Skip to main content Accessibility help

Bivalved arthropods from the Middle Ordovician Winneshiek Lagerstätte, Iowa, USA

  • Derek E.G. Briggs (a1), Huaibao P. Liu (a2), Robert M. McKay (a2) and Brian J. Witzke (a3)


The Middle Ordovician (Darriwilian) Winneshiek Lagerstätte of northeast Iowa is preserved in a meteorite crater. Besides conodonts, the fossils are dominated by arthropods, particularly eurypterids and phyllocarids. Here we describe the bivalved forms, which include at least seven different taxa. The small phyllocarid Ceratiocaris winneshiekensis, new species, is the most abundant; it is the oldest representative of the Ceratiocarididae. A single incomplete abdomen and telson bearing furcal rami is reminiscent of notostracan branchiopods but its affinities are unknown. Decoracaris hildebrandi, new genus and species, is a rare form with a shield that extends anteriorly into a swollen horn and reaches lengths of 9 cm: it may represent a thylacocephalan crustacean but this cannot be confirmed without soft parts. Iosuperstes collisionis, new genus and species, is represented by suboval valves 10–25 mm long: its affinities are unknown. A probable leperditicopid, which ranges in length from 8 to 18 mm, is commonly preserved in a ‘butterflied’ configuration. It does not preserve the scars and sinuses characteristic of three-dimensionally preserved leperditicopids from elsewhere. Finally the fauna includes at least three ostracods, including a palaeocope with a granular surface and relief similar to Lomatopisthia, and a smooth ?podocope. The Winneshiek fauna differs from those of other Ordovician Lagerstätten from restricted settings such as Airport Cove and William Lake in Manitoba (Katian) where, apart from ostracods, bivalved arthropods are absent, and Silurian examples such as Brandon Bridge (Telychian), which lacks eurypterids, and the Williamsville Member of the Bertie Formation (Pridoli) where conodont assemblages are absent.



Hide All
Aldridge, R.J., Theron, J.N., and Gabbott, S.E., 1994, The Soom Shale: a unique Ordovician fossil horizon in South Africa: Geology Today, v. 10, p. 218221.
Aldridge, R.J., Gabbott, S.E., and Theron, J.N., 2001, The Soom Shale, in Briggs, D.E.G., and Crowther, P.R., eds., Palaeobiology II, Oxford, UK, Blackwell Science, p. 340342.
Allison, P.A., and Briggs, D.E.G., 1993, Exceptional fossil record: distribution of soft-tissue preservation through the Phanerozoic: Geology, v. 21, p. 527530.
Becker, G., 2005, Functional morphology of Palaeozoic ostracods: phylogenetic implications: Hydrobiologia, v. 538, p. 2353.
Berdan, J.M., 1976, Middle Ordovician leperditicopid ostracodes from the Ibex Area, Millard County, Western Utah: Brigham Young University Geology Studies, v. 23, p. 3765.
Berdan, J.M., 1984, Leperditicopid ostracodes from Ordovician rocks of Kentucky and nearby states and characteristic features of the Order Leperditicopida: U.S. Geological Survey Professional Paper, 1066–J, 40 p. + 11 plates.
Bergmann, A., and Rust, J., 2014, Morphology, palaeobiology and phylogeny of Oryctocaris balssi gen. nov. (Arthropoda), a phyllocarid from the Lower Devonian Hunsrück Slate (Germany): Journal of Systematic Palaeontology, v. 12, p. 427444.
Bergström, J., Briggs, D.E.G., Dahl, E., Rolfe, W.D.I., and Stürmer, W., 1987, Nahecaris stuertzi, a phyllocarid crustacean from the Lower Devonian Hunsrück Slate: Paläontologisches Zeitschrift, v. 61, p. 273298.
Braddy, S.J., 2001, Eurypterid palaeoecology: palaeobiological, ichnological and comparative evidence for a ‘mass-moult-mate’ hypothesis: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 172, p. 115132.
Briggs, D.E.G., 1977, Bivalved arthropods from the Middle Cambrian Burgess Shale of British Columbia: Palaeontology, v. 20, p. 595621.
