The Spence Shale Lagerstaumltte an important window intoCambrian biodiversity

Julien Kimmig1 Luke C Strotz12 Sara R Kimmig13 Sven O Egenhoff4 ampBruce S Lieberman121 Biodiversity Institute University of Kansas Lawrence KS 66045 USA2 Department of Ecology amp Evolutionary Biology University of Kansas Lawrence KS 66045 USA3 Pacific Northwest National Laboratory Richland WA 99354 USA4 Department of Geosciences Colorado State University Fort Collins CO 80523 USA

JK 0000-0001-8032-4272 SOE 0000-0002-3072-286X BSL 0000-0002-4353-7874Correspondence jkimmigkuedu

Abstract The Spence Shale Member of the Langston Formation is a Cambrian (Miaolingian Wuliuan) Lagerstaumltte innortheastern Utah and southeastern Idaho It is older than the morewell-knownWheeler andMarjum Lagerstaumltten fromwesternUtah and the Burgess Shale from Canada The Spence Shale shares several species with these younger deposits yet it alsocontains a remarkable number of unique species Because of its relatively broad geographical distribution and the variety ofpalaeoenvironments and taphonomy the fossil composition and likelihood of recovering weakly skeletonized (or soft-bodied)taxa varies across localities The Spence Shale is widely acknowledged not only for its soft-bodied taxa but also for itsabundant trilobites and hyoliths Recent discoveries from the Spence Shale include problematic taxa and provide insights aboutthe nature of palaeoenvironmental and taphonomic variation between different localities

Supplementary material A generic presencendashabsence matrix of the Spence Shale fauna and a list of the Spence Shalelocalities are available at httpsdoiorg106084m9figsharec4423145

Received 31 October 2018 revised 21 February 2019 accepted 28 February 2019

The Early Paleozoic has yielded a remarkable number of fossil-bearing sediments preserving weakly skeletonized (or soft-bodied)fossil taxa (Gaines 2014 Van Roy et al 2015Muscente et al 2017Pates amp Daley in press) The Great Basin of the western USApreserves a significant number of Cambrian Burgess Shale-typedeposits including the Pioche Formation of Nevada (Lieberman2003) the Wheeler Marjum andWeeks formations of western Utah(Robison 1991 Robison et al 2015 Foster ampGaines 2016 Lerosey-Aubril et al 2018) and the Spence Shale of northeastern Utah andsoutheastern Idaho (Robison 1991 Liddell et al 1997 Robisonet al 2015) These deposits contain an exceptional number of soft-bodied fossils preserved as 2D mineral films and thus greatlyextend our knowledge of Cambrian evolution and palaeoecology

The Spence Shale is one of five Cambrian Konservat-Lagerstaumltten that occurs in Utah the others comprise the (lsquodeeprsquo)Wheeler Marjum and Weeks formations in the House Range andthe (lsquoshallowrsquo) Wheeler Formation in the Drum Mountains(Robison 1991 Briggs et al 2008 Robison et al 2015 Foster ampGaines 2016 Lerosey-Aubril et al 2018) The Spence Shalepreserves a diverse fauna of soft-bodied and skeletonized taxa andeach of these are dominated by arthropods (Robison et al 2015) itis also the oldest of the Cambrian Lagerstaumltten of Utah dating backto the early Wuliuan Stage (Robison amp Babcock 2011) TheLagerstaumltten in the Wheeler Marjum and Weeks formations ofwestern Utah are younger (BolaspidellandashCedaria trilobite biozones)but have several taxa in common with the Spence Shale Member(Liddell et al 1997 Robison amp Babcock 2011 Robison et al 2015Lerosey-Aubril et al 2018 Pates et al 2018) Thus far the twoLagerstaumltten of the Wheeler Formation (House Range and DrumMountains) have been the most intensively studied Cambrian unitscontaining soft-bodied taxa in Utah (Gaines amp Droser 2005 Gaineset al 2005 Brett et al 2009 Halgedahl et al 2009 Kloss et al

2015 Foster amp Gaines 2016) thus the depositional environmentsichnology and taxonomy are known to an exceptional degree ofdetail The slightly younger Marjum Formation has also received asignificant amount of attention (Elrick amp Snider 2002 Brett et al2009 Robison et al 2015) The Weeks Formation Lagerstaumltte is theyoungest of the Burgess Shale-type deposits of Utah (Proagnostusbulbus biozone) and has received relatively little study (Robison ampBabcock 2011 Lerosey-Aubril et al 2012 2018 Robison et al2015) although it contains some soft-bodied animals (Lerosey-Aubril et al 2013 2014 2018 Lerosey-Aubril 2015 Ortega-Hernaacutendez et al 2015) The Spence Shale occupies an intermediateposition between these three formations Several comprehensivestudies of Spence palaeontology exist such that there is a goodknowledge of the biota contained within (for a recent review seeRobison et al 2015) However new taxonomic discoveriescontinue to be made from the Spence Shale (eg Kimmig et al2017) In a similar vein Spence sedimentology and geochemistryhave been studied (eg Liddell et al 1997 Garson et al 2012 Klosset al 2015) but recent fieldwork conducted by Kimmig and Strotzand associated taphonomic and sedimentological analyses (Kimmiget al 2018) have revealed new and distinctive patterns ofpalaeoenvironmental and taphonomic variation across the geo-graphical and temporal breadth of the Spence Shale

The Spence Shale occupies a distinctive position among theLagerstaumltten of Utah as it preserves a range of environments fromshallowwater carbonates to deep shelf dark shales Although this byitself is not unique the fact that soft-bodied organisms are found inthe mudstones of the Wellsville Mountains and the deeper watersediments of Idaho allows for a unique opportunity to understandthe taphonomic pathways of soft-bodied preservation in differentenvironments within one member In addition the presence ofseveral laminae and beds preserving soft-bodied fossils in different

copy 2019 The Author(s) This is an Open Access article distributed under the terms of the Creative Commons Attribution 40 License (httpcreativecommonsorglicensesby40) Published by The Geological Society of London Publishing disclaimer wwwgeolsocorgukpub_ethics

Review Focus Journal of the Geological Society

Published online March 29 2019 httpsdoiorg101144jgs2018-195 | Vol 176 | 2019 | pp 609ndash619

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carbonate cycles within each outcrop of the Wellsville Mountainsoffers the chance to study changes in taphonomic pathways anddiagenetic effects on soft-tissue preservation within one locality

Material and methods

Skeletonized fossils were photographed dry and all soft-bodiedfossils were photographed submerged in ethanol using a CanonEOS 5D or 7D Mark II digital SLR camera equipped with Canon50 mm macro lens or a Leica DMS 300 digital microscope Thecontrast colour and brightness of images were adjusted usingAdobe Photoshop All figured fossils are part of the University ofKansas Biodiversity Institute Division of InvertebratePaleontology collections (KUMIP)

Sedimentological analyses are based on macroscopic andmicroscopic observations Thirty ultrathin (lt20 microm) polished thinsections of the shale and limestone stratigraphic intervals were

analysed Samples for thin sections were taken at c 1 m intervalsalong the Spence Shale exposure at Miners Hollow (Fig 1) This isperhaps the best-known Spence Shale locality and has also yieldedthe most diverse soft-bodied biota

