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Mobergellans from the early Cambrian of Greenland and Labrador: new morphological details and implications for the functional morphology of mobergellans

Published online by Cambridge University Press:  29 August 2017

Christian B. Skovsted  and
Timothy P. Topper
Christian B. Skovsted
Affiliation:
Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden 〈[email protected]〉
Timothy P. Topper
Affiliation:
Palaeoecosystems Group, Department of Earth Sciences, Durham University, Durham DH1 3LE, UK 〈[email protected]〉
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Abstract

New morphological features of the mobergellan Discinella micans (Billings, 1871) from the lower Cambrian (Stage 4) of Northeast Greenland and southern Labrador are described. The new features include: (1) the morphology of the larval shell, which is shown to be cap-shaped, subcircular, and with impressions of the internal muscle attachment scars; (2) a range of unusual shell deformations (changes in growth direction resulting in thickened shells, partial detachment of shell laminae and subsequent regrowth, internal projections of shell material increasing the depth of the shell by up to 150%, disturbances and irregular fusion of muscle scars). In addition, we provide new details about the variability in number and shape of the anteriormost internal muscle scars, which often fuse and may vary in number from one to three (resulting in nine to 11 scars in total). Together the new observations provide additional strength for the hypothesis that mobergellan shells represent opercula of an as yet unknown tubular organism.

Type
Articles
Information
Journal of Paleontology , Volume 92 , Special Issue 1: Cambrian Explosion , January 2018 , pp. 71 - 79
Copyright
Copyright © 2017, The Paleontological Society 