Briggs, D.E.G., 1978, The morphology, mode of life and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), Middle Cambrian, Burgess Shale: Philosophical Transactions of the Royal Society, London B, v. 281, p. 439487.
Briggs, D.E.G., 1983, Affinities and early evolution of the Crustacea: the evidence of the Cambrian fossils, in Schram, F.R., ed., Crustacean Phylogeny, Rotterdam, A.A. Balkema, p. 122.
Briggs, D.E.G., and Rolfe, W.D.I., 1983, New Concavicarida (new order: ? Crustacea) from the Upper Devonian of Gogo, Western Australia, and the palaeoecology and affinities of the group: Special Papers in Palaeontology, v. 30, p. 249276.
Briggs, D.E.G., Clark, N.D.L., and Clarkson, E.N.K., 1991a, The Granton “shrimp-bed”, Edinburgh—a Lower Carboniferous Konservat-Lagerstätte: Transactions of the Royal Society of Edinburgh, Earth Sciences, v. 82, p. 6585.
Briggs, D.E.G., Bottrell, S.H., and Raiswell, R., 1991b, Pyritization of soft-bodied fossils: Beecher’s Trilobite Bed, Upper Ordovician, New York State: Geology, v. 19, p. 12211224.
Briggs, D.E.G., Sutton, M.D., and Siveter, D.J., 2004, A new phyllocarid (Crustacea: Phyllocarida) from the Silurian Fossil-Lagerstätte of Herefordshire, England: Proceedings of the Royal Society, London B, v. 271, p. 131138.
Brünnich, M.T., 1772, Zoologiæ fundamenta prælectionibus academicis accomodata: Grunde i Dyrelaeren, Copenhagen and Leipzig, Fridericus Christianus Pelt, 254 p.
Caster, K.E., and Brooks, H.K., 1956, New fossils from the Canadian-Chazyan (Ordovician) hiatus in Tennessee: Bulletins of American Paleontology, v. 36, p. 157199.
Chlupáč, I., 1992, New aristozoid crustaceans from the Lower Devonian of Bohemia: Casopis pro Mineralogii a Geologii, v. 37, p. 289296.
Collette, J.H., and Rudkin, D.M., 2010a, Phyllocarid crustaceans from the Silurian Eramosa Lagerstätte (Ontario, Canada): taxonomy and functional morphology: Journal of Paleontology, v. 84, p. 118127.
Collette, J.H., and Hagadorn, J.W., 2010b, Three-dimensionally preserved arthropods from Cambrian Lagerstätten of Quebec and Wisconsin: Journal of Paleontology, v. 84, p. 646667.
Collette, J.H., and Hagadorn, J.W., 2010c, The early evolution of phyllocarid arthropods: phylogeny and systematics of Cambrian-Devonian archaeostracans: Journal of Paleontology, v. 84, p. 795820.
Conway Morris, S., 1986, The community structure of the Middle Cambrian Phyllopod Bed (Burgess Shale): Palaeontology, v. 29, p. 423467.
Daley, A.C., Budd, G.E., and Caron, J.-B., 2013, Morphology and systematics of the anomalocaridid arthropod Hurdia from the Middle Cambrian of British Columbia and Utah: Journal of Systematic Palaeontology, v. 11, p. 743787.
Dzik, J., 1980, Isolated mandibles of Early Palaeozoic phyllocarid Crustacea: Neues Jahrbuch für Geologie und Paläontologie Monatshefte, v. 1980, p. 87106.
French, B.M., Cordua, W.S., and Plescia, J.B., 2004, The Rock Elm meteorite impact structure, Wisconsin: geology and shock metamorphic effects in quartz: Geological Society of America Bulletin, v. 116, p. 200218.
Fu, D.-J., and Zhang, X.-L., 2011, A new arthropod Jugatacaris agilis n. gen. n. sp. from the Early Cambrian Chengjiang Biota, South China: Journal of Paleontology, v. 85, p. 567586.
