree of an organism. All the stages above “species” are artificial, a man-made classification, and they tend to change depending on current opinion. This can be frustrating for both the beginner and the specialist. Field trip: January 1988 The author, David Ward (right) with museum curator, Cyril Walker ( (left), in the southern Sahara, examining an exciting fossil find: a scatter of dinosaur bones. Some of the bones found can be seen on p.249.

8 | Introduction AIMS AND LIMITATIONS Crinoid This book is intended to assist the collector by stem illustrating a broad range of fossils, from those most likely to be found, to some of the more Amber (fossilized spectacular, but less common. The fossils were plant resin) chosen from the Natural History Museum, London, UK, one of the largest and most It would be impossible to show a diverse collections in the world, as well as photograph of every type of fossil. favourites from the author’s personal However, the range and diversity collection. Microscopic specimens have not of specimens contained in this book been included; although many are fascinating should enable the collector to find a and visually stunning, their study is quite specialized. photograph and description of Most major groups of fossils are included, from worms something sufficiently close to attempt a to dinosaurs, from ammonites to humans, and from all geological ages and continents. The selection and preliminary identification. In this revised description of each fossil has been assisted by and updated edition, we have attempted experts who work on the many different types to include some of the fossils that are now of fossil included. Technical terms have widely available in rock and mineral shops and that been kept to a minimum, but where this are both legally and sustainably sourced. has proved difficult, they have been explained in a comprehensive glossary (see pp.312–316). Many fossils, particularly the larger reptiles and mammals, are only occasionally found whole. This poses a problem in terms of identification. In such cases, small parts of the skeleton have been illustrated. Homo habilis (skull Calliostoma of early human) (gastropod)

Introduction | 9 HOW THIS BOOK WORKS THE MAIN BODY OF THE BOOK is annotation. Occasionally, an unusual divided into four parts: invertebrates, specimen, but one that makes an vertebrates, algae, and plants. Within interesting point, has been chosen. each division, the main groups are Each photograph is accompanied by introduced. The genus is the starting a reconstruction of a typical species point of identification. Usually a typical of the organism in life. Some of the or relatively common species of the reconstruction details, such as the colour, described genus is illustrated. Identifying are educated guesswork. This annotated features are clearly highlighted in example shows a typical page. name of the group to name of the subgroup to informal name of which the fossil belongs which the fossil belongs the fossil Vertebrates | 241 Group: CROCODYLIFORMES Subgroup: METRIORHYNCHIDAE Informal name: Marine crocodile genus name Gracilineustes nostril main text The metriorhynchid family is the most specialized of all known long snout caption giving the describing the crocodiles, and is perhaps the only archosaur group to become fully species name, main identifying aquatic. Changes in its original habit are clearly reflected in its Gracilineustes author, lithological characteristics skeleton, for the forelimbs were transformed into paddles, the leedsi (Andrews); unit (when known), neck was shortened, the tail bent downwards at the end to Oxford Clay; Late geological age, and of the genus support a large caudal fin, and the body armour lost. In Jurassic; UK. country of origin contrast to their more terrestrial crocodilian cousins, of the specimen. information the skull is long and lightly built – this was another articulation neural If the species has about the requirement for a fully aquatic mode of life. spine been moved to a different genus habitat and HABITAT Species of Metriorhynchus were particularly after it had been mode of life of common in the Jurassic seas of Europe, where they hunted named, then the for fish and squid-like animals which shared the same author’s name the genus habitat. It may be that they only came to land to lay appears in brackets. their eggs, in the manner of modern turtles. It is also Abbreviations used general possible that they hauled themselves on to sand in this caption are information banks to bask after hunting for fish. sp.=species; pertaining either REMARK The metriorhynchids belong to the cf.=compares to the genus or primitive mesosuchian suborder of crocodiles, favourably with to the particular which appeared in the Triassic but finally became extinct in the earliest part of the specimen Tertiary, some 60 million years ago. featured annotation eye sockets highlighting the main identifying flat-faced Vertebra label giving articulation information on features of the fossil or part the genus plain bone surface of fossil featured large temporal illustration opening showing a typical species of the fossil abbreviations jaw Skull genus in life. Under used in this articulation the illustration is band are a measurement E. = Early; Typical length which gives an 3m (10ft) indication of the M. = Middle; organism’s size L. = Late Occurrence: Range: Middle–Late Jurassic Distribution: Europe, S. America geological range of geographical distribution the number of symbols indicates the genus of the genus the frequency with which the fossil occurs (one=rare; five=common)

10 | Introduction WHAT IS A FOSSIL? FOSSILS ARE THE REMAINS of long- life (known as a trace fossil). For dead plants and animals that have partly fossilization to occur, rapid burial, escaped the rotting process and have, usually by water-borne sediment, after many years, become part of is required. This is often followed by the Earth’s crust. A fossil may be the chemical alteration, where minerals preserved remains of the organism may be added or removed. The itself, the impression of it in the replacement by and/or addition of sediment, or marks made by it in minerals usually aids preservation. Fossil dung Trace fossils are true fossils. This dropping (below left) is probably from an extinct shark. It is usually difficult to relate coprolites to the animal that produced them. Reptile footprint Horse tooth While difficult to identify to a particular This cheek tooth (below) species, fossil footprints (above) can looks like that of a modern provide valuable information about horse, but is actually a the organism’s behaviour, such as fossil. Over the centuries, speed, weight, and mode of life. its organic tissue has been replaced by strengthening Mummified frog mineral salts, ensuring Mummification – its preservation. the natural drying of an organism – has meant that the frog (right) has progressed part of the way towards becoming a fossil. To ensure proper preservation, it must become entombed in a medium that would guard against further decomposition. Banded flint Flints (right) are sometimes mistaken for fossils. During formation, flint can be deposited in bands. With a little weathering and staining, these flints can resemble fossil corals, molluscs, worms, and trilobites.

Introduction | 11 Birds’ nest Foot-shaped The birds’ nest (above) is not a Cretaceous flints come in many forms; this one resembles a fossil; it is a modern nest that human foot (below). Some flints are has been petrified in a spring. crustacean burrow infills; if so they are regarded as trace fossils. Clay bottle Objects as mundane as a collapsed clay bottle (above) are sometimes mistaken for fossils. HOW FOSSILIZATION OCCURS become fossilized. This often occurs when the Fossilization is, at best, a risky process which relies organism decaying in the sediment alters the on a chain of favourable circumstances. The vast local conditions and promotes the incorporation majority of the plants and animals that have ever of mineral salts within its structure, a process lived have completely disappeared without trace, known as mineralization. This chemical change leaving no fossil record. With rare exceptions, it is often enables the fossil to become more resistant only the skeletal or hard parts of an organism that than the surrounding sediment. c a Fossilization d After death an organism may slowly Water column disintegrate (a) or become buried in g soft sediment (b). However, it may be e b disturbed or digested by sediment- feeding organisms, or current or wave f Soft sediment activity may re-expose it (c). As the Consolidated sediment sediment compacts and the complex chemical reactions of diagenesis occur, i the potential fossil may be dissolved (d). But if the sediment is sufficiently h consolidated, a mould may be formed (e). Percolating mineral solutions may infill the mould, creating a cast (f). Some enter the sediment relatively unaltered by mineralization (g). If buried and subjected over time to increased temperature and pressure, sedimentary rocks become softened and distorted (metamorphosed), and ultimately destroyed (h). As rocks are folded, uplifted, and eroded, buried fossils may be exposed on the surface (i). Metamorphic rock

12 | Introduction MODES OF PRESERVATION TO BECOME preserved as a fossil, some these cases, the living organism has been of the normal processes of decay must caught in the sticky substance (tar or resin) be permanently arrested. This usually which has then been fossilized, ensuring involves isolating the organisms that preservation. If limestone, phosphate, cause decay from the air or water, and or pyrite is deposited in the sediment then filling any voids in the hard tissue surrounding a decaying plant, it forms a with additional minerals. The vast “tomb” that may preserve very fine details of majority of fossils are, therefore, found in the organism. Silicified or petrified wood can freshwater or marine sediments, where produce spectacular colour effects, although oxygen-deprived silt or clay has buried the cell preservation itself is often poor. the organism soon after death. If the sediment conditions remain favourable Trapped in amber (see pp.10–11), the organism may be Amber, the fossilized resin of a plant or tree, sometimes preserved as a fossil. In the case of preserves not only the external, but also the internal, mummification, the arrest of decay structure of an organism. Insects, spiders (above), is only temporary; a mummified frogs, and lizards may be preserved in this way. organism will begin to decay as soon as it is exposed to air once again. Under exceptional circumstances, soft-tissue details may be preserved. Insects in amber and mammoths in ice or tar are well-known examples. In both Silicification This is a form of “petrification”. Silicified wood (left) can often be found in both terrestrial and freshwater deposits, usually sands and silts. Weathering volcanic ash usually supplies silica, which is gradually incorporated into partially decayed wood. Generally, the cell structure of silicified wood is quite poorly preserved; however, the presence of iron and other minerals can produce some really spectacular colouring.

