The depositional environment and taphonomy of the Homerian “Aulacopleura shales” fossil assemblage near Loděnice, Czech Republic (Prague Basin, Perunican microcontinent)

 

Authors: Hughes NC, Kříž J, Macquaker JHS, Huff WD

Published in: Bulletin of Geosciences, volume 89, issue 2; pages: 219 - 238; Received 4 February 2013; Accepted in revised form 22 July 2013; Online 12 March 2014

Keywords: trilobite, cluster, Silurian, Barrande, ontogeny, olenimorph,

full text (PDF, 5.96 MB)

Export to RIS

 

Abstract

Excavation of Joachim Barrande’s classic fossil locality of the “Aulacopleura shales” exposed on Na Černidlech Hill, near Loděnice reveals that most specimens were recovered from a 1.4 m interval exposed in “Barrande’s pits”. These are located at the eastern end of a 0.4 km trench dug in the mid 1800’s to expose the interval along strike. Over an hundred bedding planes occur within the 1.4 m interval, and thousands of articulated trilobites have been collected at the site. Individual bed surfaces vary in the density, size, and taxonomic composition of the fossils contained. Some preserve a diverse benthic shelly fauna, others are almost exclusively dominated by the trilobite Aulacopleura koninckii, and a third variety is apparently barren of all shelly fossils. Isolated sclerites of A. koninckii are rare, and on almost all bedding surfaces exoskeletons are predominantly partially articulated and lack both alignment and sclerite fragmentation. The occurrence of A. koninckii conforms in many ways to the characteristics of a Type I trilobite lagerstatte of Brett et al. (2012). The presence of enrolled A. koninckii suggests that final burial may have resulted from relatively rapid obrution, although the condition of partial articulation indicates that many carcasses or exuviae partially disaggregated before burial. The mean size and density of A. koninckii specimens varies markedly among bedding planes, with some assemblages entirely comprised of juveniles, suggesting that notably dense trilobite clustering was not restricted only to reproductively mature individuals. The presence of multiple clusters of different mean specimen size partly accounts from the unusually comprehensive record of the articulated meraspid and holaspid ontogeny of this species at this locality. Limited bioturbation suggests a dysoxic substrate, and the olenimorphic form and distribution of A. koninckii, combined with a lack of encrustation or predation upon it, suggests that this species may have periodically bloomed in abundance at particular oxygen concentrations that largely excluded other skeletonized benthos. Some bedding plane assemblages might represent mass mortality events, perhaps as available oxygen passed below levels necessary to maintain the metabolism of A. koninckii.

References

ALLISON, P.A., WIGNALL, P.B. & BRETT, C.E. 1995. Palaeo-oxygenation: effects and recognition, 97-112. In BOSENCE, D.W.J. & ALLISON, P.A. (eds) Marine Palaeoenvironmental Analysis from Fossils. Geological Society of London, Special Publication 83.

BARRANDE, J. 1846. Notice préliminaire sur le systeme silurien et les trilobites de Boheme. 97 pp. Hirschfeld, Leipzig.

BARRANDE, J. 1852. Systeme silurien du centre de la Boheme. Iere partie. Recherches paléontologiques. 935 pp. Privately published, Prague & Paris. View article

BOUČEK, B. 1941. Über einem neuen Aufschluss im Silur bei Lodenitz. Zprávy Geologického ústavu pro Čechy a Moravu 17, 165-172.

BRANDT, D.S. 2002. Ecdysial efficiency and evolutionary efficacy among marine arthropods: implications for trilobite survivorship. Alcheringa 26, 399-421.View article

BRETT, C.E. & BAIRD, G.C. 1993. Taphonomic approaches to temporal resolution in stratigraphy: examples from Paleozoic marine mudrocks, 250-274. In KIDWELL, S.M. & BEHRENSMEYER, A.K. (eds) Taphonomic approaches to time resolution in the fossil record. Paleontological Society, Knoxville, Tennessee.

BRETT, C.E., BAIRD, G.C. & SPEYER, S.E. 1997. Fossil Lagerstätte: Stratigraphic record of paleontological and taphonomic events, 3-40. In BRETT, C.E. & BAIRD, G.C. (eds) Paleontological events, stratigraphic, ecological and evolutionary implications. Columbia University Press, New York.

