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Marjum Formation
Stratigraphic range: Middle Cambrian
Notch Peak Sill intruding into the layers of white marble and grey argillite of the Marjum Formation
TypeGeological formation
OverliesWheeler Shale
ThicknessUp to 430 meters[1]
Lithology
Primarylimestone
Othershale, metasedimentary rocks
Location
Region Utah
Country USA
ExtentHouse Range
Type section
Named forMarjum Pass[2]
Named byCharles D. Walcott
Year defined1908[2]

The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah.[1][3] It is named after its type locality, Marjum Pass, and was defined in 1908.[2] The formation is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale,[4] falling in the Ptychagnostus praecurrens trilobite zone.[5]

Fossil content

[edit]
Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Ambulacrarians

[edit]
Ambulacrarians reported from the Marjum Formation
Genus Species Presence Material Notes Images
Castericystis C. vali Numerous specimens.[6] A solutan.
Eldonia E. ludwigi Marjum Pass (Ptychagnostus punctuosus Zone).[7] SM X.50204.1 (part) & SM X.50204.2 (counterpart).[7] A cambroernid.
Marjumicystis M. mettae 7 specimens.[6] An eocrinoid.
Mastigograptus M. sp. A single specimen.[8] A mastigograptid graptolite.
Totiglobus T.? lloydi Locality 811.[9] 1 specimen (USNM 172047).[9] An edrioasteroid.