Gaines, R.R., Hammarlund, E.U., Hou, X.-G., Qi, C.-S., Gabbott, S.E., Zhao, Y.-L., Peng, J., and Canfield, D.E., 2012, Mechanism for Burgess Shale–type preservation: Proceedings of the National Academy of Sciences, USA, v. 109, p. 51805184.
Guber, A.L., and Jaanusson, V., 1964, Ordovician ostracodes with posterior domiciliar dimorphism: Bulletin of the Geological Institutions of the University of Uppsala, v. 42, 43 pp.
Hannibal, J.T., and Feldmann, R.M., 1997, Phyllocarid crustaceans from a Middle Ordovician Black Shale within the Ames Structure, northwest Oklahoma, in Johnson, K.S., and Campbell, J.A., eds., Ames Structure in Northwest Oklahoma and Similar Features: Origin and Petroleum Production (1995 Symposium): Oklahoma Geological Survey Circular, v. 100, p. 370373.
Hairapetian, V., Mohibullah, M., Tilley, L.G, Williams, M., Miller, C.G., Afzal, J., Pour, M.G., and Hejazi, S.H., 2011, Early Silurian carbonate platform ostracods from Iran: a peri-Gondwanan fauna with strong Laurentian affinities: Gondwana Research, v. 20, 645653.
Harris, R.W., 1957, Ostracoda of the Simpson Group: Bulletin of the Oklahoma Geological Survey, v. 75, p. 1133.
Haug, C., Briggs, D.E.G., Mikulic, D.G., Kluessendorf, J., and Haug, J.T., 2014, A Silurian thylacocephalan crustacean from Wisconsin, USA, and the functional morphology and systematic affinities of the group: BMC Evolutionary Biology, v. 14, p. 159.
Hawkins, A.D., Xiao, S., Liu, H., and Briggs, D.E.G., 2013, Phosphatization of vermiform fossils from the Winneshiek Lagerstätte, Winneshiek Shale, northeast Iowa: Geological Society of America Abstracts with Programs, v. 45, p. 694.
Henningsmoen, G., 1953, Classification of Palaeozoic straight-hinged ostracods: Norsk Geologisk Tidsskrift, v. 33, p. 4168.
Hessler, R.R., 1964, The Cephalocarida—comparative skeletomusculature: Memoirs of the Connecticut Academy of Arts and Sciences, v. 16, p. 197.
Hickerson, W.J., and Sivill, D.K., 1997, A Konservat-Lagerstaette from the Silurian of eastern Iowa: Geological Society of America, Abstracts with Programs, v. 29, p. 20.
Hou, X.-G., and Bergström, J., 1997, Arthropods of the Lower Cambrian Chengjiang fauna, southwest China: Fossils and Strata, v. 45, p. 1116.
Hou, X.-G., Bergström, J., and Xu, G.-H., 2004, The Lower Cambrian crustacean Pectocaris from the Chengjiang Biota, Yunnan, China: Journal of Paleontology, v. 78, p. 700708.
John, D.L., Hughes, N.C., Galaviz, M.I., Gunderson, G.O., and Meyer, R., 2010, Unusually preserved Metaconularia manni (Roy, 1935) from the Silurian of Iowa, and the systematics of the genus: Journal of Paleontology, v. 84, p. 131.
Johnson, K.S., and Campbell, J.A., 1997, Ames structure in northwest Oklahoma and similar features: origin and petroleum production (1995 Symposium): Oklahoma Geological Survey Circular, v. 100, p. 1396.
Jones, T.R., 1856, Notes on the Palaeozoic bivalved Entomostraca no. 3, some species of Leperditia: Annals and Magazine of Natural History, series 2, v. 17, p. 81101.
Kanygin, A.V., 1971, Ordovician ostracods and biostratigraphy of the Sette-Daban ridge (Mountain Sistem Verchojan): Trudy Instituta Geologii i Geofiziki, Akademia Nauk SSSR, Sibirskoe Otdelenie, v. 128, 1110.
Kluessendorf, J., 1994, Predictability of Silurian Fossil-Konservat-Lagerstätten in North America: Lethaia, v. 27, p. 337344.