BRETT, C.E., ZAMBITO, J.J., HUNDA, B.R. & SCHINDLER, E. 2012. Mid-Paleozoic trilobite lagerstatten: models of diagenetically enhanced obrution deposits. Palaios 27, 326-345.View article

BRIGHT, R.C. 1959. A paleoecologic and biometric study of the Middle Cambrian trilobite Elrathia kingii (Meek). Journal of Paleontology 33, 83-98.

CHATTERTON, B.D.E. & LUDVIGSEN, R. 1998. Upper Steptoean (Upper Cambrian) trilobites from the McKay Group of southeastern British Columbia, Canada. Journal of Paleontology, The Paleontological Society Memoir 72 (supplement to No. 2), 1-43.

CHLUPÁČ, I. 1983. Trilobite assemblages in the Devonian of the Barrandian area and their relations to palaeoenvironments. Geologica et Palaeontologica 17, 45-73.

COCKS, L.R.M. & TORSVIK, T.H. 2002. Earth geography from 500 to 400 million years ago: a faunal and palaeomagnetic review. Journal of the Geological Society 159, 631-644.View article

CRAMER, B.D. & SALTZMAN, M.R. 2007. Fluctuations in eperic sea carbonate production during Silurian positive carbon isotope excursions: a review of proposed paleooceanographic models. Palaeogeography, Palaeoclimatology, Palaeoecology 245, 37-45.View article

CRÔNIER, C., BARTZSCH, K., WEYER, D. & FEIST, R. 1999. Larval morphology and ontogeny of a late Devonian phacopid with reduced sight from Thuringia, Germany. Journal of Paleontology 73, 240-255. View article

DROSER, M.L. & BOTTJER, D.J. 1986. A semiquantitative field classification of ichnofabric. Journal of Sedimentary Petrology 56, 558-589.View article

FARRELL, U.C., BRIGGS, D.E.G. & GAINES, R.R. 2011. Paleoecology of the olenid trilobite Triarthrus: new evidence from Beecher’s trilobite bed and other sites of pyritization. Palaios 26, 730-742.View article

FORTEY, R.A. 2000. Olenid trilobites: The oldest known chemoautotrophic symbionts? Proceedings of the National Academy of Sciences of the United States of America 97, 6574-6578.View article

FORTEY, R.A. & OWENS, R.M. 1990. Trilobites, 121-142. In McNAMARA, K.J. (ed.) Evolutionary Trends. Belhaven Press, London.

FORTEY, R.A. & OWENS, R.M. 1999. Feeding habits in trilobites. Palaeontology 42, 429-465.View article

FUSCO, G., HUGHES, N.C., WEBSTER, M. & MINELLI, A. 2004. Exploring developmental modes in a fossil arthropod: growth and trunk segmentation of the trilobite Aulacopleura konincki. American Naturalist 163, 167-183.View article

FUSCO, G., HONG, P.S. & HUGHES, N.C. 2014. Positional specification in the segmental growth pattern of an early arthropod. Proceedings of the Royal Society of London, Series B 281, 20133037.View article

GAINES, R.R. & DROSER, M.L. 2003. Paleoecology of the familiar trilobite Elrathia kingii: an early exaerobic zone inhabitant. Geology 31, 941-944.View article

GUPTA, V.J. & SHAW, F.C. 1985. Lower Palaeozoic trilobites from Zanskar Valley, Ladakh, Himalaya, India. Research Bulletin (Science) of the Panjab University 36, 335-344.

GUTIÉRREZ-MARCO, J.C., SÁ, A.A., GARCÍA-BELLIDO, D.C., RÁBANO, I. & VALÉRIO, M. 2009. Giant trilobites and trilobite clusters from the Ordovician of Portugal. Geology 37, 443-446.View article

HAVLÍČEK, V., VANĚK, J. & FATKA, O. 1994. Perunica microcontinent in the Ordovician (its position within the Mediterranean Province, series division, benthic and pelagic associations). Sborník geologických věd, Geologie 46, 23-56.

HENNINGSMOEN, G. 1975. Moulting in trilobites. Fossils and Strata 4, 179-200.

HONG, P.S., HUGHES, N.C. & SHEETS, H.D.S. in press. Size, shape and systematics of Silurian trilobite Aulacopleura koninckii. Journal of Paleontology.