Data for the generic presencendashabsencematrix in themajor SpenceShale locations were collected from literature (Robison et al 2015and references therein ConwayMorris et al 2015a b Kimmig et al2017 Pates amp Daley 2017 Hammersburg et al 2018 Pates et al2018) and museum databases (KUMIP Yale University PeabodyMuseum (YPM) Harvard University Museum of ComparativeZoology (MZC) and United States National Museum of NaturalHistory (USNM)) and iDigBio (wwwidigbioorg)

Locality geological setting and depositional environment

The Spence Shale Member is the middle member of the LangstonFormation (Fig 1c sometimes referred to as the Twin Knobs

Fig 1 Locations and stratigraphy of the Spence Shale Lagerstaumltte (a) Map of the western USA showing the location of the Spence Shale (b) Geologicalmap (based on the USGS state maps for Google Earth Pro) of northern Utah and southern Idaho showing the principal localities within the Spence ShaleAC Antimony Canyon BF Blacksmith Fork CC Cataract Canyon CFC Calls Fort Canyon DC Donation Canyon EC Emigration Canyon HC HansenCanyon HCR High Creek MH Miners Hollow ON Oneida Narrows PP Promontory Point SG Spence Gulch TMC Two Mile Canyon (c) Simplifiedstratigraphy of the Langston Formation

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Formation or Lead Bell Shale) The Langston Formation is an earlymiddle Cambrian (c 5075ndash506 Ma Miaolingian Wuliuan) unit(Albertella to Glossopleura biozones) that crops out in northeasternUtah and southeastern Idaho (Fig 1 Walcott 1908 Maxey 1958Oriel amp Armstrong 1971 Liddell et al 1997 Robison amp Babcock2011) It conformably overlies the lower Cambrian GeertsenCanyon Quartzite of the Brigham Group and is divided into threemembers the Naomi Peak Limestone Spence Shale and HighCreek Limestone (Maxey 1958 Liddell et al 1997 Hintze ampKowallis 2009 Garson et al 2012) The type location of theLangston Formation is in Blacksmith Fork (Fig 1b) and theformation is named after the nearby Langston Creek (Walcott 1908)The type locality of the Spence Shale is at lsquoSpence Gulchrsquo insoutheastern Idaho (Fig 1b)

The Spence Shale preserves carbonate mudstones (thesepredominate) to carbonate-rich siliciclastic mudstones (Box 1Fig 2) and has been interpreted to have been deposited in the middlecarbonate to outer detrital belt of a now west-facing carbonateplatform (Palmer 1971 Robison 1991 Liddell et al 1997) TheSpence Shale shows excellent geographical and stratigraphicexposure over broad areas in northeastern Utah and southeasternIdaho (see supplementary material) It is assigned to the AlbertellandashGlossopleura trilobite biozones and is interpreted to represent

sedimentation on a shelf although no details are currently knownabout depositional depth relative to wave base (Liddell et al 1997)Exposures vary from c 9 m at Blacksmith Fork (Walcott 1908Deiss 1938) to c 120 m at Oneida Narrows (Liddell et al 1997)and the most important localities to date are Miners HollowAntimony Canyon and Cataract Canyon (all in the WellsvilleMountains) and High Creek Spence Gulch and Oneida Narrows inthe Bear River Range (Fig 1b) However other localities have alsoyielded a variety of skeletonized and soft-bodied fossils

The palaeontological significance of the Spence Shale has beenrecognized for over 100 years (Box 2 Walcott 1908 Robison 19651969 1991 Gunther amp Gunther 1981 Conway Morris amp Robison1982 1986 1988 Briggs et al 2008 Robison amp Babcock 2011Robison et al 2015) and important efforts have also focused oncharacterizing the depositional environments within this member(Liddell et al 1997 Garson et al 2012 Kloss et al 2015) TheSpence Shale contains up to eight parasequences or carbonatecycles (Maxey 1958 Liddell et al 1997 Garson et al 2012) TheWellsville Mountain localities are considered the most proximalSpence deposits and contain extensive soft-bodied fossils (Liddellet al 1997 Garson et al 2012) the depositional setting becomesmore distal towards the NE This is indicated by the reducedpresence of dolomites and limestones and the number of soft-

Box 1 Sedimentology of the Spence Shale in the Wellsville Mountains

The Spence Shale consists of carbonate mudstones to carbonate-rich siliciclastic mudstones that are sub-millimetre- to several centimetre-scale laminated and beddedand contain abundant millimetre- to decimetre-scale carbonate beds and laminae Wackestones occur as millimetre-thick lenses The mudstones are also irregular inthickness and in some places lenticular In several portions throughout the succession millimetre-thick accumulations of biogenic carbonate debris are intercalatedinto the succession that have sharp irregular bases in places and pinch out laterally Isolated biogenic carbonate debris is common throughout the succession and isgenerally oriented parallel to subparallel to bedding Organic matter in this unit consists of sub-millimetre wide flattened flakes in many places associated with pyritewhich is generally concentrated in distinct laminae Locally it forms lens-shaped slightly inclined accumulations directly adjacent to biogenic debris All siliciclasticmudstones contain abundant silt-size carbonate grains that are generally rounded to some degree as well as platy clay minerals In places macroscopically visibleburrows are common in these rocksThe carbonate beds are of irregular thickness laterally and can be nodular They consist of either carbonate mudstones with lenses of silty packstones composed of

peloids or up to decimetre-thick carbonate wacke- to packstones made up of biogenic debris and aggregate grains Grains in this facies are poorly sorted generallyrecrystallized and contain a micritic outer rim Burrows with varying orientations are common in these rocks Fractures showing a clear zigzag pattern occur in boththe carbonates and the siliciclastic mudstones but are more common in the mudstones and are filled with a clear carbonate cement that is structurelessThe abundance of carbonate mud and grains suggests that the Spence Shale was the distal equivalent of a carbonate system probably a rimmed carbonate platform

based on lagoonal components such as the aggregate grains and peloids The depositional environment shows a transition from carbonate-rich shales in proximalareas to siliciclastic shales distally High-energy events probably storms must have been abundant in all environments as reflected in sharp irregular bases hereinterpreted as scours at the base of carbonate and siliciclastic mudstone beds lens-shaped bedding indicating bed-load transport and carbonate debris forming lagsThe great quantity of burrows in the carbonates indicates abundant benthic life during deposition of this unit in carbonate facies the same appears partly true with thesiliciclastic mudstones The cement-filled fractures are here interpreted as recrystallized originally mud-filled clastic dykes probably reflecting synsedimentaryearthquakes in the Spence Shale

Fig 2 Sedimentology of the Spence Shale (a) Lag deposit near base of lsquocycle 3rsquo consisting of biogenic debris probably of echinoderm brachiopod andtrilobite remains It should be noted how bedding bends around the millimetre-size echinoderm bioclasts The matrix is carbonate-rich siliciclastic mudstonewith varying amounts of sub-millimetre carbonate debris (b) Carbonate-rich siliciclastic mudstone near top of lsquocycle 3rsquo with several millimetre-long blackorganic-rich flakes oriented parallel to bedding Abundant silt-size carbonate particles in the matrix should be noted Scale bar is 1 mm