Knox, L.W., 2001, Ostracodes as indicators of brackish water environments in the Catskill Magnafacies (Devonian) of New York State: reply: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 171, p. 8183.
Knox, L.W., and Gordon, E.A., 1999, Ostracodes as indicators of brackish water environments in the Catskill Magnafacies (Devonian) of New York State: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 148, p. 922.
Koontz, H., and McKay, R., 2013, Iowa meteorite crater confirmed: (Accessed March 2016).
Kraft, J.C., 1962, Morphologic and systematic relationships of some Middle Ordovician Ostracoda: Geological Society of America Memoir, v. 86, p. 1104.
Lagebro, L., Gueriau, P., Hegna, T.A., Rabet, A., Butler, A., and Budd, G.E., 2015, The oldest notostracan (Strud locality, Upper Devonian, Belgium): Palaeontology, v. 58, p. 497509.
Lamsdell, J.C., Briggs, D.E.G., Liu, H., Witzke, B.J., and McKay, R.M., 2015a, The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa: BMC Evolutionary Biology, v. 15, p. 169.
Lamsdell, J.C., Briggs, D.E.G., Liu, H., Witzke, B.J., and McKay, R.M., 2015b, A new Ordovician arthropod from the Winnishiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspids: The Science of Nature, v. 102, p. 63.
Latreille, P.A., 1802, Histoire naturelle des Crustacés et des Insectes, 3, Familles naturelles des genres: Paris, 468 pp.
Legg, D.A., and Caron, J.-B., 2014, New Middle Cambrian bivalved arthropods from the Burgess Shale (British Columbia, Canada): Palaeontology, v. 57, p. 691711.
Legg, D.A., Sutton, M.D., Edgecombe, G.D., and Caron, J.-B., 2012, Cambrian bivalved arthropod reveals origin of arthrodization: Proceedings of the Royal Society, v. B279, p. 46994704.
Liu, H., McKay, R.M., Young, J.N., Witzke, B.J., McVey, K.J., and Liu, X., 2006, A new Lagerstätte from the Middle Ordovician St. Peter Formation in northeast Iowa, USA: Geology, v. 34, p. 969972.
Liu, H., McKay, R.M., Young, J.N., Witzke, B.J., McVey, K.J., and Liu, X., 2007, The Winneshiek Lagerstätte: Acta Palaeontologica Sinica, v. 46(supplement), p. 282285.
Liu, H., McKay, R.M., Witzke, B.J., and Briggs, D.E.G., 2009, The Winneshiek Lagerstätte and its depositional environments: Geological Journal of China Universities, v. 15, p. 285295. [in Chinese with English summary].
M’Coy, F., 1849, On the classification of some British fossil Crustacea, with notices of new forms in the University of Cambridge: Annals and Magazine of Natural History, Series, v. 2(4), p. 412414.
McKay, R.M., Liu, H., Witzke, B.J., French, B.M., and Briggs, D.E.G., 2011, Preservation of the Middle Ordovician Winneshiek Shale in a probable impact crater: Geological Society of America Abstracts with Programs, v. 43, p. 189.
Mikulic, D.G., Briggs, D.E.G., and Kluessendorf, J., 1985, A new exceptionally preserved biota from the lower Silurian of Wisconsin, U.S.A.: Philosophical Transactions of the Royal Society, London B, v. 311, p. 7585.
Mohibullah, M., Williams, M., Vandenbroucke, T.R.A., Sabbe, K., and Zalasiewicz, J.A., 2012, Marine ostracod provinciality in the Late Ordovician of palaeocontinental Laurentia and its environmental and geographical expression: PloS ONE, 7, p. e41682.
Moore, R.A., Briggs, D.E.G., Braddy, S.J., and Shultz, J.W., 2011, Synziphosurines (Xiphosura: Chelicerata) from the Silurian of Iowa: Journal of Paleontology, v. 85, p. 8391.
Nudds, J.R., and Selden, P.A., 2008, Fossil ecosystems of North America: a guide to the sites and their extraordinary biotas: University of Chicago Press, 288 pp.