HORNÝ, R. 1955. The Budnany Beds in the western part of the Silurian of the Barrandian. Sborník Ústředního ústavu geologického, Oddíl geologický 21, 315-409.

HORNÝ, R. 1965. Tectonic structure and development of the Silurian between Beroun and Tachlovice. Časopis pro mineralogii a geologii 10, 147-155.

HUFF, W.D., BERGSTRÖM, S.M. & KOLATA, D.R. 1992. Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance. Geology 20, 875-878.View article

HUGHES, N.C. 1999. Statistical and imaging methods applied to deformed fossils, 127-155. In HARPER, D.A.T. (ed.) Numerical Palaeobiology. John Wiley, London.

HUGHES, N.C. & CHAPMAN, R.E. 1995. Growth and variation in the Silurian proetide trilobite Aulacopleura konincki and its implications for trilobite palaeobiology. Lethaia 28, 333-353.View article

HUGHES, N.C., CHAPMAN, R.E. & ADRAIN, J.M. 1999. The stability of thoracic segmentation in trilobites: a case study in developmental and ecological constraints. Evolution and Development 1, 24-35.View article

HUGHES, N.C. & COOPER, D.L. 1999. Paleobiologic and taphonomic aspects of the “granulosa” trilobite assemblage, Kope Formation (Upper Ordovician, Cincinnati region). Journal of Paleontology 73, 306-319. View article

HUGHES, N.C., MINELLI, A. & FUSCO, G. 2006. The ontogeny of trilobite segmentation: a comparative approach. Paleobiology 32, 602-627.View article

HUNDA, B.R., HUGHES, N.C. & FLESSA, K.W. 2006. Trilobite taphonomy and temporal resolution in the Mt. Orab Shale Bed (Upper Ordovician, Ohio, USA). Palaios 21, 26-45.View article

KARIM, T. & WESTROP, S.R. 2002. Taphonomy and paleoecology of Ordovician trilobite clusters, Bromide Formation, south-central Oklahoma. Palaios 17, 394-402.View article

KOHRS, R., BRETT, C.E. & O’BRIEN, N. 2008. Sedimentology of Upper Ordovician mudstones from the Cincinnati Arch region, Ohio/Kentucky: toward a general model of mud event deposition, 88-111. In MCLAUGHLIN, P.I., BRETT, C.E. HOLLAND, S.M. & STORRS, G. (eds) Stratigraphic renaissance in the Cincinnati Arch: Implications for Upper Ordovician paleontology and paleoecology. Cincinnati Museum Center, Cincinnati, OH.

KŘÍŽ, J. 1962. Nové nálezy druhu Phaetonellus dentatulus (Novák, 1890)/Neue Funde der Art Phaetonellus dentatulus (Novák, 1890) - Barrandes Lokalität Lodenice. Časopis pro mineralogii a geologii 7, 139-144.

KŘÍŽ, J. 1991. The Silurian of the Prague Basin (Bohemia) - tectonic, eustatic and volcanic controls on facies and faunal development, 179-203. In BASSETT, M.G., LANE, P.D. & EDWARDS, D. (eds) The Murchison Symposium: proceedings of an international conference on the Silurian System. Special Papers in Palaeontology.

KŘÍŽ, J. 1992. Silurian Field Excursions: Prague Basin (Barrandian), Bohemia. National Museum of Wales, Geological Series 13, 1-111.

KŘÍŽ, J. 2007. Origin, evolution and classification of the new superorder Nepiomorphia (Mollusca, Bivalvia, Lower Paleozoic). Palaeontology 50, 1341-1365.View article

KŘÍŽ, J., DEGARDIN, J.-M., FERRETTI, A., HANSCH, W., GUTIÉRREZ-MARCO, J.C., PARIS, F., PIÇARRA D’ALMEIDA, J.M., ROBARDET, M., SCHÖNLAUB, H.-P. & SERPAGLI, E. 2003. Silurian stratigraphy and paleogeography of north Gondwanan and Perunican Europe, 105-178. In LANDING, E. & JOHNSON, M.E. (eds) Silurian lands and seas - paleogeography outside of Laurentia. New York State Museum Bulletin.

KŘÍŽ, J., DUFKA, P., JAEGER, H. & SCHÖNLAUB, H.P. 1993. The Wenlock/Ludlow boundary in the Prague Basin (Bohemia). Jahrbuch der Geologischen Bundesanstalt A 136, 809-839.