Introduction | 13 Phosphatization Mummification Bones and teeth (above), which The dry, sterile atmosphere of a cave normally dissolve on the sea bed has preserved this moa foot (above) or leach from the sediment, are more likely to be preserved if with some soft tissue intact; usually large quantities of phosphates are bones are only preserved in a present. Phosphatic deposits are a fragile state. Mummification is source of well-preserved fossils only a pause in disintegration and are often mined commercially. and is not true fossilization. Freezing Siberian mammoths are often found preserved in permafrost. Once thawed, they will decay unless action is taken, but the hair is relatively durable. Tar and sand A mixture of tar and sand has embalmed this beetle (left). This could be stable for thousands, but not millions, of years. Limestone tomb The completeness of this fragile crinoid, entombed in limestone (left), suggests that the calcareous nodule encasing it formed soon after death. Pyritization The shell and chambers of this ammonite (right) were replaced by iron pyrite. This is often unstable in moist air, so it needs to be stored in very dry conditions.

14 | Introduction GEOLOGICAL TIME CHART THE PLANET EARTH was formed 4,600 for example, Jurassic is named after the million years ago, with life present for Jura Mountains between France and at least 3,850 million years. Although Switzerland; Devonian after the rocks multicellular life appeared over 1,000 in Devon, UK. These periods provide a million years ago, remains from that framework which, while estimates of their period are scarce. The first organisms actual age may alter quite dramatically, with hard parts, allowing fossils to allow rocks and fossil remains to be become relatively common, appeared correlated worldwide. about 550 million years ago. Geological time is divided into periods, usually Fish Synapsids named after the area where the rocks Lissamphibians Dinosaurs from that period were first exposed: Birds Reptiles Mammals Humans Vertebrates Echinoderms Brachiopods Chelicerates InseCcrtus stacea BiGvaalsvtreospodsModern Cephalopods Worms Chart key on the chart indicate the different groupIsnovfertebrates The symbols plants and animals, both vertebrates and invertebrates, some living, some long extinct. The blue radial lines show their presumed relationships. The colour bands represent the conventional geological periods, stretching from the Ediacaran period (635 million years ago), to the present (Recent) time.

Introduction | 15 Pre- Million Cambrian years ago Ediacaran550 Tetrapods Graptolites Cambrian 500 Amniotes Ordovician Trilobites Ammonites and Belemnites Silurian 400 Devonian Carboniferous 300 Corals and Jellyfish Ferns Permian 200 Triassic SpongesBryozoa Ginkgos Jurassic Seed Ferns Algae Cycads Conifers Cretaceous plants SpheEnaorlpiysvdasscular 100 Foraminifera Angiosperms Paleocene Eocene Oligocene Miocene Pliocene Pleistocene Holocene or Recent Plants

16 | Introduction WHERE TO LOOK YOU CAN FIND FOSSILS in most places A visit to a local museum is often useful where sedimentary rocks, such as clays, but up-to-date information from other shales, and limestones, are exposed. collectors is better. Consider joining a Exposures of hard rock recover very natural history society or a rock and slowly from collecting and can be mineral club. They can often gain access disappointing. Artificial exposures, like to private localities. Most geological road cuts or quarries, can be much more societies have a code of conduct relating productive. Exposures of softer rocks can to collecting, which it is advisable to be good sites, provided they have not follow. Wherever you decide to collect been too badly altered by metamorphosis. fossils, be aware of local regulations and Inland sections in sands and clays tend obtain permission from the owner. to degrade rapidly, become overgrown, and lost. Here temporary exposures are valuable, along with continually eroding river or coastal sections. Establishing the age of the rocks, with the aid of a geological map, will give you an idea of what sort of fossils to expect. Most libraries have geological guides, but remember that they may be out of date: many an hour has been spent looking for quarries that have been infilled and had houses built on them. Coastal sites Wave-washed cliffs and foreshore exposures (above) are good places to search for fossils. Be aware of the state of the tide when you are rounding headlands. Wear a hard hat to protect you from small stones dislodged by startled seabirds, but remember it will not protect you from larger falling rocks. Quarries Supervised parties are usually allowed to collect fossils in quarries (left), but individuals may be discouraged. Check beforehand whether there are places, usually around active faces, that are out-of-bounds. Hard hats are a normal requirement. The staff often know where the best specimens may be found.

Introduction | 17 Trilobite Concoryphe (left), an eyeless deep-water genus, was found in a hard Cambrian mudstone. Arid terrains Although erosion is slow in deserts (below) and badlands, the large areas of exposure that exist can more than compensate. National parks Hammering rocks is often discouraged in areas of natural beauty and is illegal in most national parks (above), so please be sensitive. In this way, fossils will still be there for future generations. Rugged terrain Fossils are often concentrated along particular bedding planes; the combination of a potentially interesting area and well-stratified rocks make an ideal hunting ground (below).

18 | Introduction COLLECTING FOSSILS COLLECTING FOSSILS is a very relaxing it as much as possible. Cover it with and intellectually stimulating hobby, but layers of a separator (wet paper or it is one that can often be frustrated by cling film), followed by layers of plaster not having suitable field equipment. bandage. Once the plaster has been set, It is clearly impossible to cater for all you can lift the fossil out of the rock eventualities, but the tools shown below face, and then repeat the process on form a basic selection that covers most the underside. situations. However, it is always better to leave a fossil in the field than to try to dig Your safety should be a primary it out in a hurry with the wrong tools; this concern. Hard hats, goggles, and gloves could damage a valuable scientific find. are essential. Finally, before you set out on an expedition, ask other collectors, who Occasionally, equipment for plastering are familiar with the area you intend to is required. You use this to protect fragile visit, exactly what tools you will need. fossils before you remove them from the rock. Clean the fossil and expose SAFETY EQUIPMENT compass Rocks can be sharp and dangerous. A hard hat is essential if collecting near high rock faces. Goggles will shield your eyes from dust and stones, and gloves will protect your hands. map GPS long tape measure Map, GPS, and compass A geological map and a compass will help you to find fossil localities. Take a long tape measure to record the level of the bed in which you find fossils. Notebook and smartphone Record field notes, such as locality, type of rock, and fossils seen, in a sturdy notebook in waterproof ink. A photograph can also prove invaluable.

Introduction | 19 mallet Field tools For extracting fossils from hard rocks, geological a sturdy mallet and several guarded hammer chisels are essential equipment. A pick-ended geological hammer is useful on most types of rock. Soft sediments are best tackled with a trowel or a spade. trowel hand lens guarded Sieve chisels Use a sieve to separate fossils from sands and gravels. Usually one or two different meshes are needed to avoid losing small fossils. Plastering Protect fragile fossils in a plaster jacket before removing them from the rock. This prevents them from shattering. plaster small large bandages brush brush plastic sieve Spade When you are searching for fossils in soft sediments, such as sands, silts, and clays, a narrow-bladed spade, rather than a conventional geological hammer, is the most useful tool for clearing an area around the fossil.

20 | Introduction PREPARING YOUR COLLECTION UNLIKE MOST OUTDOOR activities, repositioned later. Plastic boxes are ideal fossil collecting does not end when for storing small fossils. Open cardboard you return from a field trip. A freshly trays suit larger specimens. Use glass collected specimen usually needs vials, microscope slides, or even gelatin cleaning to remove any adherent matrix. capsules to house very small specimens. This can be a very simple procedure, such as dusting sand off a specimen, or, it may For best practice, each fossil should involve using dilute acids to remove have a catalogue number but also be fossils encased in hard rock. For example, housed with its own label as a backup. you will need acid to remove fossilized The information can be stored in a card teeth from an unconsolidated matrix of index file or a computer catalogue. The shell debris. This is a tricky process that label and catalogue should include the should be first attempted with the following data: the name, the lithological guidance of an expert. unit, and the rock’s geological age. This should be followed by the locality, its map Fragile fossils can be strengthened with reference, the country or state, and the a dilute solution of consolidant. Use a glue date it was collected. A fossil without that can be removed, so that a joint can be these details is of little scientific value. brushes forceps Cleaning fossils dental probes Use a variety of large and small brushes and dental probes to clean the specimen, and to remove small fragments of rock. Chip off more resistant matrix with a lightweight hammer and chisel or with an engraving tool. Handle small or fragile specimens very carefully, preferably with fine forceps. It is a good idea to protect them with a consolidant, so that they will not break up when they are handled or transported. sieve dilute acid engraving tool airpen sharks’ teeth Sieving Organic acids Use a stack of stainless steel or brass Use dilute organic acids, sieves to separate samples containing e.g. vinegar, to remove small fossils, such as sharks’ teeth, into the surplus matrix from different sizes. Brass sieves are soft and a calcareous specimen. damaged by sea water, and so are not Practice the procedure on an suitable for use in the field. unimportant fossil first, to avoid damaging a valuable specimen.