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bodied fossils also declines in this direction (Liddell et al 1997Garson et al 2012) Recent investigations of the LangstonFormation type locality at Blacksmith Fork Utah (Bear RiverRange) suggest that it might represent an even more proximalenvironment than the Wellsville Mountains as it preserves largeamounts of dolomites indicating shallow water conditions (Maxey1958 J Kimmig pers obs) The Blacksmith Fork locality hasyielded few soft-bodied fossils to date but is valuable for inferringhow ecological communities varied along the Cambrian SpenceShale shelf from shallow to deep water Although fossils are inplaces well preserved in the Spence Shale burrows are alsoubiquitous both in proximal and distal shelf sediments Thepresence of trace fossils indicates that dynamic redox conditionsmay have prevailed during the deposition of the shale-bearing distalSpence environment (Garson et al 2012 Hammersburg et al2018) However the fine-scale distribution of burrows and fecalstrings can be deduced only via thin sections and although thesewere recently collected (Kimmig et al 2018) they have not yet beenstudied in sufficient quantity to ascertain the precise prevalence anddistribution of dynamic redox states (Egenhoff amp Fishman 2013)

Taphonomy

There have been numerous hypotheses offered to account for thetype of soft-bodied preservation seen in the Spence Shale Somehave suggested it is the result of an oxygen-depleted environment inconjunction with rapid burial (eg Gaines et al 2012 Garson et al2012) although oxygen depletion in and of itself cannot account forsoft-tissue preservation (Allison 1988) Intriguingly the SpenceShale does not record evidence of constant anoxia (Garson et al2012 Kloss et al 2015 Hammersburg et al 2018) In fact in theSpence Shale soft-bodied fossils are also found in association withbioturbated sediments (Garson et al 2012 Kimmig amp Strotz 2017)and geochemical analysis of some intervals indicates oxygenatedbottom waters (Kloss et al 2015) One of the notable aspects of theSpence Shale is that there appears to be significant variation in thedegree of soft-bodied preservation and also the range of taxapreserved within any given exposure and across localities(supplementary material Liddell et al 1997 Garson et al 2012Robison et al 2015) For instance Broce amp Schiffbauer (2017)analysed 10 vermiform fossils from the Spence Shale (eight from

Box 2 Collections history of the Spence Shale

The Spence Shale was first described by CharlesWalcott (1908) from Spence Gulch in Idaho (Fig 1b) Since then palaeontologists have unearthed a treasure trove offossils from the unit especially in theWellsville Mountains north of Brigham City Utah Its potential scientific valuewas already recognized byWalcott (1908 p 8)who called it lsquoan extremely abundant and varied lower Middle Cambrian faunarsquo The scientific merit of the Spence Shale began to come to fruition through the workof Deiss (1938) Resser (1939) and Maxey (1958) and especially in publications by Dick Robison and colleagues that highlighted the soft-bodied biota (Robison1969 1991 Robison amp Richards 1981 Briggs amp Robison 1984 ConwayMorris amp Robison 1986 1988 Babcock amp Robison 1988) One of the chief reasons for theSpence Shale becoming a deposit so well known for soft-bodied preservation was the extensive and diligent efforts by several private collectors which tremendouslyaided and facilitated the work by Robison and colleagues as well as of subsequent researchers (eg Briggs et al 2005 2008 Robison amp Babcock 2011 ConwayMorris et al 2015a b Kimmig et al 2017 Pates et al 2018)In particular the contributions of the famous Gunther family (Lloyd Val and Glade Fig 3a and b) of BrighamCity UT winners of the prestigious Strimple Award

from the Paleontological Society (USA) stand out including their scientific publications (eg Gunther ampGunther 1981) They started collecting in the Spence Shaleas well as in theWheeler Marjum andWeeks formations around 1965 and their efforts have contributed over 75 of all known Spence Shale specimens to museumcollections a remarkable legacy The Gunther family was later joined by Phil Reese and Paul Jamison (Fig 3c) and they extended the tradition of giving scientificallyimportant specimens to museums Indeed it is no exaggeration to state that these collectors are the major reason the diversity of the Spence Shale is so wellunderstood without their contributions the many taxonomic studies of Spence Shale fossils would not have been possible In many respects this legacy continues asthese enthusiastic private collectors are still one of the driving forces behind the exploration of the Cambrian deposits of Utah The majority of soft-bodied fossilswould probably never have been found were it not for the passion of these people Given that new species are still being described from this unit and that there areseveral specimens in museum collections that are currently unidentifiable palaeontologists can only hope that such collection efforts continue further contributing toour knowledge of Cambrian biodiversity

Fig 3 Important private collectors (a) Lloyd Gunther of Brigham City UT (b) Val (right) and Glade (left) Gunther of Brigham City UT (c) Paul Jamisonof Logan UT

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Miners Hollow one from Antimony Canyon and one from anindeterminate locality in the Wellsville Mountains) and found avariety of preservational modes associated with these fossils Themost common form of preservation in these fossils was pyritizationbut several fossils showed kerogenization and aluminosilicificationfurther phosphatization as well as barite monazite and calciteassociations were found (Broce amp Schiffbauer 2017)

The different preservational styles in the Spence Shale haveunfortunately not yet been fully explored at the millimetre-scale butare probably due to changes in ocean water chemistry andsedimentology This will be important to more precisely ascertaindepositional environments as has been done for other well-knownsoft-bodied deposits (eg Gabbott et al 2008) The role thatdiagenesis plays in mediating soft-bodied preservation (egButterfield et al 2007) has also yet to be unravelled Thusadditional work is required to tease apart the various taphonomicpathways involved in soft-bodied preservation in the Spence ShaleThis would have the added benefit of helping elucidate the factorsgenerally responsible for soft-bodied preservation in shales Furtherstudies currently under way (eg Kimmig et al 2018) will be avaluable step forward

Overview of the Spence Shale biota

To date 87 species in 71 genera that belong to at least 10 phyla havebeen described from the Spence Shale (Figs 4andashl and 5andashlsupplementary material) Two-thirds of the species in the SpenceShale are well skeletonized and such taxa are not only more diversebut also significantly more abundant than the co-occurring soft-bodied taxa The greatest diversity of soft-bodied taxa is found atMiners Hollow followed by Antimony Canyon 20 and 14 soft-bodied species respectively More information on the fauna algaecyanobacteria and trace fossils is provided in the subsequentsections and the soft-bodied arthropods are discussed in Box 3

Arthropods

Trilobites and agnostoids

Trilobites are the most diverse group in the Spence Shale and arerepresented by 41 species in 25 genera Agnostoid trilobites can beabundant locally but are generally less common and only twospecies are known Peronopsis bonnerensis and P brighamensisSuch a low diversity of agnostoids is among Cambrian soft-bodieddeposits from Utah unique to the Spence Shale and might suggest amore restricted andor proximal environment compared with theother Utah Lagerstaumltten Trilobite diversity is the highest at SpenceGulch (16 genera) in Idaho and the Wellsville Mountain localitiesin Utah (17 genera) Because of the lack of available collectionsfrom High Creek and Blacksmith Fork it is unclear how manygenera are present in these deposits

Ptychopariid and corynexochid trilobites are the most commontypes of trilobites in the Spence Shale and can be found throughoutmost of the exposures Recent comprehensive discussions on thesehave been provided by Robison amp Babcock (2011) and Robisonet al (2015) Distinctive biostratigraphic patterns among Spencetrilobites were described by Campbell (1974) who argued that theremay be some turnovers preserved in the trilobite fauna at AntimonyCanyon Further study is needed to confirm whether these turnoversappear at other Spence Shale locations

