The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous for prolific agnostid and ''

Elrathia kingii ''Elrathia'' is a genus of trilobite belonging to Ptychopariacea known from the mid-Cambrian of Laurentia (North America). ''E. kingii'' is one of the most common trilobite fossils in the USA locally found in extremely high concentrations within ...

'' trilobite remains (even though many areas are barren of fossils) and represents a Konzentrat-Lagerstätte. Varied soft bodied organisms are locally preserved, a fauna (including ''

Naraoia ''Naraoia'' is a genus of small to average size (about 2-4½ cm long) marine arthropods within the family Naraoiidae, that lived from the early Cambrian to the late Silurian period. The species are characterized by a large alimentary system and s ...

'', ''

Wiwaxia ''Wiwaxia'' is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. ''Wiwaxia'' fossils – mainly isolated scales, but sometimes complete, articulated fossils – are known from ear ...

'' and ''

Hallucigenia ''Hallucigenia'' is a genus of Cambrian animal resembling worms, known from articulated fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual ...

'') and preservation style (

carbonaceous film A carbonaceous film or carbon film is an organism outline of a fossil. It is a type of fossil found in any rock when organic material is compressed, leaving only a carbon residue or film. When an organism is buried under many layers of sedimen ...

) normally associated with the more famous

Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest foss ...

. As such, the Wheeler Shale also represents a Konservat-Lagerstätten. Together with the

Marjum Formation The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale The Burgess S ...

and lower Weeks Formation, the Wheeler Shale forms of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America. At the type locality of Wheeler Amphitheater,

House Range The House Range is a north-south trending mountain range in Millard County, of west-central Utah. The House Range was named in 1859 by James H. Simpson. It was named by Simpson because "...of its well-defined stratification and the resemblance ...

, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and thin, flaggy limestone. The Wheeler Formation (although the Marjum & Weeks Formations are missing) extends into the

Drum Mountains The Drum Mountains or Detroit Mountains are a desert range in Juab and Millard counties of western Utah. They lie within the Basin and Range Province, which is a series of generally north-south trending mountain ranges and valleys (or basins) ex ...

, northwest of the House Range where similar fossils and preservation are found.

Taphonomy and sedimentology

Detailed work recognises a number of ~10 m thick lagerstätten sequences in the formation, each of which formed at a sea-level high stand in deep water. The lagerstätte were deposited by turbidities and mudslides onto an oxygenated sea floor. The productive layers comprise mud and clay particles, with a tiny fraction of wind-blown quartz.

Stratigraphy

The Wheeler Shale spans the ''

Ptychagnostus atavus ''Ptychagnostus atavus'' is a species of agnostid trilobite. It was originally described by Swedish paleontologist Sven Axel Tullberg as ''Agnostus atavus'' in 1880. It is used in biostratigraphy as an index fossil. Its first appearance at the ...

'' and uppermost-Middle Cambrian '' Bolaspidella''

trilobite zone Trilobites are used as index fossils to subdivide the Cambrian period. Assemblages of trilobites define trilobite zones. The ''Olenellus''-zone has traditionally marked the top of the Lower Cambrian, and is followed by the '' Eokochaspis'' zone. ...

s (See

) for full stratigraphy).

Fauna

Incomplete list of the fauna of the Wheeler Shale: (Note: the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.)

Protista A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the excl ...

*''

Marpolia ''Marpolia'' has been interpreted as a cyanobacterium, but also resembles the modern cladophoran green algae. It is known from the Middle Cambrian Burgess shale and Early Cambrian deposits from the Czech Republic. It comprises a dense mass of e ...

spissa'' -

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

*'' Morania fragmenta'' - cyanobacteria

Arthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

*''

Branchiocaris ''Branchiocaris'' is an extinct genus of Cambrian bivalved arthropod. The type and best known species, ''Branchiocaris pretiosa,'' was described from the Burgess Shale of British Columbia, Canada, in 1929, originally placed in '' Protocaris'', a ...

pretiosa'' - hymenocarine *''Branchiocaris sp''. *'' Cambropodus gracilis'' -

uniramia Uniramia (''uni'' – one, ''ramus'' – branch, i.e. single-branches) is a group within the arthropods. In the past this group included the Onychophora, which are now considered a separate category. The group is currently used in a narrower sen ...

n *''

Canadaspis ''Canadaspis'' ("Shield of Canada") is an extinct genus of bivalved Cambrian arthropod, known from North America and China. They are thought to have been benthic feeders that moved mainly by walking and possibly used its biramous appendages to ...

perfecta'' - hymenocarine *'' Dicerocaris opisthoeces'' *''

Emeraldella ''Emeraldella'' is a genus of arthropod known from the Middle Cambrian of North America. The type species ''E. brocki'' was described in 1912 from the Burgess Shale. 21 specimens of ''Emeraldella'' are known from the Greater Phyllopod bed, where ...

brocki'' - vicissicaudatan *''

Isoxys ''Isoxys'' (meaning "equal surfaces") is a genus of extinct bivalved Cambrian arthropod; the various species of which are thought to have been freely swimming predators. It had a pair of large spherical eyes (which are the most commonly preserve ...

'' *''

Perspicaris ''Perspicaris'' (from the Latin ''perspicax'', meaning “sharp-sighted,” and ''caris'', “crab/shrimp”) an extinct genus of bivalved arthropod from the Cambrian period. Fossils have been found in North America, primarily the Burgess Shale ...

dilatus'' hymenocarine *'' Pseudoarctolepis sharpi'' - possible hymenocarine *''

Tuzoia ''Tuzoia'' (from Mount Tuzo, a mountain in the Canadian Rockies) is an extinct genus of large bivalved arthropod known from Early to Middle Cambrian marine environments from what is now North America, Australia, China, Europe and Siberia. The larg ...

''? ''peterseni'' hymenocarine *''

Waptia ''Waptia fieldensis'' is an extinct species of arthropod from the Middle Cambrian Burgess Shale ''Lagerstätte'' of Canada. It grew to a length of , and had a large bivalved carapace and a segmented body terminating into a pair of tail flaps. I ...

'' ''fieldensis'' hymenocarine *''

Alalcomenaeus ''Alalcomenaeus'' is one of the most widespread and longest-surviving arthropod genera of the Early and Middle Cambrian. Known from over 300 specimens in the Burgess Shale and the Chengjiang biota. it is a member of the group Megacheira. Morph ...

cambricus'' - megacheiran; or alalcomenaeid *'' Dicranocaris guntherorum'' - megacheiran; or alalcomenaeid *unnamed 'Molli Sonia symmetrica' *''

Leanchoilia ''Leanchoilia'' is an megacheiran arthropod known from Cambrian deposits of the Burgess Shale in Canada and the Chengjiang biota of China. It was about long and had long, whip-like feelers mounted on frontal arm-like appendages. Its internal o ...

'' superlata - megacheiran *''

Sidneyia ''Sidneyia'' is an extinct arthropod known from fossils found from the Early Cambrian-age Maotianshan Shales to the Mid Cambrian Burgess Shale formation of British Columbia. 144 specimens of ''Sidneyia'' are known from the Greater Phyllopod be ...

inexpectans'' - vicissicaudatan

Dinocaridida DinocarididaGreek, "Terrible crabs" – sometimes informally spelt Dinocarida, but the second 'id' is linguistically correct – see is a proposed fossil taxon of basal arthropods that flourished in the Cambrian period with occasional Ordovici ...

*''

Amplectobelua ''Amplectobelua'' (meaning "embracing beast") is an extinct genus of late Early Cambrian amplectobeluid radiodont, a group of stem arthropods that mostly lived as free-swimming predators during the first half of the Paleozoic Era. Anatomy ...

'' cf. ''A. stephenensis'' –

radiodont Radiodonta is an extinct Order (biology), order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the ...

Anomalocarididae Anomalocarididae (occasionally mis-spelt Anomalocaridae) is an extinct family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpo ...

gen. et sp. nov. - radiodont *'' Buccaspinea cooperi''? - radiodont *'' Caryosyntrips durus'' - radiodont *''Caryosyntrips serratus'' - radiodont *''

Peytoia nathorsti ''Peytoia'' is a genus of hurdiid radiodont that lived in the Cambrian period, containing two species, ''Peytoia nathorsti'' from the Miaolingian of Canada and ''Peytoia infercambriensis'' from Poland, dating to Cambrian Stage 3. Its two front ...

'' - radiodont *'' Pahvantia hastata'' - radiodont *''

Stanleycaris ''Stanleycaris'' is an extinct, monotypic genus of hurdiid radiodont from the middle Cambrian (Miaolingian). The type species is ''Stanleycaris hirpex''. ''Stanleycaris'' was described from the Stephen Formation near the Stanley Glacier and Bu ...

'' sp. - radiodont *''

Utaurora ''Utaurora'' is an extinct genus of opabiniid, which were bizarre stem-arthropods closely related to true arthropods and radiodonts; the type species is ''U. comosa''. The animal's fossils come from the Cambrian of Utah. This genus is so far ...

comosa -''

opabiniid Opabiniidae is an extinct family of bizarre marine stem- arthropods. Its type and best-known genus is ''Opabinia''. It also contains ''Utaurora''. Opabiniids closely resemble radiodonts, but their frontal appendages were basally fused into a pr ...

Trilobita Trilobites (; meaning "three lobes") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil reco ...

*''

compacta'' - naraoiid nectaspid *'' Hypagnostus parvifrons'' -

agnostid Agnostidae is a family of Agnostida trilobites. Like all Agnostina, they were eyeless and bore only two thoracic segments. They ranged in benthic waters across the globe from 508 to 461 million years ago, containing the following genera, among o ...

*'' Peronopsis amplaxis'' - peronopsid agnostid *''Peronopsis bidens'' *''Peronopsis fallax'' *''Peronopsis gaspensis'' *''Peronopsis intermedius'' *''Peronopsis interstrictus'' *''Peronopsis montis'' *''Peronopsis segmentis'' *''

'' (= ''Acidusus atavus'') - ptychagnostid agnostid *''

Ptychagnostus ''Ptychagnostus'' is a member of the agnostida that lived during the Cambrian period. Ptychagnostidae generally do not exceed one centimetre in length. Their remains are rarely found in empty tubes of the polychaete worm '' Selkirkia''. The gen ...

germanus'' *''Ptychagnostus gibbus'' *P''tychagnostus intermedius'' *''Ptychagnostus michaeli'' *''Ptychagnostus occultatus'' *''Ptychagnostus seminula'' *'' Glyphaspis concavus'' - asaphid *'' Bathyuriscus fimbriatus'' - dolichometopid corynexochid *''Bathyuriscus sp.'' *''

Kootenia ''Kootenia'' is a genus of trilobites of the family Dorypygidae. 118 specimens of ''Kootenia'' are known from the Greater Phyllopod bed, where they comprise 0.22% of the community. Its major characteristics are that of the closely related ''Olen ...

sp.'' - dorypygid corynexochid, perhaps a synonym of ''Olenoides'' *'' Olenoides expansus'' - dorypygid corynexochid *''Olenoides nevadensis'' *''Olenoides serratus'' *'' Tonkinella breviceps'' *''

Zacanthoides ''Zacanthoides'' is an extinct Cambrian genus of corynexochida, corynexochid trilobite. It was a nektobenthic predatory carnivore. Its remains have been found in Canada (British Columbia, especially in the Burgess Shale, and Newfoundland and Labr ...

divergens'' - zacanthoidid corynexochid *''Zacanthoides sp.'' *'' Altiocculus harrisi'' - ptychopariid (specific name may be confused with ''Alokistocare'') *'' Alokistocare harrisi'' - alokistocarid ptychopariid *'' Asaphiscus wheeleri'' - ptychopariid; second-most common species in the formation *'' Bathyocos housensis'' - ptychopariid *'' Bolaspidella drumensis'' *''Bolaspidella housensis'' *''Bolaspidella sp.'' *''Bolaspidella wellsvillensis'' *'' Brachyaspidion microps'' *''Brachyaspidion sulcatum'' *''

Cedaria ''Cedaria'' is a small, rather flat trilobite with an oval outline, a headshield and tailshield of approximately the same size, 7 articulating segments in the middle part of the body and spines at the back edges of the headshield that reach halfl ...

minor'' - known from the Warrior Formation *''

Elrathia ''Elrathia'' is a genus of trilobite belonging to Ptychopariacea known from the mid- Cambrian of Laurentia (North America). ''E. kingii'' is one of the most common trilobite fossils in the USA locally found in extremely high concentrations wit ...

kingii'' - alokistocarid ptychopariid *''Elrathia sp.'' *''

Elrathina Ptychoparioidea is a superfamily of the Ptychopariida order of trilobites.Pour M. G., Popov L. E. (2009) Silicified Middle Cambrian trilobites from Kyrgyzstan, Palaeontology, 1039-1056 Taxonomy *Family Acrocephalitidae *Family Alokistocaridae ...

wheeleri'' = ''Ptychoparella wheeleri''? - ptychopariid *'' Jenkinsonia varga'' *'' Modocia brevispina'' *''Modocia laevinucha'' *''Modocia typicalis'' *'' Ptychoparella sp.'' - ptychopariid *''Ptychoparella wheeleri'' *'' Spencella sp.'' - ptychopariid

Brachiopoda

*'' Acrothele subsidua''

Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...

*'' Hertzina sp.'' -

conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...

Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...

*'' Cambromedusa sp.'' -

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

*'' Pelagiella sp.'' - pelagiellid helcionelloid

Echinodermata An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

*'' Castericystis sprinklei'' -

carpoid Homalozoa is an obsolete extinct subphylum of Paleozoic era echinoderms, prehistoric marine invertebrates. They are also referred to as carpoids. Description The Homalozoa lacked the typical pentamer body form of other echinoderms, but all were ...

*''Castericystis sp.'' *''

Cothurnocystis ''Cothurnocystis'' is a genus of small enigmatic echinoderms that lived during the Ordovician. Individual animals had a flat boot-shaped body and a thin rod-shaped appendage that may be a stem, or analogous to a foot or a tail. Fossils of ''Cothu ...

sp.'' - stylophoran *'' Ctenocystis sp.'' - ctenocystoid *''

Gogia ''Gogia'' is a genus of primitive eocrinoid blastozoan from the early to middle Cambrian. ''G. ojenai'' dates to the late Early Cambrian; other species come from various Middle Cambrian strata throughout North America, but the genus has yet to ...

spiralis'' -

eocrinoid The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian. ...

*Eocrinoid holdfasts believed to belong to ''Gogia spiralis''; may belong to other species

Porifera

*''

Choia ''Choia'' is a genus of extinct demosponge ranging from the Cambrian until the Lower Ordovician periods. Fossils of ''Choia'' have been found in the Burgess Shale in British Columbia; the Maotianshan shales of China; the Wheeler Shale in Uta ...

carteri'' - choiid monaxonid

demosponge Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a har ...

*''Choia utahensis'' *'' Crumillospongia sp.'' - hazeliid monaxonid demosponge *'' Diagonella sp.''

Priapulida Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...

*''

Ottoia ''Ottoia'' is a stem-group archaeopriapulid worm known from Cambrian fossils. Although priapulid-like worms from various Cambrian deposits are often referred to ''Ottoia'' on spurious grounds, the only clear ''Ottoia'' macrofossils come from th ...

prolifica'' - a stem group and it was an archaeopriapulid *''

Selkirkia ''Selkirkia'' is a genus of predatory, tubicolous priapulid worms known from the Middle Cambrian Burgess Shale, Ogygopsis Shale and Puncoviscana Formation. 142 specimens of ''Selkirkia'' are known from the Greater Phyllopod bed, where they compr ...

sp.'' - archaeopriapulid *"Selkirkia willoughbyi" (Note: ''S. columbia'' is the only recognized species)

Unclassified

*''

sparsa'' - ?xenusiid

lobopod The lobopodians, members of the informal group Lobopodia (from the Greek, meaning "blunt feet"), or the formally erected phylum Lobopoda Cavalier-Smith (1998), are panarthropods with stubby legs called lobopods, a term which may also be used as ...

*'' Utahnax vannieri'' - stem-arthropod lobopod, also possible that is from

*''

Allonnia ''Allonnia'' is a genus of coeloscleritophoran known as complete scleritomes from the Middle Cambrian Burgess Shale. It is also a constituent of the small shelly fauna The small shelly fauna, small shelly fossils (SSF), or early skeletal foss ...

'' cf. ''tintinopsis'' - a

chancelloriid The Chancelloriids are an extinct family of superficially sponge-like animals common in sediments from the Early Cambrian to the early Late Cambrian. Many of these fossils consists only of spines and other fragments, and it is not certain that t ...

*''

Chancelloria ''Chancelloria'' is a genus of early animals known from the Middle Cambrian Burgess Shale, the Comley limestone, the Wheeler Shale, the Bright Angel Shale and elsewhere. It is named after Chancellor Peak. It was first described in 1920 by Char ...

pentacta'' -

coeloscleritophoran The Coelosclerithophorans are a polyphyletic group of organisms bearing hollow sclerites made of aragonite, and with a supposedly distinctive microstructure. Their skeletons may be homologous to those of the molluscs, and ''Halkieria'' looks very ...

, perhaps a

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

? *'' Eldonia sp.'' - eldoniid paropsonemid cambroernid *'' Skeemella clavula'' - Possible

vetulicolia VetulicoliaThe taxon name, Vetulocolia, is derived from the type genus, ''Vetulicola'', which is a compound Latin word composed of ''vetuli'' "old" and ''cola'' "inhabitant". is a taxon (either phylum or subphylum in rank) encompassing several ex ...

n *'' Hylolithellus sp.'' -

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

? *''

corrugata'' - halwaxiid?

lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

n *'' Yuknessia simplex'' - pterobranch *''

Margaretia ''Margaretia'' is a frondose organism known from the middle Cambrian Burgess shale and the Kinzers Formation of Pennsylvania. Its fronds reached about 10 cm in length and are peppered with a range of length-parallel oval holes. It was or ...

dorus'' - possibly organic tube associated with

hemichordate Hemichordata is a phylum which consists of triploblastic, enterocoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and includ ...

References

{{Cambrian preservational modes Geologic formations of Utah Cambrian System of North America Cambrian geology of Utah Paleontology in Utah