Arthropods

[edit]
Arthropods reported from the Marjum Formation
Genus Species Presence Material Notes Images
Anomalocaris A. nathorsti Sponge Gully.[10] Partial body (USNM 374593).[10] Species moved to the genus Peytoia.
Asaphiscus A. wheeleri Bathyuriscus fimbriatus Subzone.[11] A ptychopariid trilobite.
Baltagnostus B. eurypyx All subzones of the Bolaspidella Zone.[11] Multiple specimens.[11] A diplagnostid trilobite.
Bathyuriscidella B. aff. B. amplicauda Bolaspidella contracta Subzone.[11] 3 pygidia.[11] A dolichometopid trilobite.
Bathyuriscus B. elegans Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dolichometopid trilobite.
B. fimbriatus Bathyuriscus fimbriatus & lower Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dolichometopid trilobite.
Bolaspidella B. contracta Bolaspidella contracta & lower Lepojyge calva Subzones.[11] A menomoniid trilobite.
B. housensis Bathyuriscus fimbriatus Subzone.[11] A menomoniid trilobite.
B. jarrardi Localities 347, 391, and 716 (mid-Bolaspidella Zone).[12] Multiple specimens.[12] A menomoniid trilobite.
Branchiocaris B. pretiosa Sponge Gully.[10][13] 3 specimens.[10] A hymenocarine.
Buccaspinea B. cooperi Kells Knolls locality.[14] An almost complete specimen (BPM 1108).[14] A hurdiid, originally reported as Hurdia sp.
Burlingia B. halgedahlae Localities 347 and 716 (mid-Bolaspidella Zone).[12] Multiple specimens.[12] A burlingiid trilobite.
Caryosyntrips C. camurus 'Red Wash' locality.[14] 2 isolated frontal appendages.[14] A panarthropod of uncertain classification.
Cotalagnostus C. laevus Bolaspidella contracta Subzone.[11] Over 50 specimens.[11] A diplagnostid trilobite.
C. sp. Bolaspidella contracta Subzone.[11] A pygidium. A diplagnostid trilobite.
Dicranocaris D. guntherorum Red Wash, Modocia Flats & Sponge Gully.[13] 4 specimens.[13] An arthropod of uncertain classification.
Dytikosicula D. desmatae West of Delta, House Range.[7] 1 specimen (SM X.50203).[7] A putative megacheiran.
Elrathia E. alapyge Bolaspidella contracta & Lejopyge calva Subzones.[11] Numerous specimens.[11] A ptychopariid trilobite.
E. marjumi Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Numerous specimens.[11] A ptychopariid trilobite.
Emeraldella E.? sp. Red Wash.[10] Part & counterpart (KUMIP 204791).[10] An artiopod.
Hemirhodon H. amplipyge Bolaspidella contracta Subzone.[11] 14 incomplete specimens.[11] A dolichometopid trilobite.
Holteria H. problematica Marjum Pass (Lejopyge calva Subzone).[11] A pygidium.[11] A corynexochid trilobite.
Homagnostus H. incertus Bolaspidella contracta Subzone.[11] Multiple specimens.[11] An agnostid trilobite.
Hypagnostus H. parvifrons All subzones of the Bolaspidella Assemblage Zone.[11] Numerous specimens.[11] A diplagnostid trilobite.
Itagnostus I. interstrictus House Range.[15] A peronopsid trilobite originally reported as Peronopsis interstricta.
Leanchoilia L.? cf. protogonia Sponge Gully.[13] Part & counterpart of a complete specimen (UU 06011.01).[13] A megacheiran.
Lejopyge L. calva Marjum Pass (Lejopyge calva Subzone).[11] Numerous specimens.[11] A ptychagnostid trilobite.
Linguagnostus L. perplexus Bolaspidella contracta Subzone.[11] Over 20 specimens.[11] A diplagnostid trilobite.
Marjumia M. callas Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
M. typa Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
Modocia M. laevinucha Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Many specimens.[11] A marjumiid trilobite.
M. nuchaspina Bolaspidella contracta Subzone.[11] A marjumiid trilobite.
M. typicalis 50 or more specimens.[11] A marjumiid trilobite.
Naraoia N. compacta Sponge Gully.[16] 4 specimens.[16] A naraoiid.
Neolenus N. inflatus East of Antelope Springs.[17] Multiple specimens & fragments.[17] A trilobite.
N. intermedius East of Antelope Springs.[17] A trilobite.
N. intermedius pugio East of Antelope Springs.[17] 4 specimens of a pygidium.[17] A trilobite.
N. superbus East of Antelope Springs.[17] Multiple specimens & fragments.[17] A trilobite.
Nettapezoura N. basilika Sponge Gully.[13] An arachnomorph.
Olenoides O. decorus Bolaspidella contracta Subzone.[11] 7 specimens.[11] A dorypygid trilobite.
O. inflatus Bolaspidella contracta Subzone.[11] A dorypygid trilobite.
O. marjumensis Bolaspidella contracta Subzone.[11] A dorypygid trilobite.
O. pugio Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A dorypygid trilobite.
O. superbus Bolaspidella contracta Subzone.[11] 7 specimens.[11] A dorypygid trilobite.
Pahvantia P. hastata Precise localities unknown.[14] 3 specimens.[14] A hurdiid.
Peronopsis P. interstricta House Range.[15] Numerous specimens.[11] Reassigned to the genus Itagnostus.
P. segmenta House Range.[15] Multiple specimens.[11] A peronopsid trilobite.
Perspicaris P.? ellipsopelta Ptychagnostus punctuosus Zone.[18] Valves & carapaces.[18] A bivalved arthropod.
Peytoia P. nathorsti Sponge Gully.[10] Partial body (USNM 374593) & partial mouthpart (KUMIP 314095).[19] A hurdiid, formerly named Anomalocaris nathorsti.
Ptychagnostus P. akanthodes Bolaspidella contracta Subzone.[11] Numerous specimens.[11] A ptychagnostid trilobite.
P. atavus House Range.[15] A ptychagnostid trilobite.
P. hybridus Bolaspidella contracta Subzone.[11] About 10 specimens.[11] A ptychagnostid trilobite.
P. richmondensis Bathyuriscus fimbriatus Subzone.[11] Numerous specimens.[11] A ptychagnostid trilobite.
P. sp. Bolaspidella contracta Subzone.[11] At least 5 pygidia. A ptychagnostid trilobite.
Trymataspis T. depressa Bolaspidella contracta Subzone.[11] Over 30 specimens.[11] A lonchocephalid trilobite.
T. lomaleie Bolaspidella contracta Subzone.[11] 10 cranidia.[11] A lonchocephalid trilobite.
T. pristina Bolaspidella contracta Subzone.[11] Over 20 cranidia.[11] A lonchocephalid trilobite.
Tuzoia T. guntheri Ptychagnostus punctuosus Zone.[18] Multiple valves & carapaces.[18][20] A hymenocarine.
Utagnostus U. trispinulus Bolaspidella contracta & Lejopyge calva Subzones.[11] Multiple specimens.[11] An agnostid trilobite.
Utaspis U. marjumensis House Range & Wheeler Amphitheater.[11] A ptychopariid trilobite.
Zacanthoides Z. sp. Wheeler Amphitheater (Bolaspidella contracta Subzone).[11] A cranidium.[11] A zacanthoidid trilobite.