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References

Bengtson, S., 1968, The problematic genus Mobergella from the lower Cambrian of the Baltic area: Lethaia, v. 1, p. 325–351.Google Scholar
Bengtson, S., Conway Morris, S., Cooper, B.J., Jell, P.A., and Runnegar, B.N., 1990, Early Cambrian fossils from South Australia: Association of Australasian Palaeontologists, Memoir, v. 9, 364 p.Google Scholar
Billings, E., 1871, On some new species of Palaeozoic fossils: Canadian Naturalist, v. 6, p. 213–233, 240.Google Scholar
Chen, Jun-Yuan, Hou, Xian-Gaung, and Lu, Hao-Zhi, 1989, Early Cambrian netted scale-bearing wormlike sea animal: Acta Palaeontologica Sinica, v. 28, p. 1–16.Google Scholar
Conway Morris, S., and Chapman, A.J., 1997, Mobergellans from the lower Cambrian of Mongolia, Sweden, and the United States: Molluscs or opercula of incertae sedis?: Journal of Paleontology, v. 71, p. 968–985.CrossRefGoogle Scholar
Demidenko, Y.E., 2016, Morphology, taxonomic position, and stratigraphic distribution of the early Cambrian skeletal problematics Mobergella radiolata Bengtson, 1968: Paleontological Journal, v. 50, p. 435–449.Google Scholar
Dzik, J., 2010, Brachiopod identity of the alleged monoplacophoran ancestors of cephalopods: Malacologia, v. 52, p. 97–113.Google Scholar
Fisher, D.W., 1962, Small conoidal shells of uncertain affinities, in Moore, R.C., ed., Treatise on Invertebrate Paleontology, Pt. W. Miscellanea. Lawrence, Geological Society of America and University of Kansas Press, p. W98–W143.Google Scholar
Hall, J., 1872, Notes on some new or imperfectly known forms among the Brachiopoda. etc.: Annual Report to the Regents of the University of the State of New York, v. 23, Appendix G, p. 244–247.Google Scholar
Hedström, H., 1923, On “Discinella holsti Mbg” and Scapha and Archaeophiala (some questions on nomenclature): Sveriges Geologiska Undersökning (C), v. 314, 26 p.Google Scholar
Hedström, H., 1930, Mobergella versus Discinella; Paterella versus Scapha and Archaeophiala (some questions on nomenclature): Sveriges Geologiska Undersökning (C), v. 362, 8 p.Google Scholar
Jacob, D.E., Soldati, A.L., Wirth, R., Huth, J., Wehrmeister, U., and Hofmeister, W., 2008, Nanostructure, composition and mechanisms of bivalve shell growth: Geochimica et Cosmochimica Acta, v. 72, p. 5401–5415.CrossRefGoogle Scholar
Kefi, F.J., Lahbib, Y., Abdallah, L.G.B., and El Menif, N.T., 2012, Shell disturbances and butyltins burden in commercial bivalves collected from the Bizerta lagoon (northern Tunisia): Environmental Monitoring and Assessment, v. 184, p. 6869–6876.Google Scholar
Knight, I., 2013, The Forteau Formation, Labrador Group, in Gros Morne National Park: A preliminary reassessment of its stratigraphy and lithofacies: Current Research. Newfoundland and Labrador Department of Natural Resources, Geological Survey, Report, v. 13-1, p. 267–300.Google Scholar
Knight, I., and Boyce, W.D., 2015, Geological guide to the Bird Cove region, Great Northern Peninsula: Government of Newfoundland and Labrador, Department of Natural Resources, Geological Survey Open-File Report NFLD/3239.Google Scholar
Landing, E., and Bartowski, K.E., 1996, Oldest shelly fossils from the Taconic allochthon and late early Cambrian sea-levels in eastern Laurentia: Journal of Paleontology, v. 70, p. 741–761.Google Scholar
Landing, E., Geyer, G., and Bartowski, K.E., 2002, Latest early Cambrian small shelly fossils, trilobites, and Hatch Hill dysaerobic interval on the Québec continental slope: Journal of Paleontology, v. 76, p. 287–305.Google Scholar
Lochman, C., 1956, Stratigraphy, paleontology and paleogeography of the Elliptocephala asaphoides strata in Cambridge and Hoosick quadrangles, New York: Bulletin of the Geological Society of America, v. 67, p. 1331–1396.Google Scholar
Matthews, S.C., and Missarzhevsky, V.V., 1975, Small shelly fossils of late Precambrian and early Cambrian age: A review of recent work: Journal of the Geological Society, v. 131, p. 289–304.CrossRefGoogle Scholar
Missarzhevsky, V.V., 1989, Drevnejshie skeletnye okamenelosti i stratigrafiya pogranichnykh tolshch dokembriya i kembriya: Trudy Akademiya Nauk SSSR, v. 443, 238 p. (in Russian)Google Scholar
Moberg, J.C., 1892, Om en nyupptäckt fauna i block af kambrisk sandsten, insamlade av Dr. N.O. Holst: Geologiska Föreningens i Stockholm Förhandlingar, v. 14, p. 103–120.Google Scholar
Murdock, D.J., Donoghue, P.C.J., Bengtson, S., and Marone, F., 2012, Ontogeny and microstructure of the enigmatic Cambrian tommotiid Sunnaginia Missarzhevsky, 1969: Palaeontology, v. 55, p. 661–676.Google Scholar
Murdock, D.J., Bengtson, S., Marone, F., Greenwood, J.M., and Donoghue, P.C.J., 2014, Evaluating scenarios for the evolutionary assembly of the brachiopod body plan: Evolution & development, v. 16, p. 13–24.Google Scholar
Palmer, A.R., 1971, The Cambrian of the Appalachian and eastern New York regions, eastern United States, in Holand, C.H., ed. Cambrian of the New World: New York, Wiley-Interscience, p. 169–217.Google Scholar
Poulsen, C., 1932, The lower Cambrian faunas of East Greenland: Meddelelser om Grønland, v. 87, 66 p.Google Scholar
Rozanov, A.Y., and Zhuravlev, A.Y., 1992, The lower Cambrian fossil record of the Soviet Union, in Lipps, J.H., and Signor, P.H., eds., Origin and Early Evolution of the Metazoa: New York, Plenum Press, p. 205–282.Google Scholar
Schuchert, C., and Dunbar, C.O., 1934, Stratigraphy of western Newfoundland: Memoir of the Geological Society of America, v. 1, 123 p.Google Scholar
Skovsted, C.B., 2003, Mobergellans (Problematica) from the Cambrian of Greenland, Siberia and Kazakhstan: Paläontologische Zeitschrift, v. 77, p. 429–443.Google Scholar
Skovsted, C.B., 2006, Small shelly fauna from the late early Cambrian Bastion and Ella Island Formations, North-East Greenland: Journal of Paleontology, v. 80, p. 1087–1112.Google Scholar
Skovsted, C.B., and Peel, J.S., 2010, Early Cambrian brachiopods and other shelly fossils from the basal Kinzers Formation of Pennsylvania: Journal of Paleontology, v. 84, p. 754–762.Google Scholar
Skovsted, C.B., Brock, G.A., Paterson, J.R., Holmer, L.E., and Budd, G.E., 2008, The scleritome of Eccentrotheca from the lower Cambrian of South Australia: Lophophorate affinities and implications for tommotiid phylogeny: Geology, v. 36, p. 171–174.CrossRefGoogle Scholar
Skovsted, C.B, Holmer, L.E., Larsson, C.M., Högström, A.E.S., Brock, G.A., Topper, T.P., Balthasar, U., Petterson Stolk, S.P., and Paterson, J.R., 2009, The scleritome of Paterimitra: An early Cambrian stem group brachiopod from South Australia: Proceedings of the Royal Society B, v. 276, p. 1651–1656.Google Scholar
Skovsted, C.B., Brock, G.A., Topper, T.P., Paterson, J.R., and Holmer, L.E., 2011, Scleritome construction, biofacies, biostratigraphy and systematics of the tommotiid Eccentrotheca helenia sp. nov. from the early Cambrian of South Australia: Palaeontology, v. 54, p. 253–286.Google Scholar
Skovsted, C.B., Clausen, S., Álvaro, J.J., and Ponlevé, D., 2014, Tommotiids from the early Cambrian (Series 2, Stage 3) of Morocco and the evolution of the tannuolinid scleritome and setigerous shell structures in stem group brachiopods: Palaeontology, v. 57, p. 171–192.CrossRefGoogle Scholar
Skovsted, C.B., Knight, I., Balthasar, U., and Boyce, D., in press, Depth related brachiopod faunas from the lower Cambrian Forteau Formation of southern Labrador and western Newfoundland: Palaeontologica Electronica.Google Scholar
Spencer, L.M., 1980, Paleoecology of a lower Cambrian archaeocythid interreef fauna from southern Labrador [M.Sc. thesis]: New York, University of New York at Stony Brook, 163 p.Google Scholar
Streng, M, and Skovsted, C.B., 2006, A new mobergellan (small shelly fossils) from the early middle Cambrian of Morocco and its significance: Paläontologische Zeitschrift, v. 80, p. 209–220.Google Scholar
Topper, T.P., and Skovsted, C.B., 2017, Keeping a lid on it: Muscle scars and the mystery of the Mobergellidae: Zoological Journal of the Linnean Society, doi: 10.1093/zoolinnean/zlw011.Google Scholar
Walcott, C.D., 1886, Second contribution to the studies on the Cambrian faunas of North America: Bulletin of the United States Geological Survey, v. 30, 369 p.Google Scholar