The Burgess Shale

Fossils from the Walcott Quarry

Some groups have more species and specimens than others. Below is a detailed breakdown of the species from the Walcott Quarry belonging to these main groups. Species with mineralized parts are emphasized in bold – these are the only ones that could have been fossilized under normal conditions, rather than the special conditions leading to Burgess Shale-type preservation. Details and illustrations of most species listed below are illustrated in the Fossil Gallery.

Algae and bacteria

Algae: This group consists of eukaryotic organisms that usually depend on light as their source of energy. In the Walcott Quarry, both green and red algae have been identified, but many species are probably just preservational or morphological variants of a small number of taxa. Most have yet to be studied in any detail.

12 species: Bosworthia gyges, Bosworthia simulans, Dalyia nitens, Dalyia racemata, Dictyophycus gracilis, Margaretia dorus, Sphaerocodium? cambria, Sphaerocodium? praecursor, Wahpia mimica, Wahpia virgata, Waputikia ramosa, Yuknessia simplex.

Margaretia dorus
Margaretia dorus.

Cyanobacteria: This is a group of prokaryotic microorganisms that depend on light for their source of energy. In the Walcott Quarry, there are at least two different species, one forming tufts (Marpolia), the other forming sheet-like structures at the sea bottom (Morania). Walcott briefly described 8 species of Morania, but as is the case with the algae, many of these are probably just preservational variants and have yet to be restudied in detail.

9 species: Marpolia spissa, Morania confluens, Morania elongata, Morania fragmenta, Morania? frondosa, Morania? globosa, Morania parasitica, Morania? reticulata.

Marpolia spissa
Marpolia spissa.


Annelida: These elongated, many-segmented animals are represented today by the common terrestrial earthworms and leeches, marine-swimming animals (“polychaetes”) including bristle worms, and several smaller groups. The annelid body is covered by a thin flexible cuticle that is not moulted during growth. Each major group has a characteristic segment construction; in annelid bristle worms, segments bear a prominent pair of lateral flap-like structures called parapodia that are mainly used for locomotion. Various numbers of “bristles” (chaetae) are organized in bundles along the parapodia and help with movement. Many fossil annelids from the Burgess Shale show exquisite preservation of parapodia and bristles. Based on the morphology of these elements, some were interpreted as active swimmers (e.g., Canadia), while others probably lived in or on the mud at the bottom of the sea (e.g., Peronochaeta). These Burgess Shale taxa are not currently thought to belong to the modern forms of bristle worms, and have most recently been reinterpreted as stem group annelids.

5 species: Burgessochaeta setigera, Canadia spinosa, Insolicorypha psygma, Peronochaeta dubia, Stephenoscolex argutus.

Canadia spinosa.

Arthropoda: Today, arthropods are the most diverse of all animal groups, a distinction they have probably held since the Cambrian. Characterized by a segmented body, a rigid external cuticular covering (the exoskeleton), and jointed limbs, this group is represented by the modern spiders, shrimps, insects, and millipedes. It also includes the now-extinct trilobites. Arthropods grow by shedding their exoskeleton (a process called moulting), which can harden or even mineralize in some cases (such as in crabs and trilobites). The Burgess Shale contains a wide range of fossil arthropod morphologies, many representing various stem groups of particular subgroups within the arthropods. Others, for example Opabinia and Anomalocaris, are considered more primitive and cannot be considered true arthropods (Euarthropoda). These species might represent early stem groups along the lineage leading to true arthropods. Fossil arthropods found in the Walcott Quarry show adaptation to a wide range of habitats and ecologies; they include carnivores and deposit feeders, swimmers, walkers, and probably burrowers.

53 species: Alalcomenaeus cambricus, Anomalocaris canadensis, Branchiocaris pretiosa, Burgessia bella, Canadaspis perfecta, Caryosyntrips serratus, Chancia palliseri, Ehmaniella burgessensis, Ehmaniella waptaensis, Elrathia permulta, Elrathina cordillerae, Emeraldella brocki, Habelia brevicauda, Habelia optata, Hanburia gloriosa, Helmetia expansa, Houghtonites gracilis, Hurdia victoria, Isoxys acutangulus, Isoxys longissimus, Kootenia burgessensis, Laggania cambrica, Leanchoilia persephone, Leanchoilia protogonia, Leanchoilia superlata, Liangshanella burgessensis, Marrella splendens, Molaria spinifera, Mollisonia rara, Mollisonia symmetrica, Naraoia compacta, Naraoia spinifer, Odaraia alata, Olenoides serratus, Opabinia regalis, Oryctocephalus burgessensis, Oryctocephalus matthewi, Pagetia bootes, Perspicaris dictynna, Perspicaris recondita, Plenocaris plena, Priscansermarinus barnetti, Ptychagnostus praecurrens, Sarotrocercus oblita, Sidneyia inexpectans, Skania fragilis, Tegopelte gigas, Thelxiope palaeothallasia, Tuzoia retifera, Tuzoia burgessensis, Waptia fieldensis, Worthenenella crepidulus, Yohoia tenuis.

Naraoia compacta
Naraoia compacta.

Brachiopoda: Brachiopods are bottom-dwelling (benthic) marine suspension-feeding animals enclosed in a two-part shell. Most forms attach to a surface – the sea floor or other organisms – via a flexible cylindrical organ called a pedicle. Brachiopods first appeared in the Early Cambrian and were very important constituents of the sea-floor ecosystem throughout the Palaeozoic Era. Although some species still survive, the phylum was hit hard by the Late Permian mass extinction (about 250 million years ago). Most brachiopod shells are well-mineralized, and they consequently have a good fossil record. In the Burgess Shale, some stem group forms are preserved with soft-tissues, including their pedicles, setae (long, needle-like structures) and traces of the internal body organs. One Burgess Shale species (Acanthrotretella spinosa) has non-mineralized valves.

7 species: Acanthrotretella spinosa, Acrothyra gregaria, Diraphora bellicostata, Lingulella waptaensis, Micromitra burgessensis, Nisusia burgessensis, Paterina zenobia.

Micromitra burgessensis.

Chordata: Chordates are a group of animals united by the possession of a notochord and a dorsal nerve cord. In addition to the vertebrates (including humans) with their defining backbone and spinal column, chordate subgroups also include a number of minor taxa. Some chordates are attached to a surface – usually the sea floor – for at least part of their life, but most are mobile organisms. Pikaia gracilens from the Burgess Shale probably represents a very primitive (stem-group) form of chordates. Well-preserved fossils indicate it was an active swimmer. A second Burgess Shale stem-group chordate species is known only from two poorly preserved specimens.

2 species: Metaspriggina walcotti, Pikaia gracilens.

Pikaia gracilens.

Cnidaria: These radially-symmetrical animals have a simple body organization and two basic life modes: the swimming, jellyfish-like medusae, and sessile, polyp-like forms. The group includes modern corals and jellyfish. Various tubular fossils from the Walcott Quarry have been attributed to primitive sessile cnidarians, but until better details of their soft-tissue structures are found, such conclusions will remain provisional. Mackenzia is the only form not to have inhabited a tube; this soft-bodied, seabed-dwelling animal has been compared to living sea anemones.

4 species: Cambrorhytium fragilis, Cambrorhytium major, Mackenzia costalis, Tubullela flagellum.

Cambrorhytium fragilis.

Ctenophora: Ctenophores are radially organized animals with a simple body plan superficially resembling that of cnidarian jellyfish. Living representatives of this group are termed “comb jellies” because they have 8 comb-like rows of cilia (cilia are small elongated extensions of cells which can reach up to 2 millimetres in modern ctenophores) to propel them through the water. The fossil species from the Walcott Quarry have more comb rows than modern ctenophores and probably represent very primitive (stem-group) forms.

2 species: Ctenorhabdotus capulus, Fasciculus vesanus.

Ctenorhabdotus capulus
Ctenorhabdotus capulus.

Echinodermata: The echinoderms form a distinctive group of mostly benthic animals (living in, on or just above the sea floor). They are characterized by a multi-element mineralized skeleton with a peculiar microstructure (stereom). Almost all adult echinoderms exhibit fivefold (pentameral) symmetry (i.e., the body is organized into five radially similar sections). Living subgroups include the sea stars, sea urchins, and sea lilies (crinoids). Only stem-group echinoderms are found in the Burgess Shale, where they are relatively rare.

4 species: Echmatocrinus brachiatus, Gogia stephenensis, Walcottidiscus typicalis, Lyracystis reesei.

Echmatocrinus brachiatus.

Hemichordata: Hemichordates are a group of elongate animals with bodies composed of three main parts: a proboscis (mouthpart), collar, and trunk. Two major sub-groups are known, the worm-like enteropneusts and the diminutive and colonial pterobranchs. Primitive members of both groups are probably represented in the Walcott Quarry, but these species have not yet been described in detail.

3 species: Chaunograptus scandens, Oesia disjuncta, “Ottoia tenuis”.

Chaunograptus scandens.

Mollusca: A large group of animals, today characterized by a cavity-forming mantle. Modern molluscs include snails, squids, and clams. Fossils of several swimming and bottom-dwelling soft-bodied forms are known in the Walcott Quarry – these are considered to be basal stem-groups molluscs. Scenella is the only form with a mineralized shell.

5 species: Nectocaris pteryx, Odontogriphus omalus, Orthrozanclus reburrus, Scenella amii, Wiwaxia corrugata.

Odontogriphus omalus.

Onychophora (Lobopoda): Worm-like animals with unspecialized pairs of non-jointed limbs, the modern onychophorans (velvet worms) are all terrestrial. The two fossil species known in the Walcott Quarry are not true onychophorans, but probably belong within the lobopods, a stem-group of organisms more closely related to arthropods.

2 species: Aysheaia pedunculata, Hallucigenia sparsa.

Aysheaia pedunculata
Aysheaia pedunculata.

Porifera: The Porifera (or sponges) are among the most primitive animals; their simple body is not organized into true tissues. Sponges are mostly bottom-dwelling suspension feeders, and many forms possess a supporting mesh-work of fine needle-like spicules composed of various minerals. Several different types of fossil sponges are found in the Walcott Quarry, representing all major modern groups as well as potential stem-groups. Many of these have a low preservation potential, but isolated mineralized spicules of some taxa (in bold) are known in other Cambrian fossil deposits that do not preserve soft-tissues.

34 species: Capsospongia undulata, Choia carteri, Choia ridleyi, Crumillospongia biporosa, Crumillospongia frondosa, Diagoniella cyathiformis, Diagoniella hindei, Eiffelia globosa, Falospongia falata, Halicondrites elissa, Hamptonia bowerbanki, Hazelia conferta, Hazelia crateria, Hazelia delicatula, Hazelia dignata, Hazelia lobata, Hazelia luteria, Hazelia nodulifera, Hazelia obscura, Hazelia palmata, Leptomitus lineatus, Leptomitus undulatus, Moleculospina mammilata, Petaloptyon danei, Pirania muricata, Protospongia hicksi, Takakkawia lineata, Vauxia bellula, Vauxia densa, Vauxia irregulara, Vauxia gracilenta, Vauxia venata, Wapkia elongata, Wapkia grandis.

Choia ridleyi.

Priapulida: Predatory marine worms with a large, hook-lined anterior feeding organ called a proboscis, priapulids are relatively rare today. Priapulid-like animals were abundant in Cambrian communities; species found in the Walcott Quarry, including tube-dwelling forms, are probably stem-group priapulids.

5 species: Ancalagon minor, Fieldia lanceolata, Louisella pedunculata, Ottoia prolifica, Selkirkia columbia.

Selkirkia columbia.

Other known animals of uncertain affinities:

10 species: Allonnia sp., Amiskwia sagittiformis, Chancelloria eros, Dinomischus sagittiformis, Eldonia ludwigi, Haplophrentis carinatus, Herpetogaster collinsi, Pollingeria grandis, Portalia mira, Thaumaptilon walcotti.

Portalia mira
Portalia mira.

Gould Slideshow

In 1990, noted palaeontologist Stephen Jay Gould spoke at the Royal Ontario Museum about the fossils of the Burgess Shale. While many of Gould’s interpretations have been challenged, his talk provides a snapshot of how the organisms were viewed then. (6:20)

So this is Marrella. I should say that arthropods are classified primarily by numbers of segments and patterns in their various body parts.

Photograph of Marrella
DESCRIPTION: Photograph of Marrella

And here’s Marrella, it’s an arthropod that doesn’t fit into any group. It has these two sets of spines… there it is. It doesn’t have any allegiance.

Drawing of Marrella
DESCRIPTION: Drawing of Marrella

So Whittington was puzzled when he first published on Marrella in 1971 but he went on and the next creature he studied was Yohoia.

Photograph of Yohoia
DESCRIPTION: Photograph of Yohoia

Looked like a shrimp, had been called one by Walcott, and again, as Whittington studied it with care, it just didn’t fit into any modern group. It looks like a shrimp superficially, but when you start counting the segments you don’t have anything like the crustacean body plan.

Drawing of Yohoia
DESCRIPTION: Drawing of Yohoia

For instance, up in the head you have this unique set of frontal appendages which have no homologue anywhere else in the arthropods. Whittington ended up calling them simply “the great appendages” because he didn’t know what to do with them.

Photograph of Odaraia
DESCRIPTION: Photograph of Odaraia

This is Odaraia, a creature that swims on its back and has a tail fluke that looks more like a whale than an arthropod, but again, not allied to anything.

Drawing of Odaraia
DESCRIPTION: Drawing of Odaraia

Looked vaguely like a swimming crustacean, but isn’t when you look at the segments and their patterns of the tail.

Photograph of Sidneyia
DESCRIPTION: Photograph of Sidneyia

This is Sidneyia, which was described by Walcott as a chelicerate, that is a member of the horseshoe crab, eventually the spider-scorpion group. And in some superficial sense that’s what it looks like. But in detail it isn’t.

Drawing of Sidneyia
DESCRIPTION: Drawing of Sidneyia

All chelicerates have six pairs of appendages on their head. Sidneyia has one pair. It’s not like anything… just these antennae… it’s not like anything else… it is just is what it is.

Photograph of Habelia
DESCRIPTION: Photograph of Habelia

This is Habelia, an odd creature…

Drawing of Habelia
DESCRIPTION: Drawing of Habelia

… with tubercules all over its body.

Photograph of Leanchoilia
DESCRIPTION: Photograph of Leanchoilia

This is Leanchoilia, my personal favourite for elegance, but not among the survivors.

Drawing of Leanchoilia
DESCRIPTION: Drawing of Leanchoilia

Again, these odd great appendages, as Whittington calls them, with their whiplash endings.

Photograph of Aysheaia
DESCRIPTION: Photograph of Aysheaia

This is Aysheaia.

Drawing of Aysheaia
DESCRIPTION: Drawing of Aysheaia

Now, this creature is probably an onychophore, that is it is a member of a modern group symbolized by the genus with the wonderful name Peripatus, which is a not very well known group, but it’s thought to be possibly intermediary between annelids and arthropods and may be the ancestor of the insect group. So here we may have a creature that is truly related to one of the surviving groups of arthropods.

Desmond Collins, former ROM Curator, holding fossil
DESCRIPTION: Desmond Collins, former ROM Curator, holding fossil

And here is a form that Des Collins found and initially gave a field name, following paleontological tradition…

Photograph of Sanctacaris
DESCRIPTION: Photograph of Sanctacaris

… he called it “Santa Claws”. And eventually named it Sanctacaris, which means much the same thing. Now again, does it look any different than the ones I just showed you?

Drawing of Sanctacaris
DESCRIPTION: Drawing of Sanctacaris

Would you have picked out this creature for success? Could you have predicted that this, by virtue of superiority would go on? Yet it looks as though Sanctacaris really is a chelicerate.

There are six pairs of appendages in the right place on the head so this animal may be at least a cousin to one of the successful lineages. Again, would you have known? Could anyone have known?

Photograph of Opabinia
DESCRIPTION: Photograph of Opabinia

This is OpabiniaOpabinia, I think, should stand as one of the great moments in the history of human knowledge.

Drawing of Opabinia
DESCRIPTION: Drawing of Opabinia

Because Opabinia, which was described as an arthropod, a shrimp-like creature, by Walcott, who shoehorned it into modern groups as he always did. Opabinia was the first creature re-studied by Whittington that broke the conceptual dam, so to speak, and gave insights into this new world.

Technical drawing of Opabinia
DESCRIPTION: Technical drawing of Opabinia

Because Whittington began his studies in the early 1970s on Opabinia thinking it would be an arthropod. He realizes, as Walcott did not, that there was some three-dimensionality in these creatures, that they were not just films on the rock.

Photograph of Opabinia
DESCRIPTION: Photograph of Opabinia

That he could therefore dissect through and find structures underneath. So he said “Now I can resolve this, I’ll dissect through the body and find the appendages underneath which will prove its arthropod nature. He dissected through and he found nothing. There are no appendages.

Technical drawing of Opabinia
DESCRIPTION: Technical drawing of Opabinia

And as he reconstructed Opabinia, he came to understand it is not an arthropod, it is some bizarre creature of its own unique anatomy. And in publishing a monograph on Opabinia in 1975 I think you have the breakthrough point in the new interpretation of the Burgess Shale.

Drawing of Opabinia
DESCRIPTION: Drawing of Opabinia

Here is Marianne’s picture of Opabinia, a bizarre creature with five-count them, five-eyes, this vacuum-cleaner like nozzle with a food-collecting device in front, this bellows-like apparatus behind, followed by a tail. I don’t know what it is. It’s just weird.

Photograph of Nectocaris
DESCRIPTION: Photograph of Nectocaris

This is Nectocaris, a peculiar creature that looks like a chordate behind, combined with a fin ray…

Drawings of Nectocaris
DESCRIPTION: Drawings of Nectocaris

… and more like an octopod in the front. Who knows?

Photograph of Dinomischus
DESCRIPTION: Photograph of Dinomischus

This is Dinomischus, a peculiar, stalked, stemmed creature…

Drawing of Dinomischus
DESCRIPTION: Drawing of Dinomischus

… with no known affinity to anything else.

Photograph of Odontogriphus
DESCRIPTION: Photograph of Odontogriphus

This is Odontogriphus, literally meaning “the toothed mystery” a good name.

Drawings of Odontogriphus
DESCRIPTION: Drawings of Odontogriphus

A flat, gelatinous, annulated creature with a row of tooth-like structures surrounding a mouth and a pair of sensory palps.

Photograph of a fossil originally interpreted as a jellyfish
DESCRIPTION: Photograph of a fossil originally interpreted as a jellyfish

Walcott described three separate genera which he allocated, as was his wont, according to the shoehorn, into three conventional groups.
This animal he called a jellyfish and called Peytoia.

Photograph of a fossil originally interpreted as a sea cucumber
DESCRIPTION: Photograph of a fossil originally interpreted as a sea cucumber

This creature he called a sea cucumber and called Laggania.

Photograph of a fossil originally interpreted as a fossil shrimp
DESCRIPTION: Photograph of a fossil originally interpreted as a fossil shrimp

And this, which had been described before and looks like the body of an arthropod, he called (it had been named before) Anomalocaris, meaning “the odd shrimp”. Well I think that you’ve guessed it already.

Fossils of a complete Anomalocaris
DESCRIPTION: Fossils of a complete Anomalocaris

It turns out that all three go together. They form a single creature which is one of the weirdest of all the odd animals of the Burgess.

It’s also the largest Cambrian organism. Some specimens are almost a metre in length.

The so-called jellyfish is the mouth of this creature, working on a circular, nutcracker principle rather than the jaw of vertebrates principle.

The Anomalocaris itself turns out to be one of a pair of feeding appendages, and the so-called sea cucumber is the body of the whole animal.