Chancelloriids

[edit]
Chancelloriids reported from the Marjum Formation
Genus Species Presence Material Notes Images
Chancelloria C. sp. Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] About 20 spicules.[11] A chancelloriid.

Chordates

[edit]
Chordates reported from the Marjum Formation
Genus Species Presence Material Notes Images
Megasiphon M. thylakos House Range.[21] One specimen (UMNH.IP.6079).[21] A tunicate.
Nuucichthys N. rhynchocephalus House range.[22] One specimen (UMNH.IP.6084)[22] A basal chordate related to Metaspriggina.
Skeemella S. clavula North of Red Wash (Ptychagnostus punctuosus Biozone).[23] 2 specimens (KUMIP 314102 & KUMIP 314103).[23] A vetulicolian.

Cnidarians

[edit]

Moon, Caron & Moysiuk (2023) considered these fossils would be ctenophores instead.[24]

Cnidarians reported from the Marjum Formation
Genus Species Presence Material Notes Images
Coronatae? Indeterminate Sponge Gully.[25] 1 specimen (UU07021.05).[25] A scyphozoan jellyfish, may be referrable to the crown jellyfish family.
Cubozoa? Indeterminate Sponge Gully.[25] 2 specimens (UU07021.01 & UU07021.02).[25] Specimens possibly referrable to box jellyfish.
Narcomedusae? Indeterminate Sponge Gully.[25] 5 specimens (UU07021.03, UU07021.04, UU07021.06, UU07021.07 & UU07021.08).[25] A hydrozoan tentatively assigned to this family.
Semaeostomeae? Indeterminate Sponge Gully.[25] 2 specimens (UU07021.09 & UU07021.10).[25] A scyphozoan jellyfish tentatively assigned to this family.

Ctenophores

[edit]
Ctenophores reported from the Marjum Formation
Genus Species Presence Material Notes Images
Ctenorhabdotus C. campanelliformis House Range (likely from the lower Ptychagnostus punctuosus Zone).[26] 1 specimen (UMNH.IP.6125).[26] A ctenophore.
Thalassostaphylos T. elegans House Range (lower Ptychagnostus punctuosus Zone).[26] 1 specimen (UMNH.IP.6086).[26] A ctenophore.

Lophotrochozoans

[edit]
Lophotrochozoans reported from the Marjum Formation
Genus Species Presence Material Notes Images
Acrothele A. subsidua Bathyuriscus-Elrathina & Bolaspidella Zones.[11] A brachiopod.
Helcionella "H." arguta Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] More than 100 specimens.[11] A helcionellid.
Hyolithes H. sp. All subzones of the Bolaspidella Zone.[11] More than 100 specimens.[11] A hyolith.
Lingulella L. sp. Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] An obolid brachiopod.
Micromitra M. modesta Multiple specimens.[11] A paterinide brachiopod.
Nisusia N. sulcata 18 specimens.[27] A kutorginate brachiopod.
Pegmatreta P. bellatula Bathyuriscus fimbriatus & Bolaspidella contracta Subzones.[11] Numerous specimens.[11] A brachiopod.
P. ophirensis All subzones of the Bolaspidella Zone.[11] A brachiopod.
Pelagiella P. sp. Bolaspidella contracta Subzone.[11] More than 50 internal molds.[11] A pelagiellid.
Prototreta P. attenuata Bathyuriscus-Elrathina Zone & Bolaspidella Zone.[11] A brachiopod.
P. mimica Bolaspidella contracta Subzone.[11] A brachiopod.
Stenothecoides S. elongata Bathyuriscus fimbriatus Subzone.[11] Over 30 valves.[11] A stenothecoid.

Scalidophorans

[edit]
Scalidophorans reported from the Marjum Formation
Genus Species Presence Material Notes Images
Arrakiscolex A. aasei Grey Marjum locality (Ptychagnostus punctuosus Zone).[28] Cuticle fragments.[28] A palaeoscolecid also known from the Upper Weeks Formation.
Ottoia O. prolifica Sponge Gully.[5] A complete individual (KUMIP 204770).[5] Referral of the specimen to this species is insecure, better classified as O.? sp.[28][29]
O.? sp. Sponge Gully.[28] A complete individual (KUMIP 204770).[28] A stem-priapulid, specimen formerly referred to Ottoia prolifica or Scathascolex minor.[28]
Scathascolex S. minor Sponge Gully.[5] A complete individual (KUMIP 204770).[5][30] Specimen reassigned to Ottoia? sp.[28]
Selkirkia S. willoughbyi Sponge Gully.[5] Tube with associated soft parts (KUMIP 204788).[5] A stem-priapulid.

Sponges

[edit]
Sponges reported from the Marjum Formation
Genus Species Presence Material Notes Images
Choia C. carteri Sponge Gulch.[31] A demosponge.
C. hindei Red Cliffs Wash.[31] 2 specimens & 3 other fragments.[31] A demosponge.
C. utahensis Sponge Gulch.[31] Several specimens.[31] A demosponge.
Diagoniella D. cyathiformis Red Cliffs Wash & Kells Knolls Gulch.[31] Numerous specimens.[31] A reticulosan.
D. hindei Sponge Gulch.[31] Approximately 40 specimens.[31] A reticulosan.
D. magna Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[32] A fragment (USNM 535922).[32] A reticulosan.
D. sp. Sponge Gulch.[31] 2 large fragments.[31] A reticulosan.
Hamptonia H. bowerbanki Red Cliffs Wash & Sponge Gulch.[31] Multiple specimens.[31] A demosponge.
Hazelia H. palmata Near Marjum Pass.[33] One specimen.[33] A demosponge.
Hintzespongia H. bilamina Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[31][32] Multiple specimens.[31][32] A reticulosan.
Hexactinellida Indeterminate Miscellaneous spicules.[11] Indeterminate glass sponges, originally reported as Hyalospongiae (now a junior synonym).
Kiwetinokia Drum Mountains.[31] 4 large slabs.[31] A reticulosan.
Leptomitus L. metta Red Cliffs Wash locality.[31] 22 specimens.[31] A demosponge.
Polygoniella P. turrelli House Range[34] Around 200 specimens[34] A glass sponge
Protospongia P.? elongata Sponge Gulch.[31] 1 specimen.[31] A reticulosan.
Testiispongia T. venula Sponge Gulch.[31] Several specimens.[31] A glass sponge.
Valospongia V. gigantis Sponge Gulch.[31] A reticulosan.
V.? gigantus Kells Knolls Gulch (Bathyuriscus fimbriatus zone).[32] A fragment (USNM 535917).[32] A reticulosan.

See also

[edit]

References

[edit]
  1. ^ a b Foster, John; Gaines, Robert (October 2016). "Taphonomy and paleoecology of the "middle" Cambrian (Series 3) formations in Utah's West Desert: Recent finds and new data". Utah Geological Association Publication. 45: 291–336.
  2. ^ a b c Walcott, Charles D. (1910). "Nomenclature of some cambrian cordilleran formations". Smithsonian Miscellaneous Collections. 53 (1): 1–12. hdl:10088/23377.
  3. ^ "Trilobites of The Marjum Formation".
  4. ^ Robison, R. A. (1964). "Upper Middle Cambrian Stratigraphy of Western Utah". Geological Society of America Bulletin. 75 (10): 995–1010. Bibcode:1964GSAB...75..995R. doi:10.1130/0016-7606(1964)75[995:UMCSOW]2.0.CO;2. ISSN 0016-7606.
  5. ^ a b c d e f g Conway Morris, S.; Robison, R. A. (1986). "Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain". University of Kansas Paleontological Contributions. 117: 1–22. hdl:1808/3696.
  6. ^ a b Ubaghs, G.; Robison, Richard A. (September 1985). "A homoiostelean and a new eocrinoid from the Middle Cambrian of Utah". University of Kansas Paleontological Contributions (115): 1–24.
  7. ^ a b c d Conway Morris, Simon; Selden, Paul A.; Gunther, Glade; Jamison, Paul G.; Robison, Richard A. (May 2015). "New records of Burgess Shale-type taxa from the middle Cambrian of Utah". Journal of Paleontology. 89 (3): 411–423. Bibcode:2015JPal...89..411C. doi:10.1017/jpa.2015.26. ISSN 0022-3360.
  8. ^ LoDuca, Steven T.; Kramer, Anthony (March 2014). "Graptolites from the Wheeler and Marjum Formations (Cambrian, Series 3) of Utah". Journal of Paleontology. 88 (2): 403–410. Bibcode:2014JPal...88..403L. doi:10.1666/12-096. ISSN 0022-3360. S2CID 140553697.
  9. ^ a b Sprinkle, James (January 1985). "New edrioasteroid from the Middle Cambrian of western Utah". University of Kansas Paleontological Contributions. 116: 1–4.
  10. ^ a b c d e f g Briggs, D. E. G.; Robison, Richard A. (January 1984). "Exceptionally preserved nontrilobite arthropods and Anomalocaris from the Middle Cambrian of Utah". University of Kansas Paleontological Contributions. 111: 1–23.
  11. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk bl bm bn bo bp bq br bs bt bu bv bw bx by bz ca cb cc cd ce Robison, Richard A. (1964). "Late Middle Cambrian Faunas from Western Utah". Journal of Paleontology. 38 (3): 510–566. ISSN 0022-3360. JSTOR 1301528.
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  13. ^ a b c d e f Briggs, Derek E. G.; Lieberman, Bruce S.; Hendricks, Jonathan R.; Halgedahl, Susan L.; Jarrard, Richard D. (2008). "Middle Cambrian arthropods from Utah". Journal of Paleontology. 82 (2): 238. Bibcode:2008JPal...82..238B. doi:10.1666/06-086.1. ISSN 0022-3360. S2CID 31568651.
  14. ^ a b c d e f Pates, Stephen; Lerosey-Aubril, Rudy; Daley, Allison C.; Kier, Carlo; Bonino, Enrico; Ortega-Hernández, Javier (2021-01-19). "The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian)". PeerJ. 9: e10509. doi:10.7717/peerj.10509. ISSN 2167-8359. PMC 7821760. PMID 33552709.
  15. ^ a b c d Robison, R. A. (1982). "Some Middle Cambrian Agnostoid Trilobites from Western North America". Journal of Paleontology. 56 (1): 132–160. ISSN 0022-3360. JSTOR 1304500.
  16. ^ a b Robison, Richard A. (1984-07-24). "New Occurrences of the Unusual Trilobite Naraoia From the Cambrian of Idaho and Utah". University of Kansas Paleontological Contributions. 112: 1–8.
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  19. ^ Pates, Stephen; Daley, Allison C.; Lieberman, Bruce S. (January 2018). "Hurdiid radiodontans from the middle Cambrian (Series 3) of Utah". Journal of Paleontology. 92 (1): 99–113. Bibcode:2018JPal...92...99P. doi:10.1017/jpa.2017.11. ISSN 0022-3360. S2CID 135388079.
  20. ^ Vannier, Jean; Caron, Jean-Bernard; Yuan, Jin-Liang; Briggs, Derek E. G.; Collins, Desmond; Zhao, Yuan-Long; Zhu, Mao-Yan (May 2007). "Tuzoia: Morphology and Lifestyle of a Large Bivaled Arthropod of the Cambrian Seas". Journal of Paleontology. 81 (3): 445–471. Bibcode:2007JPal...81..445V. doi:10.1666/pleo05070.1. ISSN 0022-3360. S2CID 197540482.
  21. ^ a b Nanglu, Karma; Lerosey-Aubril, Rudy; Weaver, James C.; Ortega-Hernández, Javier (2023-07-06). "A mid-Cambrian tunicate and the deep origin of the ascidiacean body plan". Nature Communications. 14 (1): 3832. Bibcode:2023NatCo..14.3832N. doi:10.1038/s41467-023-39012-4. ISSN 2041-1723. PMC 10325964. PMID 37414759.
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  23. ^ a b Kimmig, Julien; Leibach, Wade W.; Lieberman, Bruce S. (2020-05-30). "First occurrence of the problematic vetulicolian Skeemella clavula in the Cambrian Marjum Formation of Utah, USA". Carnets de géologie (Notebooks on geology). 20 (10): 215–221. doi:10.4267/2042/70836. hdl:1808/33460. S2CID 219178949.
  24. ^ Moon, Justin; Caron, Jean-Bernard; Moysiuk, Joseph (2023-08-09). "A macroscopic free-swimming medusa from the middle Cambrian Burgess Shale". Proceedings of the Royal Society B: Biological Sciences. 290 (2004). doi:10.1098/rspb.2022.2490. ISSN 0962-8452. PMC 10394413. PMID 37528711.
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  26. ^ a b c d Parry, Luke A.; Lerosey-Aubril, Rudy; Weaver, James C.; Ortega-Hernández, Javier (2021-09-24). "Cambrian comb jellies from Utah illuminate the early evolution of nervous and sensory systems in ctenophores". iScience. 24 (9): 102943. Bibcode:2021iSci...24j2943P. doi:10.1016/j.isci.2021.102943. ISSN 2589-0042. PMC 8426560. PMID 34522849.
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  28. ^ a b c d e f g Leibach, Wade; Lerosey-Aubril, Rudy; Whitaker, Anna; Schiffbauer, James; Kimmig, Julien (September 2021). "First palaeoscolecid from the Cambrian (Miaolingian, Drumian) Marjum Formation of western Utah". Acta Palaeontologica Polonica. 66. doi:10.4202/app.00875.2021.
  29. ^ Smith, Martin R.; Harvey, Thomas H. P.; Butterfield, Nicholas J. (May 2015). Kouchinsky, Artem (ed.). "The macro- and microfossil record of the Cambrian priapulid Ottoia". Palaeontology. 58 (4): 705–721. Bibcode:2015Palgy..58..705S. doi:10.1111/pala.12168. ISSN 0031-0239.
  30. ^ Smith, Martin R. (2015-10-15). Sigwart, Julia (ed.). "A palaeoscolecid worm from the Burgess Shale". Palaeontology. 58 (6): 973–979. Bibcode:2015Palgy..58..973S. doi:10.1111/pala.12210.
  31. ^ a b c d e f g h i j k l m n o p q r s t u v w x Rigby, J. Keith (1983). "Sponges of the Middle Cambrian Marjum Limestone from the House Range and Drum Mountains of Western Millard County, Utah". Journal of Paleontology. 57 (2): 240–270. ISSN 0022-3360. JSTOR 1304651.
  32. ^ a b c d e f Rigby, J. Keith; Church, Stephen B.; Anderson, Nicolle K. (2010). "Middle Cambrian Sponges from the Drum Mountains and House Range in Western Utah". Journal of Paleontology. 84 (1): 66–78. Bibcode:2010JPal...84...66R. doi:10.1666/08-046.1. ISSN 0022-3360. JSTOR 20627693. S2CID 130205628.
  33. ^ a b Rigby, J. Keith; Gunther, Lloyd F.; Gunther, Freida (November 1997). "The first occurrence of the Burgess Shale demosponge Hazelia palmata Walcott, 1920, in the Cambrian of Utah". Journal of Paleontology. 71 (6): 994–997. Bibcode:1997JPal...71..994R. doi:10.1017/S0022336000035976. ISSN 0022-3360. S2CID 130706440.
  34. ^ a b Del Mouro, Lucas; Lerosey-Aubril, Rudy; Botting, Joseph; Coleman, Robert; Gaines, Robert R.; Skabelund, Jacob; Weaver, James C.; Ortega-Hernández, Javier (2024-09-18). "A new sponge from the Marjum Formation of Utah documents the Cambrian origin of the hexactinellid body plan". Royal Society Open Science. 11 (9). doi:10.1098/rsos.231845. ISSN 2054-5703. PMC 11407857. PMID 39295920.
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