In the Wellsville Mountains the trilobites usually appear asisolated specimens with only one to a few often completeexoskeletons preserved per slab Preserved soft parts have notbeen described to this point but a few unpublished specimens fromMiners Hollow actually display gut structures In Spence Gulchisolated trilobites are present but lsquotrilobite-hashrsquo containing dozens

to hundreds of broken specimens is dominant Some of the hash isdeposited in ribbon-like and circular forms resembling coprolites

Soft-bodied arthropods

Soft-bodied arthropods are the most diverse clade other thantrilobites from the Spence Shale with currently 14 speciesidentified Fossils of this type are mostly limited to the WellsvilleMountains (Box 3 Fig 4andashl)

Lobopodians

Acinocricus stichus Conway Morris amp Robison 1988 is the onlylobopodian species known from the Spence Shale (Robison et al2015) Specimens can be easily identified by their prominent spines(Fig 5g) and are fairly common with at least 50 specimens knownfrom Miners Hollow Antimony Canyon and Donation Canyon inthe Wellsville Mountains Complete (or largely complete) speci-mens are rare however and most of the time only isolated segmentsare preserved Previous studies have concluded that Acinocricus is aluolishaniid a group of ecologically specialized lobopodians with aworldwide distribution (Spence Shale Burgess Shale ChengjiangEmu Bay and Xiaoshiba) (Yang et al 2015)

Scalidophorans

Vermiform fossils are abundant in the Spence Shale but theyusually do not preserve diagnostic characteristics However the fewspecimens that are well enough preserved retain extensive detail(Fig 5c and d) For instance a palaeoscolecid is known fromMinersHollowWronascolex ratcliffei (Robison 1969 Conway Morris ampRobison 1986 Garciacutea-Bellido et al 2013) and is represented by twospecimens the holotype (KUMIP 204390 UU1020) and a recentlycollected specimen with an everted proboscis (KUMIP 490902Fig 5c) Ottoia prolifica and two species of Selkirkia S spenceiand S cf columbia represent the only other scalidophorans in theSpence Shale (Robison et al 2015) Ottoia has been reported onlyfrom Miners Hollow and Antimony Canyon (supplementarymaterial) whereas Selkirkia has also been found in the LangstonFormation type section at Blacksmith Fork (Resser 1939) Thespecimen from Blacksmith Fork comprises solely the external tube

Lophophorates

Brachiopods and hyoliths are some of the most common fossils in theSpence Shale and can be preserved in concentrations containingdozens of specimens Despite the high abundance the brachiopodshave received little attention and the six species known from theSpence Shale (Resser 1939 Robison et al 2015 supplementarymaterial) probably represent only a fraction of overall diversity A fewof the specimens fromHighCreek preserve chaetae (Fig 5h) Some ofthe hyoliths in the Wellsville Mountains referable to Haplophrentisreesei preserve soft tissues and these have been interpreted asevidence of a lophophore and pharynx (Moysiuk et al 2017) Theother two genera of hyoliths Hyolithellus and Hyolithes are lesscommon no specimens with soft-bodied preservation are known

Molluscs

Molluscs are extremely rare in the Spence Shale and are found onlyin the Wellsville Mountains Only two species have been describedLatouchella arguata and Scenella radians (Babcock amp Robison1988) and little material has been added since the initialdescriptions The soft-bodied Wiwaxia herka (Fig 5b) is the mostcommon mollusc in the Wellsville Mountains In addition anundescribed halkieriid has recently been discovered in MinersHollow by Paul Jamison

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Sponges

Sponges are a rare element of the Spence Shale fauna and only threespecies have been described two of which Vauxia gracilenta andVauxia magna (Fig 5a) are known from only four specimens totalfrom the Wellsville Mountains (Rigby 1980 Robison et al 2015)This is different from other Utah Lagerstaumltten where sponges aretypically the most diverse phylum after arthropods There are othersponges from the Bear River Range Protospongia hicksi has beenreported from the Oneida Narrows locality (Fig 1b) wherehundreds of specimens have been recovered from a 2 m interval(Church et al 1999)

Echinoderms

Echinoderms are fairly common in the Spence Shale and can befound at most localities They are represented by at least six speciesthe most common being Ctenocystis utahensis which often appearsin mass assemblages and three species of Gogia G granulosaG guntheri and G palmeri Robison et al (2015) also mentionednew Gogia and totiglobid species but they have not yet beendescribed Lyracystis reesei and Ponticulocarpus robisoni arerelatively rare and have thus far been reported from only theWellsville Mountains (Sumrall amp Sprinkle 1999 Sprinkle ampCollins 2006)

Fig 4 Selected soft-bodied arthropods from the Spence Shale (a) KUMIP 204511 holotype of Meristosoma paradoxum from Miners Hollow collected bythe Gunther family (b) KUMIP 314041 Mollisonia symmetrica from Miners Hollow collected by the Gunther family (c) KUMIP 314038 Waptia cf Wfieldensis from Cataract Canyon collected by Val and Glade Gunther (d) KUMIP 312404 Isoxys sp from Miners Hollow collected by Arvid Aase(e) KUMIP 314036 Tuzoia sp with burrows under the carapace from Miners Hollow collected by Phil Reese (f ) KUMIP 204783 Leanchoilia superlatafrom Miners Hollow collected by Val and Glade Gunther (g) KUMIP 314027 hurdiid H-element from Miners Hollow collected by the Gunther family(h) KUMIP 491056 Hurdia sp appendage from Miners Hollow collected by Paul Jamison (i) KUMIP 204777 arthropod appendage from AntimonyCanyon collected by Val Gunther ( j) KUMIP 491904 Dioxycaris argenta from Miners Hollow collected by the Gunther family (k) KUMIP 357406holotype of Yohoia utahana from Miners Hollow collected by Paul Jamison (l) KUMIP 204784 holotype of Utahcaris orion from Antimony Canyoncollected by Ben Datillo Scale bars represent 10 mm for (a) (e) and (l) and 5 mm for (b) (c) (d) and (f )ndash(k)

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Fig 5 Selected fossils from the Spence Shale (a) KUMIP 491902 and KUMIP 491903 Vauxia magna from Miners Hollow collected by RhiannonLaVine (b) KUMIP 287449 holotype of Wiwaxia herka from Miners Hollow collected by Phil Reese and the Gunther family (c) KUMIP 490902Wronascolex ratcliffei from Miners Hollow collected by Riley Smith (d) KUMIP 314115 Selkirkia spencei from the Wellsville Mountains collected bythe Gunther family (e) KUMIP 204370 Eldonia ludwigi from Antimony Canyon collected by Lloyd and Val Gunther (f ) KUMIP 339907 Sphenoeciumwheelerensis from Miners Hollow collected by the Gunther family (g) KUMIP 491080 Acinocricus stichus from Miners Hollow collected by PaulJamison (h) KUMIP 490932 Micromitra sp from High Creek with chaetae preserved collected by Paul Jamison (i) KUMIP 491805 lsquoenrolledrsquoAmecephalus laticaudum from Miners Hollow collected by Paul Jamison ( j) KUMIP 491808 Zacanthoides liddelli from High Creek collected by PaulJamison (k) KUMIP 491853 Oryctocephalus walcotti from Oneida Narrows collected by the Gunther family (l) KUMIP 135150 holotype ofSiphusauctum lloydguntheri from Antimony Canyon collected by Lloyd Gunther Scale bars represent 5 mm