LIN, J.-P. & YUAN, J.-L. 2009. Reassessment of the mode of life of Pagetia Walcott, 1916 (Trilobita: Eosdiscidae) based on a cluster of intact exuviae from the Kaili Formation (Cambrian) of Guizhou, China. Lethaia 42, 67-73.View article

LOYDELL, D.K. 2012. Graptolite biozone correlation charts. Geological Magazine 149, 124-132.View article

MANDA, Š. 2008. Palaeoecology and palaeogeographic relations of the Silurian phragmoceratids (Nautiloidea, Cephalopoda) of the Prague Basin (Bohemia). Bulletin of Geosciences 83, 39-62.View article

MELCHIN, M.J., SADLER, P.M. & CRAMER, B.D. 2012. The Silurian Period, 525-558. In GRADSTEIN, F.M., OGG, J.G., SCHMITZ, M. & OGG, G.M. (eds) The Geologic Time Scale 2012. Elsevier, Amsterdam.

NOVÁK, O.P. 1890. Vergleichende Studien an einingen Trilobiten aus den Herzyn von Bicken, Wildungen, Greifenstein und Böhmen. Paläontologische Abhandlungen, Neue Folge 1, 95-138.

PATERSON, J.R., JAGO, J.B., BROCK, G.A. & GEHLING, J.G. 2007. Taphonomy and palaeoecology of the emuellid trilobite Balcoracania dailyi (early Cambrian, South Australia). Palaeogeography, Palaeoclimatology, Palaeoecology 249, 302-321.View article

SADLER, P.M. 1981. Sediment accumulation rates and the completeness of stratigraphic sections. Journal of Geology 89, 565-584.View article

SAVRDA, C.E. & BOTTJER, D.J. 1987. The exaerobic zone, a new oxygen-deficient marine biofacies. Nature 327, 54-56.View article

SEKIGUCHI, K. 1988. Biology of Horseshoe Crabs. 428 pp. Tokyo, Science House.

SPEYER, S.E. 1987. Comparative taphonomy and paleoecology of trilobite lagerstätten. Alcheringa 11, 205-232.View article

SPEYER, S.E. & BRETT, C.E. 1985. Clustered trilobite assemblages in the Middle Devonian Hamilton Group. Lethaia 18, 85-103.View article

SUZUKI, Y. & BERGSTRÖM, J. 2008. Respiration in trilobites. Geologiska Föreningens i Stockholm Förhandlingar 130, 211-229.

TALENT, J.A, BROCK, G.A., ENGELBRETSEN, M.A., GAETANI, M., JELL, P.A., MAWSON, R., TALENT, R.C. & WEBSTER, G.D. 1990. Himalayan palaeontologic database polluted: Plagiarism and other anomalies. Journal of the Geological Society of India 35, 569-585.

THOMAS, A.T. & LANE, P.D. 1984. Autecology of Silurian trilobites. Special Papers in Palaeontology 32, 55-69.

VANĚK, J. 1966. Studie o trilobitové fauně „aulakopleurových břidlic“ na lokalitě Černidla u Loděnice. Zprávy o geologických výzkumech v roce 1965, 113-114.

VANĚK, J. 1990. Exact age of several localities in the Liteň Formation, Motol Member (Wenlock, Central Bohemia). Věstník Ústředního ústavu geologického 65, 119-124.

VERNIERS, J., MALETZ, J., KŘÍŽ, J., ŽIGAITÉ, Ž., PARIS, F., SCHÖNLAUB, H.-P. & WRONA, R. 2008. Silurian, 249-302. In MCCANN, T. (ed.) The Geology of Central Europe, Volume 1: Precambrian and Palaeozoic. The Geological Society, London.

WEBSTER, M., GAINES, R.R. & HUGHES, N.C. 2008. Microstratigraphy, trilobite biostratinomy, and depositional environment of the “lower Cambrian” Ruin Wash lagerstätte, Pioche Formation, Nevada. Palaeogeography, Palaeoclimatology, Palaeoecology 284, 100-122.View article

WHITTINGTON, H.B. 1986. Late middle Cambrian trilobites from Zanskar, Ladakh, northern India. Rivista Italiana di Paleontologia e Stratigrafia 92, 171-188.