Oakley, T.H., Wolfe, J.M., Lindgren, A.R., and Zaharoff, A.K., 2012, Phylotranscriptomics to bring the understudied into the fold: monophyletic Ostracoda, fossil placement, and pancrustacean phylogeny: Molecular Biology and Evolution, v. 30, p. 215233.
Packard, A.S. Jr., 1879, The nebaliad Crustacea as types of a new order: American Naturalist, v. 13, p. 128.
Peters, C.W., Middleton, M.D., and Cordua, W.S., 2002, The paleontology of the Rock Elm disturbance: Pierce County, Wisconsin: Geological Society of America, North-Central Section (36th) and Southeastern Section (51st) GSA Joint Annual Meeting, Lexington, Kentucky, Boulder, Colorado, Geological Society of America Abstracts with Programs, v. 34, p. A95.
Pinna, G., Arduini, P., Pesarini, C., and Terruzzi, G., 1982, Thylacocephala: una nuova classe di crostacei fossili: Atti della Societa italiana di Scienze naturali e del Museo civico di Storia naturale di Milano, v. 123, p. 469482.
Racheboeuf, P.R., Crasquin, S., and Brussa, E., 2009, South American Ordovician phyllocarids (Crustacea, Malacostraca): Bulletin of Geosciences, v. 84, p. 377408.
Repetski, J.E., 1997, Conodont age constraints on the Middle Ordovician black shale within the Ames Structure, Major County, Oklahoma, in Johnson, K.S., and Campbell, J.A., eds., Ames Structure in Northwest Oklahoma and Similar Features: Origin and Petroleum Production (1995 Symposium): Oklahoma Geological Survey Circular, v. 100, p. 363369.
Rode, A.L., and Lieberman, B.S., 2002, Phylogenetic and biogeographic analysis of Devonian phyllocarid crustaceans: Journal of Paleontology, v. 76, p. 271286.
Rolfe, W.D.I., 1962a, Two new arthropod carapaces from the Burgess Shale (Middle Cambrian) of Canada: Breviora, v. 160, p. 19.
Rolfe, W.D.I., 1962b, Grosser morphology of the Scottish Silurian phyllocarid crustacean, Ceratiocaris papilio Salter in Murchison: Journal of Paleontology, v. 36, p. 912932.
Rolfe, W.D.I., 1962c, The cuticle of some Middle Silurian ceratiocaridid Crustacea from Scotland: Palaeontology, v. 5, p. 3051.
Rolfe, W.D.I., 1969, Phyllocarida, in Moore, R.C., ed., Treatise on Invertebrate Paleontology, Part R, Arthropoda 4 (1), Lawrence, Kansas, Geological Society of America and University of Kansas Press, p. 296331.
Salter, J.W., 1860, On new fossil Crustacea from the Silurian rocks: Annals and Magazine of Natural History, Series 3(5), p. 153162.
Schram, F.R., 2014, Family level classification within Thylacocephala, with comments on their evolution and possible relationships: Crustaceana, v. 87, p. 340363.
Scott, H.W., 1961, Order Leperditicopida Scott, n. order, in Moore, R.C., ed., Treatise on Invertebrate Paleontology, Part Q, Arthropoda 3, Lawrence, Kansas, Geological Society of America and University of Kansas Press, p. 103110.
Siveter, D.J., Vannier, J.M.C., and Palmer, D., 1987, Silurian myodocopid ostracodes: their depositional environments and the origin of their shell microstructures: Palaeontology, v. 30, p. 783813.
Siveter, D.J., Briggs, D.E.G., Sutton, M.D., and Joomun, S.C., 2013, A Silurian myodocope with preserved soft-parts: cautioning the interpretation of the shell-based ostracod record: Proceedings of the Royal Society, London B, v. 280, p. 20122664.
Siveter, D.J., Tanaka, G., Farrell, U.C., Martin, M.J., Siveter, D.J., and Briggs, D.E.G., 2014, Exceptionally preserved 450-million-year-old Ordovician ostracods with brood care: Current Biology, v. 24, p. 801806.