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Hemichordates

Hemichordates are represented by two species the proposedenteropneust tube Margaretia dorus (see Nanglu et al 2016) andthe pterobranch Sphenoecium wheelerensis (Maletz amp Steiner2015) Both species are common in the Wellsville Mountains buthave not yet been found in Idaho or in the more eastern exposures inUtah (supplementary material)

Problematica

Three species of problematic taxa have been described from theSpence Shale Banffia episoma Eldonia ludwigi and Siphusauctumlloydguntheri (Fig 5e and i) (Conway Morris amp Robison 1988Conway Morris et al 2015a b Kimmig et al 2017) two of thethree were species originally described from the Burgess ShaleSiphusauctum lloydguntheri (Fig 5l) is known from a singlespecimen from near the top of Antimony Canyon (Kimmig et al2017) it is a congener of the species described from the BurgessShale The other two species are all known frommultiple specimensand Eldonia can be found in several localities within the SpenceShale (supplementary material)

Algae and cyanobacteria

Marpolia spissa is the only alga currently recognized from theSpence Shale it has been reported from Antimony Canyon(Conway Morris amp Robison 1988) Its precise affinities amongalgae have been debated and it has even been interpreted as aprokaryote (see LoDuca et al 2017) The possible cyanobacteriumMorania fragmenta has been reported from the WellsvilleMountains although its biological affinities are also questionable(Handle amp Powell 2012) and it might actually represent fecal pellets(Robison et al 2015)

Trace fossils

Trace fossils are common in the Wellsville Mountains and morethan 35 ichnospecies have been described These range fromburrows to moving and resting traces to a variety of coprolites(Fig 4e Kimmig amp Strotz 2017 Hammersburg et al 2018)Ichnofossils have the highest diversity in the Wellsville Mountainsbut Planolites and Diplichnites can be found in Oneida Narrowsand Diplichnites Rusophycus and Treptichnus have been reportedfrom High Creek (supplementary material Hammersburg et al2018)

Palaeoecology

The Spence biota is similar to other Cambrian Burgess Shale-typebiotas in that the fauna is dominated by arthropods (eg Caron ampJackson 2008 Kimmig amp Pratt 2015 Foster amp Gaines 2016Paterson et al 2016 Hou et al 2017 Lerosey-Aubril et al 2018)When considering well-skeletonized taxa trilobites outnumber allthe other groups in terms of specimens in museums by a factor of c91 echinoderms and hyoliths are the next most abundant groups inSpence Shale museum collections The diverse echinoderm fauna isunique relative to other Cambrian Lagerstaumltten of Laurentia asusually sponges are the second most dominant phylum (eg Caronamp Jackson 2008 Robison et al 2015) The Spence Shale mayrepresent a distinct environment perhaps more oxygenated basedon the presence of these as well as the abundant trace fossilsTrilobites also seem to dominate in field samples (J Kimmig persobs) Notably there are some well-skeletonized groups that arequite rare in museum collections from the Spence Shale such asmolluscs and this rarity probably represents true rarity in the fieldbut the relative paucity of brachiopods in museum collections seemsto be a matter of sampling (J Kimmig pers obs) This is somethingthat has to be considered for future palaeoecological analyses (egLieberman amp Kimmig 2018)

Box 3 Soft-bodied arthropods of the Spence Shale

Arthropods are the dominant component throughout the Spence Shale and are currently represented by 57 species in 40 genera (ConwayMorris et al 2015a Robisonet al 2015 Pates amp Daley 2017 Pates et al 2018) The majority of the species are trilobites and agnostoids comprising 43 species The most abundant trilobites inthe Wellsville Mountains are Amecephalus Athabaskia and Ogygopsis and other trilobite genera co-occur At Oneida Narrows Oryctocephalus Oryctocara andPentagnostus represent over 90 of the diversity and several dozen specimens can appear on one slab possibly indicating a restricted environment The 14 species ofsoft-bodied arthropods with the exception of some carapaces are restricted to localities in theWellsville Mountains north of Brigham City Utah in particular MinersHollow and Antimony Canyon (supplementary material) Many of the Spence Shale taxa are otherwise known only from the Burgess Shale (egWaptia Yohoia) orare endemic to the Spence Shale like the probable stem-chelicerate Utahcaris orion (Conway Morris amp Robison 1988 Legg amp Pates 2017) Fully articulated well-preserved specimens are rare when compared with deposits such as the Burgess Shale but when they are present they can preserve fine details of the appendageslimbs and other parts of the body (Fig 4andashl) Four bivalved arthropods have been described from the Spence Shale Canadaspis cf C perfecta Dioxycaris argentaIsoxys sp and Tuzoia retifera They rarely have body parts associated and often are isolated carapaces which is indicative of decomposition before burial or possiblepredation (Kimmig amp Pratt 2016 2018 Kimmig amp Strotz 2017) Tuzoia represents the largest bivalved arthropod from the Spence Shale with some valves reaching12 cm long by 8 cm wide Radiodonts are also fairly common in the Spence Shale and at least three species are known an indeterminate Anomalocaris species(Briggs et al 2008) Caryosyntrips camurus (Pates amp Daley 2017) and at least one species of Hurdia H victoria (Pates et al 2018) It is likely that there are morespecies present as some specimens have not yet been assigned to species or genus (Fig 4g and h Pates et al 2018) Anomalocaris appears to have been the largestradiodont whereas most hurdiids were fairly small (Briggs et al 2008 Pates et al 2018) The radiodonts of the Spence Shale have a variety of interpreted feedinghabits including grasping graspingndashslicing and sediment sifting

Box 4 Outstanding questions

(1) What factors make the Wellsville Mountains localities more likely to preserve soft-bodied fossils than other Spence Shale localities

(2) What are the patterns of ecological association in the Spence Shale

(3) What are the stratigraphic relationships among the various Spence Shale localities

(4) How does the Spence Shale correlate with other deposits within and outside the Great Basin

616 J Kimmig et al

by guest on July 4 2020httpjgslyellcollectionorgDownloaded from

In terms of soft-bodied fossils the Spence Shale again is similarto other lower and middle Cambrian Lagerstaumltten (eg Caron ampJackson 2008 Kimmig amp Pratt 2015 Foster amp Gaines 2016Paterson et al 2016 Hou et al 2017 Lerosey-Aubril et al 2018) asit is dominated by arthropods (Box 3 supplementary material)which make up about half of the soft-bodied genera In terms ofabundance only vermiform fossils exceed arthropods Eldoniids arelocally abundant in the Spence Shale and can occur on slabs withdozens of specimens at Miners Hollow and Cataract Canyon Manysoft-bodied taxa comprise autochthonous benthic species such ashemichordates scalidophorans lobopodians Wiwaxia spongesrare stalked filter feeders some arthropods and various trace makerssupporting the notion of tolerably well-oxygenated bottom waters(Church et al 1999 Robison et al 2015 Kimmig amp Strotz 2017Kimmig et al 2017 Kimmig amp Pratt 2018 Pratt amp Kimmig 2019)There were however also many putatively nektonic (or evenpelagic) taxa such as Banffia radiodonts and Tuzoia (ConwayMorris et al 2015a b Robison et al 2015 Pates et al 2018) andMarpolia spissa is a possible denizen of the plankton (Kimmig et al2017)

Based on the generic presencendashabsence list of Lerosey-Aubrilet al (2018) and the list generated for this paper (supplementarymaterial) there are at least 26 genera found in the Spence Shale thathave not been reported from other Utah Lagerstaumltten Although partof this might be due to the older age of the deposit several of thetaxa have been reported from younger Burgess Shale suggestingthat at least part of it might be due to different environmentalconditions when compared with the other Cambrian UtahLagerstaumltten that is better oxygenation shallower water andpossibly higher productivity

Summary

The Spence Shale of northeastern Utah and southeastern Idahopreserves a diverse well-skeletonized and soft-bodied biota of earlymiddle Cambrian (Miaolingian Wuliuan) age It provides insightinto marine life in Laurentia just before the time of the WalcottQuarry of the Burgess Shale Notably although older than theBurgess Shale and the Wheeler Marjum andWeeks formations theSpence Shale shares several taxa with these deposits as well as withthe older Pioche Formation in Nevada (supplementary material) Itseems that during this interval soft-bodied arthropods (Hendrickset al 2008) and soft-bodied taxa in general (Hendricks 2013)showed less evolutionary volatility (sensu Lieberman amp Melott2013) than trilobites Let us consider the trilobites which show avery high degree of turnover of 128 species that occur in soft-bodied deposits globally not a single species persists for more thanone stage (Hendricks et al 2008) By contrast among 156 speciesof soft-bodied arthropods 16 species persist for more than onestage and some of these persisted for several stages (Hendrickset al 2008) Ultimately unravelling macroevolutionary patterns intaxa occurring in soft-bodied deposits such as the Spence Shale willprobably prove useful for evaluating various hypotheses about thenature and timing of the Cambrian radiation (for discussion of someof these hypotheses see Lieberman amp Cartwright 2011 Daley et al2018) In addition progress recently has been made in under-standing the geographical distribution of various fossils in theSpence Shale but much more information is needed about thestratigraphic and sedimentological context of fossils within andacross localities (Box 4) Only then will it be possible to work outthe various taphonomic pathways that allowed soft-bodied preser-vation in this key window of Cambrian life

Acknowledgements We thank P Donoghue (University of Bristol) forinviting us to write this paper This contribution would not have been possiblewithout the dedication and generosity of the Gunther family as well as P Jamisonand P Reese who have donated a large number of excellent specimens to the

University of Kansas and other institutions we gratefully acknowledge theirefforts and generosity We thank J Ortega-Hernaacutendez and R Lerosey-Aubril forhelpful reviews and R Lerosey-Aubril for assistance with the figures Thanks goto R LaVine and M Witte (University of Chicago) and J Skabelund fordiscussions and assistance in the field

Funding This research was supported by a Paleontological Society ArthurJames Boucot Research Grant and an Association of Earth Science Clubs ofGreater Kansas City Research Grant to JK

Scientific editing by Philip Donoghue

Correction Notice Error bars have been added to Fig 5g and h The EditorialOffice apologies for this error

ReferencesAllison PA 1988 The role of anoxia in the decay and mineralization of

proteinaceous macrofossils Paleobiology 14 139ndash154Babcock LE amp Robison RA 1988 Taxonomy and paleobiology of some

Middle Cambrian Scenella (Cnidaria) and hyolithids (Mollusca) fromwesternNorth America University of Kansas Paleontological Contributions 121

Brett CE Allison PA DeSantis MK Liddell WD amp Kramer A 2009Sequence stratigraphy cyclic facies and lagerstaumltten in the Middle CambrianWheeler and Marjum Formations Great Basin Utah PalaeogeographyPalaeoclimatology Palaeoecology 277 9ndash33 httpsdoiorg101016jpalaeo200902010

Briggs DEG amp Robison RA 1984 Exceptionally preserved nontrilobitearthropods and Anomalocaris from the middle Cambrian of Utah Universityof Kansas Paleontological Contributions 111

Briggs DEG Lieberman BS Halgedahl SL amp Jarrard RD 2005 A newvetulicolian from the Middle Cambrian of Utah and the phylogenetic positionof a problematic group Palaeontology 48 681ndash686 httpsdoiorg101111j1475-4983200500489x

Briggs DEG Lieberman BS Hendricks JR Halgedahl SL amp JarrardRD 2008 Middle Cambrian arthropods from Utah Journal of Paleontology82 238ndash254 httpsdoiorg10166606-0861

Broce JS amp Schiffbauer JD 2017 Taphonomic analysis of Cambrianvermiform fossils of Utah and Nevada and implications for the chemistry ofBurgess Shale-type preservation PALAIOS 32 600ndash619 httpsdoiorg102110palo2017011

Butterfield NJ Balthasar UWE ampWilson LA 2007 Fossil diagenesis in theBurgess Shale Palaeontology 50 537ndash543 httpsdoiorg101111j1475-4983200700656x

Campbell DP 1974 Biostratigraphy of the Albert ella and Glossopleura zones(lower Middle Cambrian) of northern Utah and southern Idaho Ms thesisUniversity of Utah

Caron J-B amp Jackson DA 2008 Paleoecology of the Greater Phyllopod Bedcommunity Burgess Shale Palaeogeography PalaeoclimatologyPalaeoecology 258 222ndash256 httpsdoiorg101016jpalaeo200705023

Church SB Rigby JK Gunther LF amp Gunther VG 1999 A largeProtospongia hicksi Hinde 1887 from the Middle Cambrian Spence Shale ofSoutheastern Idaho Brigham Young University Geology Studies 44 17ndash25

Conway Morris S amp Robison RA 1982 The enigmatic medusoid Peytoia anda comparison of some Cambrian biotas Journal of Paleontology 56116ndash122 httpsdoiorgwwwjstororgstable1304497

Conway Morris S amp Robison RA 1986 Middle Cambrian priapulids andother soft-bodied fossils from Utah and Spain University of KansasPaleontological Contributions 117

Conway Morris S amp Robison RA 1988 More soft-bodied animals and algaefrom the Middle Cambrian of Utah and British Columbia University ofKansas Paleontological Contributions 122

Conway Morris S Halgedahl SL Selden P amp Jarrard RD 2015a Rareprimitive deuterostomes from the Cambrian (Series 3) of Utah Journal ofPaleontology 89 631ndash636 httpsdoiorg101017jpa201540

Conway Morris S Selden PA Gunther G Jamison PG amp Robison RA2015b New records of Burgess Shale-type taxa from the middle Cambrian ofUtah Journal of Paleontology 89 411ndash423 httpsdoiorg101017jpa201526

Daley AC Antcliffe JB Drage HB amp Pates S 2018 Early fossil record ofEuarthropoda and the Cambrian Explosion Proceedings of the NationalAcademy of Sciences of the USA 115 5323ndash5331 httpsdoiorg101073pnas1719962115

Deiss CH 1938 Cambrian formations and sections in part of CordilleranTrough Geological Society of America Bulletin 49 1067ndash1168 httpsdoiorg101130GSAB-49-1067

Egenhoff SO amp Fishman NS 2013 Traces in the dark sedimentary processesand facies gradients in the upper shale member of the Upper DevonianndashLowerMississippian Bakken Formation Williston Basin North Dakota USAJournal of Sedimentary Research 83 803ndash824 httpsdoiorg102110jsr201360

Elrick M amp Snider AC 2002 Deep-water stratigraphic cyclicity and carbonatemud mound development in the Middle Cambrian Marjum Formation House

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Range Utah USA Sedimentology 49 1021ndash1047 httpsdoiorg101046j1365-3091200200488x

Foster JR amp Gaines RR 2016 Taphonomy and paleoecology of the lsquoMiddlersquoCambrian (Series 3) formations in Utahrsquos West Desert recent finds and newdata In Comer JB Inkenbrandt PC Krahulec KA amp Pinnell ML (eds)Resources and Geology of Utahrsquos West Desert Utah Geological AssociationPublications 45 291ndash336

Gabbott SE Zalasiewicz J amp Collins D 2008 Sedimentation of thePhyllopod Bed within the Cambrian Burgess Shale Formation of BritishColumbia Journal of the Geological Society London 165 307ndash318 httpsdoiorg1011440016-76492007-023

Gaines RR 2014 Burgess Shale-type preservation and its distribution in spaceand time In Laflamme M Schiffbauer JD amp Darroch SAF (eds)Reading and Writing of the Fossil Record Preservational Pathways toExceptional Fossilization Paleontological Society Papers 20 123ndash146

Gaines RR amp Droser ML 2005 New approaches to understanding themechanics of Burgess Shale-type deposits From the micron scale to theglobal picture Sedimentary Record 3 4ndash8 httpsdoiorg102110sedred200524

Gaines RR Kennedy MJ amp Droser ML 2005 A new hypothesis for organicpreservation of Burgess Shale taxa in the middle Cambrian WheelerFormation House Range Utah Palaeogeography PalaeoclimatologyPalaeoecology 220 193ndash205 httpsdoiorg101016jpalaeo200407034

Gaines RR Hammarlund EU et al 2012 Mechanism for Burgess Shale typepreservation Proceedings of the National Academy of Sciences of the USA109 5180ndash5184 httpsdoiorg101073pnas1111784109

Garciacutea-Bellido DC Paterson JR amp Edgecombe GD 2013 Cambrianpalaeoscolecids (Cycloneuralia) from Gondwana and reappraisal of speciesassigned to Palaeoscolex Gondwana Research 24 780ndash795 httpsdoiorg101016jgr201212002

Garson DE Gaines RR Droser ML Liddell WD amp Sappenfield A 2012Dynamic palaeoredox and exceptional preservation in the Cambrian SpenceShale of Utah Lethaia 45 164ndash177 httpsdoiorg101111j1502-3931201100266x

Gunther LF amp Gunther VG 1981 Some Middle Cambrian fossils of UtahBrigham Young University Geology Studies 28 1ndash81

Halgedahl SL Jarrard RD Brett CE amp Allison PA 2009 Geophysical andgeological signatures of relative sea level change in the upper WheelerFormation Drum Mountains WestndashCentral Utah a perspective intoexceptional preservation of fossils Palaeogeography PalaeoclimatologyPalaeoecology 227 34ndash56 httpsdoiorg101016jpalaeo200902011

Hammersburg SR Hasiotis ST amp Robison RR 2018 Ichnotaxonomy of theCambrian Spence Shale Member of the Langston Formation WellsvilleMountains Northern Utah USA Paleontological Contributions 20 1ndash66httpsdoiorg1017161180826428

Handle KC amp Powell WG 2012 Morphologically simple enigmatic fossilsfrom the Wheeler Formation A comparison with definitive algal fossilsPALAIOS 27 304ndash316 httpsdoiorg102110palo2011p11-068r

Hendricks JR 2013 Global distributional dynamics of Cambrian clades asrevealed by Burgess Shale-type deposits In Harper DAT amp Servais T(eds) Early Palaeozoic Biogeography and Palaeogeography GeologicalSociety London Memoirs 38 35ndash43 httpsdoiorg101144M384

Hendricks JR Lieberman BS amp Stigall AL 2008 Using GIS to study thepaleobiogeography of soft-bodied Cambrian arthropods PalaeogeographyPalaeoclimatology Palaeoecology 264 163ndash175 httpsdoiorg101016jpalaeo200804014

Hintze LF amp Kowallis BJ 2009 Geologic history of Utah Brigham YoungUniversity Geology Studies Special Publications 9

Hou XG Siveter DJ et al 2017 The Cambrian Fossils of Chengjiang Chinathe Flowering of Early Animal Life 2nd ed Wiley New York

Kimmig J amp Pratt BR 2015 Soft-bodied biota from the middle Cambrian(Drumian) Rockslide FormationMackenzieMountains northwestern CanadaJournal of Paleontology 89 51ndash71 httpsdoiorg101017jpa20145

Kimmig J amp Pratt BR 2016 Taphonomy of the middle Cambrian (Drumian)Ravens Throat River Lagerstaumltte Rockslide Formation northwestern CanadaLethaia 49 150ndash169 httpsdoiorg101111let12135

Kimmig J amp Pratt BR 2018 Coprolites in the Ravens Throat River Lagerstaumltteof northwestern Canada Implications for the middle Cambrian food webPALAIOS 33 125ndash140 httpsdoiorg102110palo2017038

Kimmig J amp Strotz LC 2017 Coprolites in mid-Cambrian (Series 2ndash3)Burgess Shale-type deposits of Nevada and Utah and their ecologicalimplications Bulletin of Geosciences 92 297ndash309 httpsdoiorg103140bullgeosci1667

Kimmig J Strotz LC amp Lieberman BS 2017 The stalked filter feederSiphusauctum lloydguntheri n sp from the middle Cambrian (Series 3 Stage5) Spence Shale of Utah its biological affinities and taphonomy Journal ofPaleontology 91 902ndash910 httpsdoiorg101017jpa201757

Kimmig J Strotz LC Kimmig SR Egenhoff SO amp Bruce Lieberman BS2018 The middle Cambrian Spence Shale (Series 3 Stage 5) Lagerstaumltte akey Cambrian ecosystem The Fossil Week Abstract Book 5th InternationalPalaeontological Congress 489

Kloss TJ Dornbos SQ Chen JY McHenry LJ amp Marenco PJ 2015High-resolution geochemical evidence for oxic bottom waters in threeCambrian Burgess Shale-type deposits Palaeogeography PalaeoclimatologyPalaeoecology 440 90ndash95 httpsdoiorg101016jpalaeo201508048

Legg DA amp Pates S 2017 A restudy of Utahcaris orion (Euarthropoda) fromthe Spence Shale (Middle Cambrian Utah USA)Geological Magazine 154181ndash186 httpsdoiorg101017S0016756816000789

Lerosey-Aubril R 2015 Notchia weugi gen et sp nov a new short-headedarthropod from the Weeks Formation Konservat-Lagerstaumltte (CambrianUtah) Geological Magazine 152 351ndash357 httpsdoiorg101017S0016756814000375

Lerosey-Aubril R Hegna TA Kier C Bonino E Habersetzer J amp CarreacuteM 2012 Controls on gut phosphatisation the trilobites from the WeeksFormation Lagerstaumltte (Cambrian Utah) PLoS One 7 e32934 httpsdoiorg101371journalpone0032934

Lerosey-Aubril R Ortega-Hernaacutendez J Kier C amp Bonino E 2013Occurrence of the Ordovician-type aglaspidid Tremaglaspis in theCambrian Weeks Formation (Utah USA) Geological Magazine 150945ndash951 httpsdoiorg101017S001675681300037X

Lerosey-Aubril R Hegna TA Babcock LE Bonino E amp Kier C 2014Arthropod appendages from theWeeks Formation Konservat-Lagerstaumltte newoccurrences of anomalocaridids in the Cambrian of Utah USA Bulletin ofGeosciences 89 269ndash282 httpsdoiorg103140bullgeosci1442

Lerosey-Aubril R Gaines RR Hegna TA Ortega-Hernaacutendez J Van RoyP Kier C amp Bonino E 2018 The Weeks Formation Konservat-Lagerstaumltteand the evolutionary transition of Cambrian marine life Journal of theGeological Society London 175 705ndash715 httpsdoiorg101144jgs2018-042

Liddell WD Wright SH amp Brett CE 1997 Sequence stratigraphy andpaleoecology of the Middle Cambrian Spence Shale in northern Utah andsouthern Idaho Brigham Young University Geology Studies 42 59ndash78

Lieberman BS 2003 A new soft-bodied fauna The Pioche Formation ofNevada Journal of Paleontology 77 674ndash690 httpsdoiorg1016660022-3360(2003)077lt0674ANSFTPgt20CO2

Lieberman BS amp Cartwright P 2011 Macroevolutionary patterns andprocesses during the Cambrian radiation integrating evidence from fossilsand molecules Acoreana 7 15ndash38

Lieberman BS amp Kimmig J 2018 Museums paleontology and a biodiversityscience-based approach In Rosenberg GD amp Clary RM (eds)Museums atthe Forefront of the History and Philosophy of Geology HistoryMade Historyin the Making Geological Society of America Special Papers 535 335ndash348

Lieberman BS amp Melott AL 2013 Declining volatility a general property ofdisparate systems from fossils to stocks to the stars Palaeontology 561297ndash1304 httpsdoiorg101111pala12017

LoDuca ST Bykova N Wu M Xiao S amp Zhao Y 2017 Seaweedmorphology and ecology during the great animal diversification events of theearly Paleozoic a tale of two floras Geobiology 15 588ndash616 httpsdoiorg101111gbi12244

Maletz J amp Steiner M 2015 Graptolite (Hemichordata Pterobranchia)preservation and identification in the Cambrian Series 3 Palaeontology 581073ndash1107 httpsdoiorg101111pala12200

Maxey GB 1958 Lower and middle Cambrian stratigraphy in northern Utahand southeastern IdahoGeological Society of America Bulletin 69 647ndash688httpsdoiorg1011300016-7606(1958)69[647LAMCSI]20CO2

Moysiuk J Smith MR amp Caron J-B 2017 Hyoliths are Palaeozoiclophophorates Nature 541 394ndash397 httpsdoiorg101038nature20804

Muscente AD Schiffbauer JD et al 2017 Exceptionally preserved fossilassemblages through geologic time and space Gondwana Research 48164ndash188 httpsdoiorg101016jgr201704020

Nanglu K Caron J-B Conway Morris S amp Cameron CB 2016 Cambriansuspension-feeding tubicolous hemichordates BMC Biology 14 56 httpsdoiorg101186s12915-016-0271-4

Oriel SS amp Armstrong FC 1971 Uppermost Precambrian and LowermostCambrian Rocks in Southeastern Idaho US Geological Survey ProfessionalPapers 394

Ortega-Hernaacutendez J Lerosey-Aubril R Kier C amp Bonino E 2015 A rarenon-trilobite artiopodan from the Guzhangian (Cambrian Series 3) WeeksFormation Konservat-Lagerstaumltte in Utah USA Palaeontology 58 265ndash276httpsdoiorg101111pala12136

Palmer AR 1971 The Cambrian of the Great Basin and adjacent areas westernUnited States In Holland CN (ed) Cambrian of the New World Wiley-Interscience London 1ndash78

Paterson JR Garciacutea-Bellido DC Jago JB Gehling JG Lee MSY ampEdgecombe GD 2016 The Emu Bay Shale Konservat-Lagerstaumltte a view ofCambrian life from East Gondwana Journal of the Geological SocietyLondon 173 1ndash11 httpsdoiorg101144jgs2015-083

Pates S amp Daley AC 2017Caryosyntrips a radiodontan from the Cambrian ofSpain USA and Canada Papers in Palaeontology 3 461ndash470 httpsdoiorg101002spp21084

Pates S amp Daley AC In press The Kinzers Formation (Pennsylvania USA)the most diverse assemblage of Cambrian Stage 4 radiodonts GeologicalMagazine corrected proof online July 30 2018 httpsdoiorg101017S0016756818000547

Pates S Daley AC amp Lieberman BS 2018 Hurdiid radiodontans from themiddle Cambrian (Series 3) of Utah Journal of Paleontology 92 99ndash113httpsdoiorg101017jpa201711

Pratt BR amp Kimmig J 2019 Extensive bioturbation in a middle CambrianBurgess Shale-type fossil Lagerstaumltte in northwestern Canada Geology 47231ndash234 httpsdoiorg101130G455511

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Resser CE 1939 The Spence Shale and its fauna Smithsonian MiscellaneousCollections 97

Rigby JK 1980 The new Middle Cambrian sponge Vauxia magna from theSpence Shale of northern Utah and taxonomic position of the VauxiidaeJournal of Paleontology 54 234ndash240

Robison RA 1965 Middle Cambrian eocrinoids from western North AmericaJournal of Paleontology 39 355ndash364

Robison RA 1969 Annelids from the Middle Cambrian Spence Shale of UtahJournal of Paleontology 43 1169ndash1173

Robison RA 1991 Middle Cambrian biotic diversity examples from four UtahLagerstaumltten In Simonetta AM amp Conway-Morris S (eds) The EarlyEvolution of Metazoa and the Significance of Problematic Taxa CambridgeUniversity Press Cambridge 77ndash98

Robison RA amp Babcock LE 2011 Systematics paleobiology andtaphonomy of some exceptionally preserved trilobites from CambrianLagerstaumltten of Utah Paleontological Contributions 5 1ndash47 httpsdoiorg1017161PC18088543

Robison RA amp Richards BC 1981 Large bivalved arthropods from theMiddle Cambrian of Utah University of Kansas PaleontologicalContribution 106

Robison RA Babcock LE amp Gunther VG 2015 Exceptional CambrianFossils from Utah A window into the age of trilobites Utah GeologicalSurvey Miscellaneous Publications 15

Sprinkle J amp Collins D 2006 New eocrinoids from the Burgess Shale southernBritishColumbia Canada and the Spence Shale northernUtah USACanadianJournal of Earth Sciences 43 303ndash322 httpsdoiorg101139e05-107

Sumrall CD amp Sprinkle J 1999 Ponticulocarpus a new cornuted gradestylophoran from the Middle Cambrian Spence Shale of Utah Journal ofPaleontology 73 886ndash891 httpsdoiorg101017S0022336000040725

Van Roy P Briggs DEG amp Gaines RR 2015 The Fezouata fossils ofMorocco an extraordinary record of marine life in the Early OrdovicianJournal of the Geological Society London 172 541ndash549 httpsdoiorg101144jgs2015-017

Walcott CD 1908 Cambrian Geology and Palaeontology SmithsonianMuseum Miscellaneous Collections 53

Yang J Ortega-Hernaacutendez J Gerber S Butterfield NJ Hou J-B Lan Tamp Zhang X-G 2015 A superarmored lobopodian from the Cambrian ofChina and early disparity in the evolution of Onychophora Proceedings of theNational Academy of Sciences of the USA 112 8678ndash8683 httpsdoiorg101073pnas1505596112

619The Spence Shale Lagerstaumltte

by guest on July 4 2020httpjgslyellcollectionorgDownloaded from