Introduction | 21 Indexing organized Store your fossils in individual plastic fossil boxes or shallow cardboard trays. Label collection each specimen carefully. Keep a set of plastic duplicate records in a card-file system boxes or on a computer or memory sticks; include details of the preservatives, glues, and hardeners used. card-file index memory sticks Microscope A binocular microscope is useful for sorting small fossils from a sieved residue, or examining details of large specimens.

22 | Introduction FROM HOBBY TO SCIENCE BEGINNERS NORMALLY START by that their true value lies in the scientific collecting any fossil that comes their way. information they represent. Donating This is not a bad idea, as there is a lot to specimens to a local or national museum learn about the hobby. After a while, collection is one way a fossil collector can however, most collectors specialize in repay any help that he or she has received a particular group of fossils, such as from museum staff in the past; most trilobites, ammonites, or plant fossils, museums rely very heavily on the or perhaps an age or locality. generosity of amateur collectors. Initially, most collectors tend to regard It is no exaggeration to say that fossils merely as objects that are attractive palaeontology is one of the few sciences in their own right, a pleasure to admire where an amateur is able make a and own. With time and experience, significant contribution to the state of the specimens themselves become less knowledge – indeed, this is probably important and collectors soon realize one of its major attractions as a hobby. National museums These often have an identification service, and good regional and national exhibits of fossils (left), allowing collectors to make their own determinations. Only the best of a vast collection is on display, so try not to be discouraged if your fossils don’t quite match in quality. The museum shop will usually have a good selection of books on fossil identification. Local museums Most museum curators are happy to give advice, discuss the local geology, and help identify problem specimens (right). Their knowledge and enthusiasm has inspired many young collectors to pursue geology as a career. Local museums can also put you in touch with the nearest geological society. Easy find Shark’s teeth are a favourite among fossil collectors. In rocks of the right age, they are quite easy to find.

Introduction | 23 Eryops megalocephalus Cope Most fossil collectors dream of finding Museum exhibit something new. This need not be a This giant amphibian (above) is from the Permian large and spectacular specimen, like of Texas, USA. Magnificent specimens like this, a dinosaur; it is more often a small and reconstructed by palaeontologists, are a feature apparently insignificant fossil. The skill, of natural history museums worldwide. for the amateur palaeontologist, lies in recognizing something unusual. If it BUYING FOSSILS is a new species, a description can You can purchase small fossils, such as be published in a scientific journal, molluscs and trilobites, quite cheaply in accompanied by a photograph and details rock and mineral shops, at fossil shows, of the locality; a procedure that can take and on the internet. Collecting, owning, several years. The specimen should ideally and exporting fossils is illegal in many be housed in a museum collection, which countries, although possessing them ensures that all those interested can study outside of that country may not be an it. A private collection is not usually offence. It is important to respect such acceptable if it is not open to laws by ensuring that all potential the public. Parting with a purchases have been legally exported. prize specimen can be difficult, but it is Reference books necessary if the full Libraries may house old illustrated monographs. potential of the Palaeontology is one of the few branches of discovery is to science in which something written over a be realized. century ago can still be relevant.

24 | Identification key FOSSIL IDENTIFICATION KEY THE FOSSIL RECORD is so vast that to of the book where the group is covered in give adequate coverage in a book this detail. When attempting an identification, size is impossible. Nevertheless, typical it is vital to relate the range of any fossil examples of most of the more common to the rock in which your particular groups of fossils have been illustrated specimen is found; for instance, you do here. In this way, even if a particular not find trilobites in the Cretaceous, nor genus is not illustrated, a similar mammals in the Devonian. A look at the organism will be shown. Over the next geological time chart on pages 14–15 will eight pages, visual examples of each help you with this. The key is divided into major group of fossils are given, along three sections: invertebrates, vertebrates, with a concise description and the pages and plants. INVERTEBRATES WORMS FORAMINIFERANS Burrows, tracks, or calcareous tubes; usually spiral, cemented to objects. Can be confused Small (some microscopic), multichambered, with teredinid tubes (p.111), scaphopods (p.114), calcareous objects; either round, discoidal, or or corals (p.50). ovoid. Usually present in large numbers, they Range Cambrian–Recent can be rock-forming. Range Cambrian–Recent Test of Tubes of Tubes of Nummulites Rotularia Proliserpula Page: 32 Pages: 40–41 SPONGES AND BRYOZOANS Skeleton of Rhizopoterion Pages: 33–39 Composed of calcite, silica, or as an outline on a bedding plane. Shaped more like a plant than an Skeleton of animal; irregular, often branching, tree-like; size Raphidonema variable. Sponges are generally thick-walled, with a featureless or coarsely ornamented surface. Bryozoa are usually thin-walled with a delicate pore network; they can encrust other fossils or pebbles. They can be confused with corals (p.50) or calcareous algae (pp.286–288). Range (sponges) Cambrian–Recent Range (bryozoa) Ordovician–Recent Skeleton of Constellaria

Identification key | 25 TRACE FOSSILS AND PROBLEMATICA Footprint of Tetrapod These encompass tracks, trails, borings, and burrows. Generally they are radiating, feeding, or tubular Pages: 42–44 burrow structures made by worms, arthropods, echinoids, molluscs, or they are walking tracks of Trace of arthropods. Terrestrial, shallow lake sediments may Chondrites show regularly spaced depressions made by “footprints”. The systematic Imprint of position of problematicans is Spriggina uncertain because they are either poorly preserved or they resemble no modern fossil group. Range Precambrian–Recent GRAPTOLITES Skeleton of Retiolites These are impressions on rocks resembling watch springs, fretsaw blades, or meshwork. “Teeth” may be on one or both sides of stipe, which may be single or multiple. Graptolites may be confused with some plant remains (pp.286–311), or bryozoa (pp.36–39), or an oblique section of crinoid stem (p.168). Range Ordovician–Carboniferous Skeleton of Pages: 45–49 Didymograptus Skeleton of Phyllograptus CORALS Colony of Colpophyllia Shapes are very variable: horn-like, tube-like, or tree-like. The skeleton is calcareous. There are one Pages: 50–55 or many calices; each individual calice is divided by a series of radial plates giving a star-like appearance. Calices may be closely abutted or laterally fused in meandering chains (like brain coral, p.54). The size of the colony can vary from less than a centimetre to several metres. They can be confused with encrusting bryozoa (p.36), calcareous algae (p.287), serpulid worm tubes (p.40), or sponges (p.33). Range Ordovician–Recent Colony of Calice of Favosites Trachyphyllia

26 | Identification key ARTHROPODS locomotory, sensory, or feeding elements. Moulting is a common feature of arthropods – otherwise Arthropods have segmented bodies with a their growth would be constrained by the external differentiated anterior end. The body is covered by cuticle. Arthropods include the Trilobites, the a cuticle, or shell, that acts as an external skeleton Crustacea (crabs, lobsters, barnacles, and shrimps), (exoskeleton). The exoskeleton is sometimes the Chelicerates (king crabs, scorpions, and spiders), strengthened by calcium carbonate or calcium and the Uniramia (millipedes and the Insects). phosphate. Arthropods have a variable number of appendages (legs), which are specialized into TRILOBITES CHELICERATES These possess a flattened, The body is divided into a mineralized, calcium fused head, thorax, and carbonate shell, and are abdomen. They can be preserved in three dimensions, confused with some or as an impression. The trilobites and insects. eyes are often fragmented. Rarely found as fossils. The thorax may segment. Range Cambrian–Recent Range Cambrian–Permian Imprint of Exoskeleton Internal Mesolimulus of Phacops mould of Body of Dolomedes Pages: 73–75 Olenellus INSECTS Pages: 56–65 These are divided into head, CRUSTACEANS thorax, and abdomen. The adults have six legs and Usually the ornamented sometimes wings. phosphatic carapace is Range Devonian–Recent preserved; sometimes limb fragments, calcareous plates, Exoskeleton or bivalved shells, are found. of Hydrophilus Range Cambrian–Recent Pages: 76–78 Imprint of Petalura Imprint of Hymenocaris Pages: 66–72 Exoskeleton of Archaeogeryon BRACHIOPODS The shells have two symmetrical, Pages: 79–93 Shell of Goniorhynchia Shell of Terebratula calcareous, or chitinous, dissimilar valves. One valve usually bears a hole (pedicle foramen), through which it is attached to the substrate. They are common in older rocks, often in large “nests” of a single species. Range Cambrian–Recent Shell of Lingula

Identification key | 27 MOLLUSCS families of bivalve and gastropod have entered fresh water. Some gastropods have become air Molluscs are a very diverse group that includes the breathing and colonized the land. They can be chitons, scaphopods, bivalves, gastropods, and filter feeders (most bivalves), herbivores (some cephalopods. Nearly all molluscs have calcium- gastropods), carnivores (gastropods, cephalopods). carbonate shells; only a few genera of gastropods, One major group, the ammonoids, became extinct cephalopods, and nudibranchs lack this. The soft at the end of the Cretaceous. body is rarely preserved, so molluscs are classified by their shell structure. Most are marine; only a few BIVALVES Pages: 94–113 Two valves, similar in shape but each Cast of Shell of inequilateral; exceptions are oysters and Whiteavesia Crassatella rudists. May be loose in the sediment or cemented to a firm substrate. May be confused with brachiopods (pp.79–93) and corals (p.50). Range Cambrian–Recent CHITONS AND SCAPHOPODS GASTROPODS Chitons: ridged, tile-like plates. Single, asymmetrical, Pages: 115–133 Scaphopods: curved; tapering. spiral, unchambered Range (Chitons) Cambrian– Valves of calcium-carbonate shell. Recent Range (Scaphopods) Helminthochiton Range Cambrian– Ordovician–Recent Recent Page: 114 Shell of Shell of Dentalium Turritella Shell of Ecphora NAUTILOIDS Pages: 134–140 Straight, curving, or loosely or lightly Cast of Section of coiled calcium-carbonate shells, divided Orthoceras unknown nautilus into a chambered phragmocone and a living chamber. The chambers are connected by a tube (siphuncle). Range Cambrian–Recent AMMONOIDS AND AMMONITES BELEMNITES AND SQUIDS Similar to nautiloids but Cast of These have a solid, tapering, Guard of with a ventral siphuncle. Mantelliceras crystalline calcium-carbonate Belemnitella Chambers give rise to a guard, partially enclosing complex suture. Ribs and a chambered tubercles are common. phragmocone. Range Devonian–Cretaceous Range Jurassic– Recent Pages: 141–160 Pages: 161–165

28 | Identification key ECHINODERMS The echinoderms include the echinoids (sea All are restricted to fully marine environments and urchins), holothuroids (sea cucumbers), asteroids thus act as marine indicators. Most possess solid (starfish), crinoids (sea lilies), as well as the extinct calcite skeletons that fall apart on death; crinoidal blastoids, cystoids, and carpoids. All have five-rayed debris can be so abundant as to be rock forming symmetry except for some echinoids and carpoids. (see p.168). Some irregular echinoids (see Micraster They possess a complex water vascular system that p.185) have evolved in a manner that makes it operates a network of multi-functional tube feet. possible for them to be used as zone fossils. CRINOIDS Pages: 166–174 Comprise a columnar stem, head (or calyx), and Calyx of arms (pinnules); some species are stemless. On Marsupites death, they usually disintegrate to isolated calyx ossicles and round, pentagonal, or star-shaped, Calyx of crystalline calcite stem segments. Cyathocrinites Range Cambrian–Recent ECHINOIDS ASTEROIDS The shell or test is composed of thin, loosely These are five-sided, with margins edged with solid cemented, calcite plates. The test may be calcitic blocks (ossicles). Occasionally preserved as sub-spherical and have five-rayed symmetry, or whole, articulated specimens; more usually found heart-shaped, or dorso-ventrally flattened with as isolated ossicles. a bilateral symmetry (characterized by irregular Range Ordovician–Recent echinoids). Plates bear spines that may be short and bristle-like or large and club-shaped. Pages: Cast of Range Ordovician–Recent 186–188 Tropidaster Test of OPHIUROIDS Page: 189 Hemicidaris These small, individual ossicles Skeleton of Pages: 175–185 are common in sieved residues; Palaeocoma articulated specimens are rare. Test of The central disk of calcite Hemiaster plates has five, snake-like arms. They are common in deep-water sediments. Range Ordovician–Recent BLASTOIDS CYSTOIDS CARPOIDS Usually intact, compact calyx. Short stem, calyx of many Stem short, asymmetrical Range Ordovician–Permian small, irregular plates. calyx of small polygonal Range Cambrian– plates, no arms. Page: 190 Permian Range Cambrian– Devonian Calyx of Pages: 191–192 Pentremites Page: 193 Calyx and stem of Calyx of Cothurnocystis Lepadocrinites

Identification key | 29 VERTEBRATES A vertebrate is an animal possessing a flexible amphibians, reptiles, mammals, and birds. The segmented spinal column composed of cartilage oldest known fossil vertebrate is from the early or bone. The principle vertebrate groups are fish, Cambrian period. FISH Fish are a very diverse group of marine and and pharyngeal perforations (usually known freshwater vertebrates. All fish possess as gills). They all have paired pelvic and segmented body musculature, a brain, spinal pectoral fins, unpaired dorsal and anal fins, cord, notochord, terminal mouth, hollow gut, and a post-anal tail. AGNATHANS Jawless fish covered with fine scales. The head may Head shield of Pteraspis be encased in an armoured shell of fused scales. Range Late Cambrian–Late Devonian Pages: 194–195 GNATHOSTOMES Gnathostomes are vertebrates that possess a cranium with a hinged lower jaw. PLACODERMS ACANTHODIANS Heavily armoured fish Skeleton of Found as isolated Skeleton of with large pectoral Bothriolepis scales, teeth, and Diplacanthus fins and sometimes ornamented fin dorsal fin spines. spines. Fin spines Some have paired can be confused bony plates in with those of a shark. their jaws. Teeth lack enamel. Range Early Devonian– Range Late Silurian– Early Carboniferous Early Permian Pages: 196–197 Page: 210 CHONDRICHTHYANS OSTEICHTHYANS Skeletons of sharks, rays, and chimaeroids Also known as bony fish. Scales of are rarely preserved articulated. Usually These are found as teeth, Lepidotus teeth, tooth plates, placoid scales, fin spines, bones, scales, fin spines, and calcified vertebrae are found. Sharks’ and otoliths. teeth have enameloid crowns. Range Late Silurian–Recent Range Late Silurian–Recent Pages: 211–220 Tooth of Tooth of Otolith of TETRAPODS Striatolamia Ptychodus Centroberyx See next page Pages: 198–209

30 | Identification key TETRAPODS Tetrapods are a group of LISSAMPHIBIANS four-limbed vertebrates that were derived from The bones are solid or hollow; the skull is composed of lobe-finned fish. It includes extant and fused bony plates. The teeth are simple with no roots. extinct amphibians, reptiles, dinosaurs, and Vertebrae may be unitary or multipartite and have neural birds, and the synapsids (including mammals). canals. Limb bones may bear a variable number of digits. Pages: 221–224 Range Late Devonian–Recent. Page: 224 Skeleton of Rana AMNIOTES Amniotes are tetrapod vertebrates that include synapsids, mammals, reptiles, dinosaurs, and birds. They lack the larval stage of lissamphibians and have an amniotic membrane protecting the embryo. REPTILES Diverse grouping of DINOSAURS BIRDS tetrapod. Skulls with or without secondary Bones are solid, or thick-walled Skull is light, teeth are openings. Limb bones are and hollow. Skull is lightly built usually absent. Limb usually hollow (except with fixed quadrate bones; bones are hollow and turtles). Teeth are enamelled enamelled teeth lie in deep thin-walled, with a single long root, set in sockets. Hip socket sternum is sockets or fixed to jaws. is perforated; keeled, ankle Range Late Carboniferous– head of thigh bones are fused. Recent bone is angled Range Late inwards. Jurassic–Recent Carapace of Trionyx Range Late Triassic– Limb bone of Pages: 225–244 Cretaceous Aepyornis Tooth of Jobaria Pages: 256–259 Pages: 245–255 SYNAPSIDS MAMMALS Bones are solid, vertebrae Limb bones are usually hollow and Tooth of biconcave, neural canal is present. thin-walled; epiphyseal plates present. Tetralophodon Skull is often massive. Teeth differ. Teeth are enamel-covered, and Range Late Carboniferous– Jurassic multi-faceted, some have bony roots. Range Late Triassic–Recent Skull of Cynognathus Pages: 260–262 Skull roof of Bison Pages: 263–285

ALGAE PLANTS Identification key | 31 Preserved as microscopic EARLY LAND PLANTS SPHENOPSIDS single-celled plants, banded AND HEPATOPHYTES stromatolitic masses, calcified Vertical stems emerge from structures, or thin impressions. Present as small, upright, underground rhizomes. The Range Precambrian–Recent branching, leafless, aerial main stem is jointed, and shoots, or low thallus with pith-filled with leafed stems. Pages: 286–288 ovoid spores; no true roots. Range Early Devonian–Recent Range Late Silurian–Recent Pages: 290–291 Colony of Pages: Frond of Mastopora 289–290 Asterophyllites Thallus of Hexagonocaulon FERNS, LYCOPODS, AND PTERIDOSPERMS BENNETTITES AND PROGYMNOSPERMS The fronds of ferns and pteridosperms are Foliage grows from large trunk. divided into multiple leaflets. In lycopods, the Cones are in centre of leaves are spirally arranged. Spores are borne on crown or leaf bases; the underside of leaves in ferns; in cones in the flowers are present. leaf axil in lycopods. Pteridosperm fronds bear a Range Triassic– Recent single seed. Range Late Silurian–Recent Page: 300 Flower of Cone of Equisitites Williamsonia CORDAITALES AND CONIFERS Woody trunks, often rich in resin; Pages: leaves are needle-like, spirally 292–299 arranged. Male and female reproductive structures present on a single tree; Cone of Picea seeds in cones. Leaflets of Stem of Range Late Dicroidium Osmunda Carboniferous –Recent Pages: 301–306 GINKGOS AND ANGIOSPERMS Pages: 307–311 Preserved as wood, leaves, and, very Leaf of rarely, flowers, where both male and Araliopsoides female organs may be present. Seeds are large; leaves are deciduous, (some) Trunk of broad, with a radiating network of veins, Palmoxylon or relatively narrow with parallel veins. Range Cretaceous–Recent

32 | Invertebrates INVERTEBRATES FORAMINIFERANS FORAMINIFERANS ARE SMALL, single­ foraminiferans float in the surface celled organisms belonging to the waters of the oceans, their dead tests kingdom Protista. Some species secrete drifting down to the sea bed; benthonic a shell, called a test, made of calcium foraminiferans live in or on the sea carbonate or (less commonly) chitin. bottom. Both types occur in large Others construct a test by sticking numbers, and rocks may form from together particles of sand and debris. their remains. The few large species Most species live in the sea: planktonic live in warm, shallow waters. Group: ROTALIIDA Subgroup: NUMMULITIDAE Informal name: Nummulite Nummulites tiny internal chambers Circular in outline and biconvex, this large foraminiferan is made circular, up internally of small chambers biconvex arranged in a spiral. form HABITAT Nummulites was Nummulites ghisensis abundant in the shallow, (Ehrenberg); Nummulitic warm seas of the ancient Limestone: Eocene; Egypt. Tethys Ocean. Occurrence: REMARK Nummulitic limestone was used in the building of the Typical diameter Egyptian pyramids. 1.5cm (5⁄8in) Range: Paleocene–Oligocene Distribution: Europe, M. East, Asia Group: MILIOLIDA Subgroup: ALVEOLINIDAE Informal name: Alveolinid Alveolina Block of Alveolina Alveolina elliptica Oval in shape and often large in size, limestone (Sowerby); this creature is made up internally of Kithar Series; numerous small chambers, which in Eocene; India. life may have housed symbiotic algae. oval shape HABITAT Alveolina lived on the sea bed in warm, Typical diameter shallow waters. 4mm (5⁄32in) REMARK Where locally abundant, Alveolina sometimes formed limestones. Range: Eocene Distribution: Europe, M. East, Africa, Asia Occurrence:

Invertebrates | 33 SPONGES SPONGES ARE SIMPLE, sedentary, aquatic siliceous, or horny. Sponges occur animals. Water passes in through their as fossils from Cambrian times many surface pores to the central cavity onwards, and were abundant in of the sac-like body, and out through the Cretaceous. Stromatoporoids larger holes. The skeleton, where are also believed to be sponges, but present, is made up of needle-like archaeocyathids are now thought spicules, and is either calcareous, to be an independent phylum. Group: RETICULOSA Subgroup: DICTYOSPONGIIDAE Informal name: Glass sponge Hydnoceras vase-shaped body The thin-walled, vase-shaped Hydnoceras is a fine example of a glass sponge, with an open structure of spicules forming a rectangular meshwork. Bulbous swellings appear along the longitudinal ridges. HABITAT Living glass sponges are found only in deep rectangular water, but they were once common at all depths. meshwork REMARK This fossil is an internal mould in sandstone, preserving the filling of the skeleton but not the skeleton itself. The meshwork is clearly visible, but not the spicules themselves. bulbous swelling Typical height base Hydnoceras tuberosum 20cm (8in) Conrad; Upper Devonian; USA. Range: Late Devonian–Carboniferous Distribution: Eastern USA, Europe Occurrence: Group: LITHISTIDA Subgroup: KALIAPSIDAE Informal name: Calcisponge Laosciadia Laosciadia plana (Phillips); Upper This flat, mushroom-shaped sponge, common Chalk; Late in the Late Cretaceous, is a lithistid, a kind of Cretaceous; demosponge characterized by a compact, UK. complex structure with many chambers. The skeleton consists of a rigid upper interlocking framework of surface four-rayed spicules. rigid framework HABITAT These siliceous Typical height of spicules sponges lived in depths of 8cm (31⁄4in) water varying from I00 to holdfast 400m (330–1,300ft). Occurrence: Range: Cretaceous Distribution: Europe

34 | Invertebrates Group: LYCHNISCOSIDA Subgroup: VENTRICULITIDAE Informal name: Glass sponge Rhizopoterion top Rhizopoterion cribrosum (Phillips); Upper Chalk; This generally funnel-shaped genus Late Cretaceous; UK. is one of the glass sponges, or hexactinellids, which are very different side in their organization from other sponges wall found as fossils. Their siliceous skeletons have an open structure of spicules, with four rectangular to six rays mutually at right-angles, forming exhalant a rectangular meshwork. Within the glass canals sponges, ventriculitids form an important open meshwork group, of which Rhizopoterion is a member. of spicules They vary in form, but all are characterized by the form of their spicules, and by having walls Occurrence: pierced by an irregular array of slot-like inhalant and exhalant canals. Their bases have a holdfast of radiating “roots”, and they range in shape from tall, narrow vases to flat, open mushrooms. HABITAT Glass sponges, such as Typical height Rhizopoterion lived on muddy substrates 10cm (4in) down to a depth of 6,000m (20,000ft) or more. REMARK As indicated by its usual (but incorrect) name, Ventriculites infundibuliformis, this species is generally funnel-shaped. It occurs commonly in the Late Cretaceous (Chalk) of Europe. Range: Cretaceous Distribution: Europe Group: PHARENTRONIDA Subgroup: LELAPIIDAE Informal name: Calcisponge Raphidonema Raphidonema farringdonense This genus belongs to the separate class of (Sharpe); calcisponges, in which the skeleton is made Faringdon Sponge of calcareous, rather than siliceous, spicules. Raphidonema is irregularly Gravels; Early cup-shaped and very variable in size. Cretaceous; UK. Generally, the interior is smooth, while outside it is covered with main exhalant rounded, knobbly projections. opening HABITAT This calcareous sponge side wall lived in warm, shallow waters. Occurrence: REMARK This is the most common sponge found in the famous Faringdon Sponge Gravels at Faringdon, knobbly outside Oxfordshire, in the Typical height surface United Kingdom. 8cm (31⁄4in) Range: Triassic–Cretaceous Distribution: Europe

Group: ACTINOSTROMATIDA Subgroup: ACINOSTROMATIDAE Invertebrates | 35 Actinostroma Informal name: Stromatoporoid Actinostroma is a typical calcareous, reef concentric building, blob-like stromatoporoid. growth layers Although enigmatic, the genus is thought by some to be the ancestor of modern sclerosponges. When studied in thin section, it shows a fine structure of thin, concentric layers and radial pillars. HABITAT This genus commonly lived on, and formed, reefs. REMARK These organisms were important rock formers, particularly in the Silurian and Devonian. Typical height Actinostroma irregular shape 12cm (43⁄4in) clathratum Nicholson; Middle Devonian; UK. Range: Cambrian–Early Carboniferous Distribution: Worldwide Occurrence: Group: ARCHAEOCYATHIDA Subgroup: METACYATHIDAE Informal name: Archaeocyathid Metaldetes outer wall Metaldetes taylori (Bedford); Metaldetes is a widely distributed example Early Cambrian; of the group of marine animals known as Australia. archaeocyathids. Although sponges and archaeocyathids are unrelated, the latter septum have a similar calcareous (but non-spicular) (partition) skeleton. Metaldetes has basically a single or double-walled cone perforated by numerous pores. The central cavity is empty, as in sponges. It is not known how the soft tissue was organized. HABITAT These small Typical height inner wall empty central creatures lived in reefs 5cm (2in) cavity in warm, shallow seas. REMARK Most Occurrence: archaeocyathids are found silicified in hard limestones, and are known from the Early Cambrian of South Australia, Siberia, Sardinia, and Antarctica. Range: Cambrian Distribution: Worldwide

36 | Invertebrates BRYOZOANS BRYOZOANS ARE colonial animals shape – some are sheet-like encrustations which resemble miniature corals but on shells and stones, whereas others are more closely related to brachiopods. grow as small tree shapes or net-like They range from the Ordovician to the fronds. Each colony consists of a few to present day. Most bryozoans live on thousands of connected individuals the sea bed and secrete calcareous (zooids). Each zooid has a tubular or skeletons. Bryozoan colonies vary in box-shaped skeleton. Group: CYSTOPORATA Subgroup: CONSTELLARIIDAE Informal name: Sea mat bifurcating branch Constellaria star-shaped This bryozoan developed as a bushy colony monticule with thick, often compressed, branches. The branch surfaces are covered by distinctive Constellaria star-shaped monticules (regularly shaped antheloidea hummocks). Feeding zooids are located (Hall); Cincinnati along the rays of the stars. The monticules Group; Late of colonies probably formed chimneys for Ordovician; USA. the expulsion of exhalant feeding currents. HABITAT Constellaria lived on the sea bed. Typical branch diameter 1cm (3⁄8in) Range: Ordovician–Silurian Distribution: N. America, Europe, Asia Occurrence: Group: CRYPTOSTOMATA Subgroup: PTILODICTYIDAE Informal name: Sea mat Ptilodictya Ptilodictya lanceolata (Goldfuss); Wenlock This colony consists of a single branch, Limestone; Late straight or gently curved, and diamond- Silurian; UK. shaped in cross-section, with a median wall butting box-shaped zooids from associated both sides. The zooids are rectangular brachiopod in outline and arranged in longitudinal rows on the branch surface. At the pointed end of the branch is a conical structure, which fitted into a socket on the encrusting base of the colony and permitted the branch to articulate. HABITAT Ptilodictya lived in Tapering Typical length the sea with the encrusting branch end, 23cm (9in) base cemented to hard ground. articulated REMARK This specimen has by a socket a brachiopod lying next to it. Range: Ordovician–Devonian Distribution: Worldwide Occurrence:

Group: CRYPTOSTOMATA Subgroup: FENESTELLIDAE Invertebrates | 37 Fenestella Informal name: Lace corals branches linked This erect, net-like colony is formed of by dissepiments narrow, regularly spaced, branches linked by dissepiments. The zooids are arranged in oldest part two rows along the branches, with apertures of colony opening on one side only of the planar, folded, root-like spines or conical colonies. The dissepiments lack Occurrence: zooids. Spinose outgrowths have been Informal name: Sea mat developed, especially near the colony base, and were sometimes barbed. soft matrix HABITAT Fenestella and fractured similar reticulate bryozoans limestone end of lived by filtering food from matrix branch Occurrence: self-generated water currents, which flowed in one direction through the holes in the colony. Fenestella plebeia McCoy; Typical Carboniferous colony height Limestone; Early Carboniferous; UK. 5cm (2in) Range: Silurian–Permian Distribution: Worldwide Group: CYCLOSTOMATA Subgroup: CAVIDAE Ceriocava cylindrical branches This is a bushy colony with bifurcating cylindrical branches up to 5.5cm (2in) in diameter. The branch surfaces are covered by a honeycomb of polygonal (typically hexagonal) zooidal apertures, many sealed by lids. Long, sack-shaped polymorphic zooids for larval brooding are occasionally found. HABITAT This bryozoan formed low colonies on the sea floor, filtering food from the surrounding water. Typical branch Ceriocava diameter 3mm (1⁄8in) corymbosa Lamouroux; Bryozoan Range: Jurassic–Cretaceous limestone; Middle Jurassic; France. Distribution: Europe

38 | Invertebrates Group: TUBULIPORTA Subgroup: MULTISPARSIDAE Informal name: Sea mat Reptoclausa ridges on sediment trapped colony surface between ridges This encrusting colony is characterized by having long ridges aligned parallel to the direction of its growth. Ridge flanks and crests are occupied by feeding zooids with sub-circular apertures. Smaller, indistinct, non-feeding, polymorphic zooids form the smooth-surfaced valleys between the ridges. These zooids lack apertures. HABITAT These colonies were relatively robust, and capable of living on rolling stones and shells in turbulent marine conditions. sheet-like colony spreading over pebble Typical colony Reptoclausa hagenowi exposed surface diameter 4cm (11⁄2in) (Sharpe); Faringdon Sponge of dark grey pebble Gravel; Early Cretaceous; UK. Occurrence: Range: Jurassic–Cretaceous Distribution: Europe, Asia Informal name: Lace corals Group: RETEPORIDAE Subgroup: SERTELLIDAE zooids opening on Schizoretepora corrugated fronds branch surface This is a colony of complex, folded fronds pierced by oval fenestrules. Feeding zooids opened on one side of the fronds. They have apertures with sinuses. Defensive polymorphs (avicularia) are scattered over all branch surfaces. Schizoretepora is one of several similar genera that require careful microscopic study for accurate identification. HABITAT Schizoretepora lives on the sea bed. Schizoretepora notopachys (Busk); Coralline Crag; Pliocene; UK. Typical colony perforations cross-sections diameter 4cm (11⁄2in) Distribution: Worldwide of broken branches Range: Miocene–Recent Occurrence:

Group: Not applicable Subgroup: Not applicable Invertebrates | 39 Bryozoan limestone Informal name: Bryozoan limestone Some limestones consist predominantly of echinoid fragment fragments of the calcareous skeletons pieces of reticulate of bryozoan colonies. Many different bryozoans bryozoan species may be present, often accompanied by broken mollusc shells and barnacles. HABITAT Bryozoan limestones are especially common in the shallow­ water deposits of the Cenozoic Era. Today, they can be found forming in subtropical to cold­water environments, but bryozoan limestones are rarer in the tropics, where coral limestones are found in great abundance. branch fragments Width of rock bryozoan Bryozoan limestone; specimen 11cm (41⁄2in) encrusting a shell Miocene; Australia. Range: Jurassic–Recent Distribution: Worldwide Occurrence: Group: CHEILOSTOMATA Subgroup: CLEIDOCHASMATIDAE Informal name: Sea mat Hippoporidra gastropod shell monticule completely The thick, multilayered colonies encrust gastropod enveloped shells. The feeding zooids have frontal walls pierced by marginal pores, and apertures with a sinus. apex Atop the monticules are larger zooids, and scattered between the monticules are avicularia hermit crab larger with pointed rostra. aperture zooids on monticule HABITAT Recent Hippoporidra live symbiotically with hermit crabs, providing the crabs with Hippoporidra edax excellently camouflaged homes. Although (Busk); James River the crabs are not preserved Formation; as fossils, palaeontologists Pleistocene; USA. believe the bryozoan colony­form is diagnostic outer lip of their past presence. Typical length 2cm (3⁄4in) Range: Miocene–Recent Distribution: Europe, N. America, Africa Occurrence:

40 | Invertebrates WORMS WORM IS A GENERAL NAME applied to some members of the polychaeta representatives of various soft-bodied group of segmented worms secrete invertebrate groups. They include the a dwelling tube made of durable platyhelminthes, nematodes, nemertines, calcite, which is often found attached acanthocephalans, annelids, and some to fossil shells or pebbles. These are hemichordates. Most are unknown or common fossils in certain Mesozoic very rare in the fossil record. However, and Cenozoic rocks. Group: SABELLIDA Subgroup: SERPULIDAE Informal name: Serpulid worm Proliserpula Proliserpula ampullacea (J. Sowerby); Upper Chalk; The tube of this worm is always attached to a hard Late Cretaceous; UK. substrate, often a fossil shell like the sea urchin circular opening for shown here. It coils in an irregular spiral, with tentacles a single narrow ridge running along the spiral growth form mid-line. The aperture is circular, and tube Occurrence: the sides display prominent growth lines. Informal name: Serpulid worm HABITAT This genus is found only in the deeper waters of the chalk seas. Rotularia bognoriensis REMARK There was great (Mantell); London Clay; competition for hard surfaces to Early Eocene; UK. encrust, and other species have attached themselves to this shell. Typical length 5cm (2in) Range: Late Cretaceous Distribution: Europe Group: SABELLIDA Subgroup: SERPULIDAE Rotularia coiled tube The ridged living tube of Rotularia is tightly coiled in a flat spiral, and slightly concave on one side and convex on the other. The last-formed part of the tube stands erect, like the tip of a fireman’s hose. HABITAT This form was free-living on sandy substrates in a shallow marine environment. The dense aggregation of individuals in this specimen was probably caused by storm waves. Typical diameter concave face convex face 1.5cm (5⁄8in) Distribution: Europe Occurrence: Range: Eocene

Group: SABELLIDA Subgroup: SERPULIDAE Invertebrates | 41 Serpula Informal name: Serpulid worm The tube of this serpulid worm is elongated and rounded in Serpula indistincta (Fleming); cross-section, tapering slowly to a fine point. It may be gently Carboniferous Limestone; curved or sharply bent, with a relatively thin wall, ornamented Early Carboniferous; UK. by irregular growth lines. It has a rounded aperture. limestone HABITAT Although this genus matrix was not cemented to the substrate, it was not actually mobile. rounded aperture narrow part of tube, formed first Typical length Distribution: Worldwide growth 5cm (2in) lines Occurrence: Range: Palaeozoic–Recent Informal name: Serpulid worm Group: SABELLIDA Subgroup: SERPULIDAE Glomerula plexus (J. Sowerby); Upper Chalk; Glomerula Late Cretaceous; UK. The narrow, rounded tubes of Glomerula grew in broken end an irregular, twisting fashion. Tubes from different of tube individuals intertwined, so that the whole group eventually resembled a badly rolled ball of broken twisted string. In proportion to the thick wall of the tube, form of the aperture is actually quite narrow. tubes HABITAT A large number of individuals made up a single group, which lived unattached on the sea bed. This intertwined habit allowed it this freedom. REMARK Like most serpulids, Glomerula fed by filtering particles of organic debris and plankton from the sea. Typical length individual tubes 10cm (4in) intertwined Range: Early Jurassic–Paleocene Distribution: Worldwide Occurrence:

42 | Invertebrates TRACE FOSSILS TRACE FOSSILS ARE the remains of by their constructor. Ichnogenera and structures made by animals, preserved ichnospecies, from the Greek word in sedimentary rock. They include ichnos (trace), are the usual classifications, tracks, trails, borings, and burrows. but fossils may also be classified by Since different organisms are able to their cause, i.e. feeding, crawling, make the same trace, trace fossils are dwelling, etc., and hence fodinichnia, classified by their shape, rather than repichnia, dominichnia. Group: Unclassified Subgroup: FODINICHNIA Informal name: Trace fossil Chondrites Chondrites sp.; Late Cretaceous; Spain. This small burrow superficially resembles a plant root, as it comprises mudstone a central tube, from the base of which matrix numerous, subdividing branches radiate out. The animal most likely single central tube to have constructed these burrows Occurrence: is a nematode worm (roundworm). HABITAT Chondrites is branching, sediment- found in marine sediments, filled burrows and is especially common in sediment formed in conditions of reduced oxygen. Variable length Range: Triassic–Recent Distribution: Worldwide Group: Unclassified Subgroup: REPICHNIA Informal name: Trace fossil Cruziana sandstone infill of double preservation groove This trace has a two-lobed structure with a central groove – the hardened infill of a double groove excavated on the sea floor. The lobes are covered with scratch marks made by the legs of the excavating organism, usually a trilobite. HABITAT Cruziana is most common in marine sediments from the Palaeozoic era. Variable length Cruziana sp.; scratch mark made by leg Nubian sandstone; Occurrence: Cambrian; Egypt. Range: Cambrian–Triassic Distribution: Worldwide

Invertebrates | 43 PROBLEMATICA SOME FOSSILS CANNOT be placed have been variously classified as into major groups of animals or plants worms, soft corals, jellyfish, etc. with any certainty. Often this is because However, the true identity of these they represent only a small, obscure part ancient fossils remains a subject of of an organism, but there are others, controversy – some may even be from Ediacaran sediments, that have trace fossils – and they are best completely preserved forms. These treated as Problematica. Group: Unclassified Subgroup: Unclassified Informal name: Trace fossil Mawsonites Mawsonites spriggi Glaessner & Wade; This large fossil has a circular outline, Ediacara sandstone; broken into irregular lobes. The Ediacaran; Australia. surface carries irregular lobe- or scale-shaped bosses arranged irregular, concentrically, with a central, lobed margin button-like swelling. Originally concentric interpreted as a jellyfish, it is now lobes thought this form may have been a radiating burrow system, central, and thus a trace fossil. button-like protuberance HABITAT This Typical length structure could have 13cm (5in) Occurrence: been made by an organism hunting Informal name: Sea pen through silt for food. Charniodiscus Range: Ediacaran Distribution: Australia masoni (Ford); Woodhouse Beds; Group: PENNATULACEA Subgroup: CHARNIIDAE Ediacaran; UK. Charniodiscus central axis This is a feather-shaped fossil attached to a basal disc (not present on this specimen). Closely spaced alternate branches diverge from a central axis, with each branch subdivided by about 15 transverse grooves. HABITAT This animal lived attached to side the sea floor, feeding by filtering nutritious branches particles from the water. REMARK The affinities of Charniodiscus transverse Typical length remain uncertain, but most palaeontologists grooves 20cm (8in) consider it to be a type of soft coral. One theory suggests it is a representative of a distinct group of organisms, the Vendozoa. Range: Ediacaran Distribution: Australia, Europe Occurrence:

44 | Invertebrates Group: Unclassified Subgroup: Unclassified Informal name: Unclassified Spriggina Spriggina floundersi Glaessner; Ediacara The body of Spriggina is elongated, tapering to a point at the rear, Sandstone; Ediacaran; similar to a tail. The broader front end is rounded, and consists of a Australia. narrow, crescent-shaped arc. The rest of the body is divided along its length by a central line, and transversely into short, broadly pointed V-shaped segments. “tail” end HABITAT Spriggina lived in a shallow, sandy, marine habitat. REMARK This form was first thought to be a worm, then an early arthropod or part of a new group, neither plant nor animal. Typical length crescent- V-shaped 7cm (23⁄4in) shaped segments “head” Occurrence: Range: Ediacaran Distribution: Australia, Africa, Russia Group: CONULARIIDA Subgroup: CONULARIIDAE Informal name: Conularid Paraconularia Paraconularia derwentensis This shell is conical and four-sided, but rhombic (Johnston); Early in cross-section. Each of the four sides carries Permian; Australia. upwardly arched, closely spaced growth lines, and at each of the four corners is a shallow V-shaped tentacled groove. The shell itself is thin, and made of end in the phosphatic and proteinaceous material. living animal HABITAT This species lived in shallow to deep marine waters, attached to the sea bed by a small basal disc. growth REMARK Members of this family have been variously lines placed in the molluscs, in a new group related to the worm-like phoronids, or most commonly with the jellyfish, because of the supposed tentacles sometimes preserved. The tentacles may have been used to catch small marine animals, stinging in the same way as sea anemones. Range: Early Permian Typical length broken 10cm (4in) base Distribution: Australia Occurrence:

Invertebrates | 45 GRAPTOLITES GRAPTOLITES ARE AN extinct group or more branches (stipes), originating of colonial organisms that lived from from an individual (sicula). Each the Cambrian to the Carboniferous. subsequent individual was housed Their remains can be mistaken for fossil within a tubular structure (theca). plants as they sometimes resemble Geologists find graptolites especially fossilized twigs. Each colony had one useful in dating rocks. Group: GRAPTOLOIDEA Subgroup: RETIOLITIDAE Informal name: Graptolite Retiolites reduced base of colony skeleton The thecae of Retiolites are arranged in two series lying back to back, forming a single stipe, which gradually expands in width away from the proximal end. The organic- walled skeleton of Retiolites had a characteristic open network which presumably made it lighter in the water. HABITAT Retiolites probably Typical length Retiolites geinitzianus had a free-floating existence. 3cm (1in) (Barrande); Graptolite shales; REMARK Free-floating Silurian; Czech Republic. graptolites, such as Retiolites, make good zonal fossils. Range: Silurian Distribution: Worldwide Occurrence: Group: GRAPTOLOIDEA Subgroup: DICHOGRAPTIDAE Informal name: Graptolite Phyllograptus Phyllograptus typus Hall; Levis shale; Early This colony comprised four series of thecae Ordovician; Canada. arranged back-to-back in a cross-like formation. Usually, due to compression, Occurrence: only a pair of thecae are clearly visible on shale specimens. The thecae are long and curved with small apertural lips. The generic name, Phyllograptus, refers to the leaf-like appearance of these flattened colonies. HABITAT Phyllograptus floated freely in the open ocean. Typical length shale matrix 3.5cm (12⁄5in) Range: Early–Middle Ordovician Distribution: Worldwide

46 | Invertebrates Group: GRAPTOLOIDEA Subgroup: DICHOGRAPTIDAE Informal name: Graptolite two Expansograptus extended stipes These were small to large graptolites with approximately sicula twenty to several hundred thecae. Occurrence: Two stipes diverge from the initial sicula, which is distinguished by Informal name: Graptolite its dorsally projecting nema (an extension of the initial sicula) at Typical length the point where the thecae of the 20cm (8in) two stipes diverge. The thecae are Occurrence: usually of relatively simple type, tubular or with a small apertural lip. The different species are distinguished by the number of thecae per centimetre, and the width and shape of the stipes. HABITAT Expansograptus floated in open seas. Expansograptus cf. nitidus (Hall); Mytton Formation; Early Ordovician; UK. Typical length 5cm (2in) Distribution: Worldwide Range: Early–Middle Ordovician Group: GRAPTOLOIDEA Subgroup: DICHOGRAPTIDAE Loganograptus These were large graptolites: the rapid initial dichotomies near the sicula produced a colony with sixteen stipes. These stipes were evenly separated in life, but frequently bent in fossils. The thecae are simple tubes – about one per millimetre. HABITAT This genus lived in the deeper parts of the Ordovician ocean. Loganograptus logani (Hall); Skiddaw Group; Early thecae slowly increase Ordovician; UK. in size along stipes Range: Early Ordovician Distribution: Worldwide

Group: GRAPTOLOIDEA Subgroup: DICHOGRAPTIDAE Invertebrates | 47 Tetragraptus fissile shale Informal name: Graptolite partially This graptolite had four stipes of visible sicula variable form – they may have been reclined, or outstretched Occurrence: horizontally. Some species had Informal name: Graptolite a web-like structure connecting the four stipes. The thecae are carbonized usually of simple, tubular form, periderm and may be inclined at high or low angles. Stipes vary in width from 1 to 10mm (1⁄25–2⁄5in). HABITAT Tetragraptus floated widely in Early Ordovician seas. tubular thecae Tetragraptus quadribrachiatus (Hall); Skiddaw Group; Early Ordovician; UK. Typical length l0cm (4in) Range: Early Ordovician Distribution: Worldwide Group: GRAPTOLOIDEA Subgroup: DIPLOGRAPTIDAE Orthograptus mudstone Orthograptus was a biserial graptolite, which means that it had two series of thecae lying back-to-back, producing a robust, double-edged colony. The proximal growth of the colony is a crucial identification feature. Orthograptus had a strongly developed spine. The thecal apertures were moderately straight. The variations in colony size, width, and thecal form determine the species. HABITAT This graptolite is robust possibly epiplanktonic, and colony floated in very shallow seas. Typical length Orthograptus Occurrence: 8cm (3in) intermedius (Elles); Bifidus Beds; Early Range: Middle–Late Ordovician Ordovician; UK. Distribution: Worldwide

48 | Invertebrates Subgroup: MONOGRAPTIDAE Informal name: Graptolite Group: GRAPTOLOIDEA Monograptus isolated distal thecae triangulate thecae Graptolites of this genus had a single stipe and a highly variable form; they could be completely straight, gently curved, or completely spiral. The form of the thecae is vital to identification. In this genus there was a tendency for thecae to become isolated from one another. Some evolved very rapidly, so species of this genus are easily recognizable and stratigraphically useful. HABITAT It floated in open seas. Monograptus convolutus Hisinger; Silurian Flags; Silurian; UK. Typical diameter 20cm (8in) Range: Silurian–Early Devonian Distribution: Worldwide Occurrence: Group: GRAPTOLOIDEA Subgroup: DICHOGRAPTIDAE Informal name: Graptolite Didymograptus siculae at pointed ends These graptolites formed a shape similar to a “tuning fork”. The colonies were often robust, ranging in size from 1cm to 10cm (3⁄8in to 4in). The thecae are long with simple tubes. The stipes expand in width from the proximal end. HABITAT This genus floated in northern oceans. Didymograptus murchisoni (Beck); Llanvirn Series; Early Ordovician; UK. dark shale Typical length Distribution: Worldwide mineralized 10cm (4in) periderm Range: Early–Middle Ordovician Occurrence:

Group: GRAPTOLOIDEA Subgroup: RHABDINOPORIDAE Invertebrates | 49 Informal name: Graptolite Rhabdinopora triangulate thecae The genus Rhabdinopora, originally known as Dictyonema, is characterized by its conical form and small thecae. lt had numerous branches arising from the sicula. The branches are connected by dissepiments giving a reticulate appearance (such dissepiments were lost on later graptoloids). HABITAT This fossil genus is commonly found in masses, and is believed to be the earliest planktonic graptolite. Typical length fan-like Rhabdinopora 6cm (21⁄2in) colonies socialis (Salter); Dictyonemaskiffern; Range: Early Ordovician Early Ordovician; Norway. Distribution: Worldwide, except Antarctica Occurrence: Group: GRAPTOLOIDEA Subgroup: MONOGRAPTIDAE Informal name: Graptolite Rastrites curved Rastrites magnus stipe (Mattock); Deep-water The colony was thin and delicate shales; Silurian; UK. with comparatively few thecae. It had a single, elegantly curved stipe. The thecae were developed as long, isolated, and narrow tubes with a restricted aperture. Such species could not survive turbulence. HABITAT Rastrites lived in open oceans. They are characteristic of black shales. black shale Typical length Distribution: Worldwide long thecae 4cm (11⁄2in) Occurrence: Range: Silurian

50 | Invertebrates CORALS CORALS ARE MARINE ANIMALS with a tube-like features (corallites), often divided sac-like body (polyp), mouth, tentacles, by simple transverse partitions (tabulae) and skeleton. The polyp occupies a or by series of plates (dissepiments), or circular, polygonal, or elongate cavity both. Polyps may divide to form colonies, (calice), which is generally surrounded by with corallites sometimes joined by a wall. Calices are usually divided by intercorallite structures (coenosteum). star-like arrangements of plates (septa), There are three main coral groups, which sometimes have a central structure. two extinct (Rugosa, Tabulata), and The calice wall, if present, forms horn- or one extant (Scleractinia). Group: CYSTIPHYLLIDA Subgroup: GONIOPHYLLIDAE Informal name: Rugose coral angular Goniophyllum corallite This coral is usually solitary. It has a square short septa to quadrilateral transverse section and a lid-like structure of four plates (sometimes Goniophyllum missing). The calice is deep and the short pyramidale Hisinger; septa bear distinctive flanges. There are Silurian; Sweden. numerous internal dissepimental plates. Occurrence: HABITAT Goniophyllum lived in shallow-water limestones and muds. Typical calice diameter 1.5cm (5⁄8in) Range: Early–Middle Silurian Distribution: Europe, N. America Group: STAURIIDA Subgroup: ZAPHRENTIDAE Informal name: Rugose coral Heliophyllum horn-shaped Heliophyllum sp.; corallite Hamilton Formation; A solitary, sometimes colonial, coral, with open branched Middle Devonian; or adjoined corallites. The calice is shallow with long rejuvenating Canada. septa, sometimes reaching the centre of the corallite. calice Dissepiments are numerous, small, well-rounded, and confined to the outer zone of corallite. The central zone is occupied by flat or slightly curved tabulae. The external walls are thin with fine growth ridges. HABITAT Heliophyllum inhabited shallow water. fine growth ridges Typical calice Distribution: Worldwide, except Asia Occurrence: diameter 2cm (3⁄4in) Range: Devonian