Tetlie, O.E., Brandt, D.S., and Briggs, D.E.G., 2008, Ecdysis in sea scorpions (Chelicerata: Eurypterida): Palaeogeography, Palaeoclimatology, Palaeoecology, v. 265, p. 182194.
Van Roy, P., and Briggs, D.E.G., 2011, A giant Ordovician anomalocaridid: Nature, v. 473, p. 510513.
Van Roy, P., Briggs, D.E.G., and Gaines, R.R., 2015, The Fezouata fossils of Morocco – an extraordinary record of marine life in the Early Ordovician. Journal of the Geological Society, v. 172, p. 541549.
Van Roy, P., Orr, P.J., Botting, J.P., Muir, L.A., Vinther, J., Lefebvre, B., el Hariri, K., and Briggs, D.E.G., 2010, Ordovician faunas of Burgess Shale-type: Nature, v. 465, p. 215218.
Vannier, J., Boissy, P., and Racheboeuf, P.R., 1997, Locomotion in Nebalia bipes: a possible model for Palaeozoic phyllocarid crustaceans: Lethaia, v. 30, p. 89104.
Vannier, J., Wang, S.Q., and Coen, M., 2001, Leperditicopid arthropods (Ordovician-Late Devonian): functional morphology and ecological range: Journal of Paleontology, v. 75, p. 7595.
Vannier, J., Racheboeuf, P.R., Brussa, E.D., Williams, M., Rushton, A.W.A., Servais, T., and Siveter, D.J., 2003, Cosmopolitan arthropod zooplankton in the Ordovician seas: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 195, p. 173191.
Vannier, J., Chen, J.-Y., Huang, D.-Y., Charbonnier, S., and Wang, X.-Q., 2006, The Early Cambrian origin of thylacocephalan arthropods: Acta Paleontologica Polonica, v. 51, p. 201214.
Vrazo, M.B., Trop, J.M., and Brett, C.E., 2014, A new eurypterid lagerstätte from the Upper Silurian of Pennsylvania: Palaios, v. 29, p. 431448.
Waugh, D.A., Feldmann, R.M., Burrell, J.L., Hull, A.L., Hein, K., and Schweitzer, C.E., 2009, Ontogenetic variations in cuticle morphology in the blue crab Callinectes sapidus Rathbun, 1896: Journal of Crustacean Biology, v. 29, p. 141156.
Williams, M., 1991, On Lomatopisthia simplex (Harris): Stereo-Atlas of Ostracod shells, v. 18, p. 1316.
Williams, M., and Siveter, D.J., 1996, Lithofacies-influenced ostracod associations in the middle Ordovician Bromide Formation, Oklahoma, USA: Journal of Micropalaeontology, v. 15, p. 6981.
Williams, M., and Siveter, D.J., 2008, The earliest leperditicope arthropod: a new genus from the Ordovician of Spitsbergen: Journal of Micropalaeontology, v. 27, p. 97101.
Witzke, B.J., McKay, R.M., Liu, H., and Briggs, D.E.G., 2011, The Middle Ordovician Winneshiek Shale of northeast Iowa: correlation and paleogeographic implications: Geological Society of America Abstracts with Programs, v. 43, p. 315.
Wolter, C.F., McKay, R.M., Liu, H., Bounk, M.J., and Libra, R.D., 2011, Geologic mapping for water quality projects in the Upper Iowa River watershed: Iowa Department of Natural Resources, Iowa Geological and Water Survey Technical Information Series, v. 54, 34 p.
Young, G.A., Rudkin, D.M., Dobrzanski, E.P., Robson, S.P., and Nowlan, G.S., 2007, Exceptionally preserved Late Ordovician biotas from Manitoba, Canada: Geology, v. 35, p. 883886.

Bivalved arthropods from the Middle Ordovician Winneshiek Lagerstätte, Iowa, USA

  • Derek E.G. Briggs (a1), Huaibao P. Liu (a2), Robert M. McKay (a2) and Brian J. Witzke (a3)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed