Hostname: page-component-7479d7b7d-k7p5g Total loading time: 0 Render date: 2024-07-13T02:23:24.401Z Has data issue: false hasContentIssue false

Evolutionary roots of the conodonts with increased number of elements in the apparatus

Published online by Cambridge University Press:  09 December 2015

Jerzy Dzik*
Affiliation:
Instytut Paleobiologii PAN, Twarda 51/55, 00-818 Warszawa, Poland. Wydział Biologii Uniwersytetu Warszawskiego, Aleja Żwirki i Wigury 101, Warszawa 02-096, Poland. Email: dzik@twarda.pan.pl

Abstract

Four kinds of robust elements have been recognised in Amorphognathus quinquiradiatus Moskalenko, 1977 (in Kanygin et al. 1977) from the early Late Ordovician of Siberia, indicating that at least 17 elements were present in the apparatus, one of them similar to the P1 element of the Early Silurian Distomodus. The new generic name Moskalenkodus is proposed for these conodonts with a pterospathodontid-like S series element morphology. This implies that the related Distomodus, Pterospathodus and Gamachignathus lineages had a long cryptic evolutionary history, probably ranging back to the early Ordovician, when they split from the lineage of Icriodella, having a duplicated M location in common. The balognathid Promissum, with a 19-element apparatus, may have shared ancestry with Icriodella in Ordovician high latitudes, with Sagittodontina, Lenodus, Trapezognathus and Phragmodus as possible connecting links. The pattern of the unbalanced contribution of Baltoniodus element types to samples suggests that duplication of M and P2 series elements may have been an early event in the evolution of balognathids. The proposed scenario implies a profound transformation of the mouth region in the evolution of conodonts. The probable original state was a chaetognath-like arrangement of coniform elements; all paired and of relatively uniform morphology. This was modified at the origin of protopanderodontids by the introduction of a medial S0 element, which resulted in the separation of the exposed unit of M and S series elements from the P series elements hidden in the throat. A rotation of the S series elements to an almost horizontal position in early prioniodontids may have promoted duplication of the M element pair. In Gamachignathus, Icriodella and Pterospathodus lineages, these elements are differentiated morphologically. Subsequent anteriorward bending of the P element series caused duplication of the balognathid P2 element pair, but they remained undifferentiated, even in the otherwise elaborate Promissum. The whole clade of conodonts with supernumerary element pairs in the apparatus has its roots in high latitudes of the Ordovician.

Type
Articles
Copyright
Copyright © The Royal Society of Edinburgh 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

11. References

Albanesi, G. L. & Barnes, C. R. 2000. Subspeciation within a punctuated equilibrium evolutionary event: phylogenetic history of the Lower–Middle Ordovician Paroistodus originalis–P. horridus complex (Conodonta). Journal of Paleontology 74, 492502.Google Scholar
Aldridge, R. J. 1972. Llandovery conodonts from the Welsh Borderland. Bulletin of the British Museum Natural History (Geology) 22, 125231.Google Scholar
Aldridge, R. J. 1982. A fused cluster of coniform elements from the late Ordovician of Washington Land, western North Greenland. Palaeontology 25, 425–30.Google Scholar
Aldridge, R. J., Smith, M. P., Norby, R. D. & Briggs, D. E. G. 1987. The architecture and function of Carboniferous polygnathacean conodont apparatuses. In Aldridge, R. A. (ed.) Palaeobiology of Conodonts, 7790. British Micropalaeontological Society Special Publication. Chichester, UK: Ellis Horwood. 180 pp.Google Scholar
Aldridge, R. J., Purnell, M. A., Gabbott, S. E. & Theron, J. N. 1995. The apparatus architecture and function of Promissum pulchrum Kovács-Endrödy (Conodonta, Upper Ordovician) and the prioniodontid plan. Philosophical Transactions of the Royal Society, London 347B, 275–91.Google Scholar
Aldridge, R. J., Murdock, D. J. E., Gabbott, S. E. & Theron, J. N. 2013. A 17-element conodont apparatus from the Soom Shale Lagerstätte (Upper Ordovician), South Africa. Palaeontology 56, 261–76.Google Scholar
An, Tai-xiang. 1987. The Lower Paleozoic Conodonts of South China. Beijing: Peking University Press. 238 pp.Google Scholar
Andres, D. 1988. Strukturen, Apparate und Phylogenie primitiver Conodonten. Palaeontographica 200A, 105–52.Google Scholar
Armstrong, H. A. 1990. Conodonts from the Upper Ordovician–lower Silurian carbonate platform of North Greenland. Grønlands Geologiske Undersøgelse 159, 1151.Google Scholar
Armstrong, H. A. 1996. Biotic recovery after mass extinction: the role of climate and ocean-state in the post-glacial (Late Ordovician–Early Silurian) recovery of the conodonts. In Hart, M. B. (ed.) Biotic Recovery from Mass Extinction Events. Geological Society, London, Special Publication 102, 105–17. London & Bath: The Geological Society Publishing House. 392 pp.Google Scholar
Armstrong, H. A., Johmson, E. W. & Scott, R. W. 1996. Conodont biostratigraphy of the attenuated Dent Group (upper Ordovician) at Hartley Ground, Broughton in Furness, Cumbria, UK. Proceedings of the Yorkshire Geological Society 51, 921.Google Scholar
Bader, J. D. 2007. Telychian (Llandovery, Silurian) conodonts from the Chimneyhill Subgroup, West Carney Hunton Field, Northcentral Oklahoma. MSc Thesis, Texas Tech University. 84 pp.Google Scholar
Bagnoli, G. & Stouge, S. 1997. Lower Ordovician (Billingenian–Kundan) conodont zonation and provinces based on sections from Horns Udde, north Öland, Sweden. Bolletino della Societa Paleontologica Italiana 35, 109–63.Google Scholar
Bergström, S. M. 1971. Conodont biostratigraphy of the Middle and Upper Ordovician of Europe and eastern North America. Geological Society of America, Memoir 127, 83161.Google Scholar
Bergström, S. M. 1983. Biogeography, evolutionary relationships, and biostratigraphic significance of Ordovician platform conodonts. Fossils and Strata 15, 3558.Google Scholar
Bergström, S. & Bergström, J. 1996. The Ordovician–Silurian boundary succession in Östergötland and Västergötland, S. Sweden. Geologiska Föreningens i Stockholm Förhandlingar 118, 2542.Google Scholar
Bischoff, G. C. O. 1986. Early and middle Silurian conodonts from midwestern New SouthWales. Courier Forschungsinstitut Senckenberg 89, 1337.Google Scholar
Bischoff, G. C. O. 1997. Ansella mischa n. sp. (Conodonta) from late Llandoverian and early Wenlockisn strata of Midwestern Now South Wales. Neues Jahrbuch für Geologie und Paläontologie Monatshefte 1997, 477–88.Google Scholar
Boogaardvan den, M. van den, M. & Kuhry, B. 1979. Statistical reconstruction of the Palmatolepis apparatus (Late Devonian conodontophorids) at the generic, subgeneric, and specific level. Scripta Geologica 49, 157.Google Scholar
Branson, E. B. & Branson, C. C. 1947. Lower Silurian conodonts from Kentucky. Journal of Paleontology 21, 549–56.Google Scholar
Branson, E. B. & Mehl, M. G. 1933. Conodont studies. 1–4. University of Missouri Studies 8, 1349.Google Scholar
Brenchley, P. J., Romano, M., Young, T. P. & Storch, P. 1991. Hirnantian glaciomarine diamictites – evidence for the spread of glaciations and its effects on Ordovician faunas. Geological Survey of Canada Paper 90, 325–36.Google Scholar
Brenchley, P. J., Marshall, J. D. & Underwood, C. J. 2001. Do all mass extinctions represent an ecological crisis? Evidence from the Late Ordovician. Geological Journal 36, 329–40.Google Scholar
Carlorosi, J. M. T. & Heredia, S. E. 2013. The Ordovician conodont Trapezognathus Lindström, 1955 in the Andean Basin, Argentina. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 267, 309–21.Google Scholar
Chen, X, Bergström, S. M., Zhang, Y., Goldman, D. & Chen, Q. 2010. Upper Ordovician (Sandbian–Katian) graptolite and conodont zonation in the Yangtze region, China. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101, 111–34.Google Scholar
Chen, M. -J. & Zhang, L. -H. 1984. Middle Ordovician conodonts from Tangshan, Nanjing. Acta Micropalaeontologica Sinica 1, 120–37.Google Scholar
Clark, D. L., Sweet, W. C., Bergström, S. M., Klapper, G., Austin, R. L., Rhodes, H. T., Mülle, K. L., Ziegler, W., Lindström, M., Miller, J. F. & Harris, A. G. 1981. Treatise on Invertebrate Paleontology, Conodonta. Part W, Supplement 2. Boulder, Colorado & Lawrence, Kansas: Geological Society of America and University of Kansas Press. 202 pp.Google Scholar
Donoghue, P. C. J, Purnell, M. A. Aldridge, R. J. & Zhang, S. 2008. The interrelationships of ‘complex’ conodonts (Vertebrata). Journal of Systematic Palaeontology 6, 119–53.Google Scholar
Drygant, D. M. 1974. New Middle Ordovician Conodonts from the northwestern Volhynia. Paleontologichesky sbornik 11, 5458.Google Scholar
Dzik, J. 1976. Remarks on the evolution of Ordovician conodonts. Acta Palaeontologica Polonica 21, 395455.Google Scholar
Dzik, J. 1978. Conodont biostratigraphy and paleogeographical relations of the Ordovician Mójcza Limestone (Holy Cross Mts., Poland). Acta Palaeontologica Polonica 23, 5172.Google Scholar
Dzik, J. 1980. Isolated mandibles of early Palaeozoic phyllocarid Crustacea. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 1980(2), 87106.Google Scholar
Dzik, J. 1984. Early Ordovician conodonts from the Barrandian and Bohemian–Baltic faunal relationships. Acta Palaeontologica Polonica 28, 327–68.Google Scholar
Dzik, J. 1990. Conodont evolution in high latitudes of the Ordovician. Courier Forschungsinstitut Senckenberg 117, 128.Google Scholar
Dzik, J. 1994. Conodonts of the Mójcza Limestone. Palaeontologia Polonica 53, 43128.Google Scholar
Dzik, J. 1996. Dzieje życia na Ziemi. Wprowadzenie do paleobiologii. Wydanie 2, zmienione i poprawione. Warszawa: Państwowe Wydawnictwo Naukowe. 515 pp.Google Scholar
Dzik, J. 1999. Relationship between rates of speciation and phyletic evolution: Stratophenetic data on pelagic conodont chordates and benthic ostracods. Geobios 32, 205–21.Google Scholar
Dzik, J. 2000. The origin of the mineral skeleton in chordates. Evolutionary Biology 31, 105–54.Google Scholar
Dzik, J. 2005. The chronophyletic approach: stratophenetics facing an incomplete fossil record. Special Papers in Palaeontology 73, 159–83.Google Scholar
Dzik, J. 2006. The Famennian “Golden Age” of conodonts and ammonoids in the Polish part of the Variscan Sea. Palaeontologia Polonica 63, 1359.Google Scholar
Dzik, J. 2008. Evolution of morphogenesis in 360-million-year-old conodont chordates calibrated in days. Evolution & Development 10, 769–77.Google Scholar
Dzik, J. 2010. Brachiopod identity of the alleged Late Cambrian monoplacophoran ancestors of cephalopods. Malacologia 52, 97113.Google Scholar
Dzik, J. & Drygant, D. 1986. The apparatus of panderodontid conodonts. Lethaia 19, 133–41.Google Scholar
Dzik, J. & Pisera, A. 1994. The Mójcza Limestone and its sedimentation. Palaeontologia Polonica 53, 541.Google Scholar
Eichenberg, W. 1930. Conodonten aus dem Culm des Harzes. Paläontologische Zeitschrift 12, 177–82.Google Scholar
Fåhraeus, L. E. 1966. Lower Viruan (Middle Ordovician) conodonts from the Gullhögen Quarry, southern-central Sweden. Sveriges Geologiska Undersökning, Series C 610, 140.Google Scholar
Ferretti, A. & Barnes, C. R. 1997. Upper Ordovician conodonts from the Kalkbank limestone of Thuringia, Germany. Palaeontology 40, 1542.Google Scholar
Ford, J. A. 1962. A Quantitative Method for Deriving Cultural Chronology. Revised version of the working paper prepared for the Teaching Seminar in the Methods of Establishing Chronological Sequences of Pre-Columbian Cultures in the Americas, Barranquilla, Colombia, June 25-July 6, 1961 (Technical Manual 1). Washington, D. C.: Pan American Union. 118 pp.Google Scholar
Gutiérrez-Marco, J. C., Albanesi, G. L., Sarmiento, G. N. & Carlotto, V. 2008. An Early Ordovician (Floian) Conodont Fauna from the Eastern Cordillera of Peru (Central Andean Basin). Geologica Acta 6, 147–60.Google Scholar
Hints, L., Hints, O., Kaljo, D., Kiipli, T. Männik, P., Nõlvak, J. & Pärnaste, H. 2010. Hirnantian (latest Ordovician) bio- and chemostratigraphy of the Stirnas-18 core, western Latvia. Estonian Journal of Earth Science 59, 124.Google Scholar
Kaljo, H. D., Hints, L., Männik, P. & Nõlvak, J. 2008. The succession of Hirnantian events based on data from Baltica: brachiopods, chitinozoans, conodonts and carbon isotopes. Estonian Journal of Earth Science 57, 197218.Google Scholar
Kanygin, A. V., Moskalenko, T. A., Yadrenkina, A. G. & Semenova, V. S. 1977. O stratigraficheskom raschlenenii i korrelacii srednego ordovika Sibirskoi Platformy. Trudy Instituta Geologii i Geofiziki SOAN SSSR 372, 343.Google Scholar
Kanygin, A. V., Moskalenko, T. A., Divina, T. A., Matukhina, V. G. & Yadrenkina, A. G. 1984. Ordovik zapadnoi chasti Irkutskogo amfiteatra. Trudy Instituta Geologii i Geofiziki SOAN SSSR 529, 3156.Google Scholar
Kanygin, A. V., Moskalenko, T. A., Yadrenkina, A. G., Abaimova, V. S., Sychev, O. V. & Timokhin, A. V. 1989. Ordovik Sibirskoi Platformy. Fauna i stratigrafia Lenskoy facialnoi oblasti. Trudy Instituta Geologii i Geofiziki SOAN SSSR 751, 3215.Google Scholar
Kanygin, A. V., Dronov, A., Timokhin, A. & Gonta, T. 2010a. Depositional sequences and palaeoceanographic change in the Ordovician of the Siberian craton. Palaeogeography, Palaeoclimatology, Palaeoecology 296, 285–96.Google Scholar
Kanygin, A. V., Koren, T. N., Yadrenkina, A. G., Timokhin, A. V., Sychev, O. V. & Tolmacheva, Y. Yu. 2010b. Ordovician of the Siberian Platform. In Finney, S. C. & Berry, W. B. N. (eds) The Ordovician Earth System. Geological Society of America, Special Paper 466, 105–17. Boulder, Colorado: The Geological Society of America. 200 pp.Google Scholar
Kleisner, K. 2007. The formation of the theory of homology in biological sciences. Acta Biotheoretica 55, 317–40.Google Scholar
Knüpfer, J. 1967. Zur Fauna und Biostratigraphie des Ordoviziums (Gräfenthaler Schichten) in Thüringen. Freiberger Forschungshefte C220, 1119.Google Scholar
Lange, F. -G. 1968. Conodonten-Gruppenfunde aus Kalken des tieferen Oberdevon. Geologica et Palaeontologica 2, 3757.Google Scholar
Leslie, S. A. & Bergström, S. M. 1995. Element morphology and taxonomic relationships of the Ordovician conodonts Phragmodus primus Branson and Mehl, 1933, the type species of Phragmodus Branson and Mehl, 1933, and Phragmodus undatus Branson and Mehl, 1933. Journal of Paleontology 69, 967–74.Google Scholar
Leslie, S. A. & Lehnert, O. 1999. New insight into the phylogeny and paleogeography of Cahabagnathus (Conodonts). Acta Universitatis Carolinae, Geologica 43, 443–46.Google Scholar
Leslie, S. A. & Lehnert, O. 2005. The evolution of the Ordovician conodont genus Cahabagnathus Bergström, 1983. Journal of Palaeontology 79, 1131–42.Google Scholar
Lindström, M. 1955. Conodonts from the lowermost Ordovician strata of south-central Sweden. Geologiska Föreningens i Stockholm Förhandlingar 76, 517604.Google Scholar
Lindström, M., Racheboeuf, P. R. & Henry, J.-P. 1974. Ordovician conodonts from the Postolonnec Formation (Crozon peninsula, Massif Armoricain) and their stratigraphic significance. Geologica et Palaeontologica 8, 1528.Google Scholar
Löfgren, A. 1997. Conodont faunas from the upper Tremadoc at Brattefors, south-central Sweden and reconstruction of the Paltodus apparatus. Geologiska Föreningens i Stockholm Förhandlingar 119, 257–66.Google Scholar
Löfgren, A. 1990. Non-platform elements of the Ordovician conodont genus Polonodus. Paläontologische Zeitschrift 64, 245–59.Google Scholar
Löfgren, A. & Tolmacheva, T. 2008. Morphology, evolution and stratigraphic distribution in the Middle Ordovician conodont genus Microzarkodina. Earth and Enviromental Sciences Transactions of the Royal Society of Edinburgh 99, 2748.Google Scholar
Männik, P. 1992. A new conodont from the Lower Llandovery of Estonia. Proceedings of the Estonian Academy of Sciences, Geology 41, 2338.Google Scholar
Männik, P. 1998. Evolution and taxonomy of the Silurian conodont Pterospathodus. Palaeontology 41, 1001–50.Google Scholar
Männik, P. 2007. Recent developments in the Upper Ordovician and lower Silurian conodont biostratigraphy in Estonia. Estonian Journal of Earth Sciences 56, 3546.Google Scholar
Männik, P. & Aldridge, R. J. 1989. Evolution, taxonomy, and relationships of the Silurian conodont Pterospathodus. Palaeontology 32, 893906.Google Scholar
Männik, P. & Viira, V. 2012. Ordovician conodont diversity in the northern Baltic. Estonian Journal of Earth Sciences 61, 114.Google Scholar
Marsal, D. & Lindström, M. 1972. A contribution to the taxonomy of conodonts: The statistical reconstruction of fragmented populations. Geologica et Palaeontologica SB 1, 4346.Google Scholar
McCracken, A. D. 1989. Protopanderodus (Conodontata) from the Ordovician Road River Group, northern Yukon Territory, and the evolution of the genus. Geological Survey of Canada Bulletin 388, 139.Google Scholar
McCracken, A. D. 1991. Silurian conodont biostratigraphy of the Canadian Cordillera with a description of new Llandovery species. Geological Survey of Canada, Bulletin 417, 97127.Google Scholar
McCracken, A. D., Nowlan, G. S. & Barnes, C. R. 1980, Gamachignathus, a new multi-element conodont genus from the latest Ordovician, Anticosti Island, Quebec. Current Research C, Geological Survey of Canada, Paper 80-1C, 103–12.Google Scholar
McCracken, A. D. & Barnes, C. R. 1981. Conodont biostratigraphy and paleoecology of the Ellis Bay Formation, Anticosti Island, Quebec, with special reference to Late Ordovician–Early Silurian chronostratigraphy and the systemic boundary. Geological Society of Canada Bulletin 329, 51134.Google Scholar
McGoff, H. J. 1991. The hydrodynamics of conodont elements. Lethaia 24, 235–47.Google Scholar
Melchin, M. J., McCracken, A. D. & Oliff, F. J. 1991. The Ordovician–Silurian boundary on Cornwallis and Truro Islands, Arctic Canada: preliminary data. Canadian Journal of Earth Sciences 28, 1854–62.Google Scholar
Mestre, A. & Heredia, S. 2013. Biostratigraphic significance of Darriwilian conodonts from Sierra de LaTrampa (Central Precordillera, San Juan, Argentina). Geosciences Journal 17, 4353.Google Scholar
Miller, C. G. & Aldridge, R. J. 1993. The taxonomy and apparatus structure of the Silurian distomodontid conodont Coryssognathus Link & Druce, 1972. Journal of Micropalaeontology 12, 241–25.Google Scholar
Moskalenko, T. A. 1970. Konodonty krivolutskogo yarusa (sredniy ordovik) Sibirskoy platformy. Trudy Instituta Geologii i Geofiziki SOAN SSSR 61, 3115.Google Scholar
Moskalenko, T. A. 1973. Konodonty srednego i verkhnego ordovika Sibirskoi platformy. Trudy Instituta Geologii i Geofiziki SOAN SSSR 137, 3143.Google Scholar
Moskalenko, T. A. 1983. Conodonts and biostratigraphy in the Ordovician of the Siberian Platform. Fossils and Strata 15, 8794.Google Scholar
Mostler, H. 1967. Conodonten aus dem tieferen Silur der Kitzbuhler Alpen (Tirol). Annalen des Naturhistorischen Museums in Wien 71, 295303.Google Scholar
Nicoll, R. S. 1982. Multielement composition of the conodont Icriodus expansus Branson & Mehl from the Upper Devonian of the Canning Basin, Western Australia. Bureau of Mineral Resources, Journal of Australian Geology and Geophysics 7, 197213.Google Scholar
O'Brien, M. J. & Lyman, R. L. 1998. James A. Ford and the Growth of Americanist Archaeology. Columbia, Missouri: University of Missouri Press. 377 pp.Google Scholar
Orchard, M. J. 1980. Upper Ordovician conodonts from England and Wales. Geologica et Palaeontologica 14, 944.Google Scholar
Purnell, M. A. 2003. Casting, replication, and anaglyph stereo imaging of microscopic detail in fossils, with examples from conodonts and other jawless vertebrates. Palaeontologia Electronica 6(2), 111. http://palaeo-electronica.org/paleo/2003_2/rubber/issue2_03.htmGoogle Scholar
Purnell, M. A., Donoghue, P. C. J. & Aldridge, R. J. 2000. Orientation and anatomical notation in conodonts. Journal of Paleontology 74, 113–22.Google Scholar
Purnell, M. A. & Donoghue, P. C. J. 1997. Architecture and functional morphology of the skeletal apparatus of ozarkodinid conodonts. Philosophical Transactions of the Royal Society, London 352B, 1545–64.Google Scholar
Purnell, M. A. & Donoghue, P. C. J. 1998. Skeletal architecture, homologies and taphonomy of ozarkodinid conodonts. Palaeontology 41, 57102.Google Scholar
Purnell, M. A. & Donoghue, P. C. J. 2005. Between death and data: biases in interpretation of the fossil record of conodonts. Special Papers in Palaeontology 73, 725.Google Scholar
Pyle, L. J. & Barnes, C. R. 2002. Taxonomy, Evolution and Biostratigraphy of Conodonts from the Kechika Formation, Skoki Formation, and Road River Group (Upper Cambrian to Lower Silurian), Northeastern British Columbia. National Research Council of Canada Monograph Program. Ottowa, Canada: NRC Research Press. 227 pp.Google Scholar
Radcliffe, G. 1998. Biotic recovery of conodonts following the end-Ordovician mass extinction. Doctoral Dissertation, Durham University, UK. http:/etheses.dur.ac.uk/4686/Google Scholar
Repetski, J. E. 1997. Conodont age constraints on the Middle Ordovician black shale within the Ames Structure, Major County, Oklahoma. Oklahoma Geological Survey Circular 100, 363–69.Google Scholar
Repetski, J. E., Purnell, M. A. & Barrett, S. F. 1998. The apparatus architecture of Phragmodus. In Bagnoli, G. (ed.) Seventh International Conodont Symposium held in Europe (ECOS VII), Abstracts, 9192. Bologna: Tipografia Compositori.Google Scholar
Rexroad, C. B. & Nicoll, R. S. 1971. Summary of conodont biostratigraphy of the Silurian System of North America. Geological Society of America Memoir 127, 207–25.Google Scholar
Rieppel, O. & Kearney, M. 2002. Similarity. Biological Journal of the Linnean Society 75, 5982.Google Scholar
Sarmiento, G. N., Gutiérrez-Marco, J. C., Rodríguez-Cañero, R., Martín Algarra, A. & Navas-Parejo, P. 2011. A brief summary of Ordovician conodont faunas from the Iberian Peninsula. In Gutiérrez-Marco, J. C., Rábano, I. & García-Bellido, D. (eds) Ordovician of the World. Cuadernos del Museo Geominero 14, 505–14. Madrid: Instituto Geológico y Minero de España.Google Scholar
Satterfield, I. R. 1971. Conodonts and stratigraphy of the Girardeau Limestone (Ordovician) of southeast Missouri and southwest Illinois. Journal of Paleontology 45, 264–73.Google Scholar
Serpagli, E. 1983. The conodont apparatus of Icriodus woschmidti woschmidti Ziegler. Fossils and Strata 15, 155–61.Google Scholar
Sheehan, P. M. 2001. The Late Ordovician mass extinction. Annual Review of Earth and Planetary Science 29, 331–64.Google Scholar
Stauffer, C. R. 1935. Conodonts of the Glenwood Beds. Bulletin of the Geological Society of America 45, 126–68.Google Scholar
Stouge, S. 1984. Conodonts of the Middle Ordovician Table Head Formation, western Newfoundland. Fossils and Strata 16, 1145.Google Scholar
Stouge, S. & Rasmussen, J. A. 1996. Upper Ordovician conodonts from Bornholm and possible migration routes in the Parathetys Ocean. Bulletin of the Geological Society of Denmark 43, 5467.Google Scholar
Sweet, W. C. 1984. Graphic correlation of upper Middle and Upper Ordovician rocks, North American Midcontinent Province, U.S.A. In Bruton, D. L. (ed.) Aspects of the Ordovician System. Palaeontological Contributions from the University of Oslo 295, 2335. Oslo: Universitetsforlaget. 228 pp.Google Scholar
Sweet, W. C. 1988. The Conodonts: Morphology, Taxonomy, Paleoecology and Evolutionary History of a Long-extinct Animal Phylum. New York: Oxford University Press. 211 pp.Google Scholar
Sweet, W. C. & Bergström, S. M. 1962. Conodonts from the Pratt Ferry Formation (Middle Ordovician) of Alabama. Journal of Paleontology 36, 1214–52.Google Scholar
Szaniawski, H. 2015. New group of the Early Palaeozoic conodont-like fossils. Estonian Journal of Earth Sciences 64, 9194.Google Scholar
Szaniawski, H. & Bengtson, S. 1998. Late Cambrian euconodonts from Sweden. Palaeontologia Polonica 58, 729.Google Scholar
Theron, J. N. & Kovács-Endrödy, E. 1986. Preliminary note and description of the earliest known vascular plant, or an ancestor of vascular plants, in the flora of the Lower Silurian Cedarberg Formation, Table Mountain Group, South Africa. South African Journal of Science 82, 102–06.Google Scholar
Van Valen, L. 1982. Homology and causes. Journal of Morphology 173, 305–12.Google Scholar
Viira, V., Aldridge, R. J. & Curtis, S. 2006. Conodonts of the Kiviõli Member, Viivikonna Formation (Upper Ordovician) in the Kohtla section, Estonia. Proceedings of the Estonian Academy of Sciences, Geology 55, 213–40.Google Scholar
von Bitter, P. H. & Purnell, M. A. 2005. An experimental investigation of post-depositional taphonomic bias in conodonts. Special Papers in Palaeontology 73, 3956.Google Scholar
Wächtershäuser, G. 1992. Groundworks for an evolutionary biochemistry: the iron-sulphur world. Progress in Biophysics and Molecular Biology 58, 85201.Google Scholar
Walliser, O. H. 1964. Conodonten des Silurs. Abhandlungen der Hessischen Landesamtes Bodenforschung 41, 1106.Google Scholar
Wang, C.-y, Chen, L.-d, Wang, Y., & Tang, P. 2010. [Affirmation of Pterospathodus eopennatus Zone (Conodonta) and the age of the Silurian Shamao Formation in Zigui, Hubei, as well as the correlation of the related strata.] Acta Palaeontologica Sinica 49, 1028. [In Chinese, with English Abstract.]Google Scholar
Wang, C.-Y. & Aldridge, R. J. 2010. Silurian Conodonts from the Yangtze Platform, South China. Special Papers in Palaeontology 83, 5136.Google Scholar
Watson, S. T. 1988. Ordovician conodonts from the Canning Basin (W. Australia). Palaeontographica A 203, 91147.Google Scholar
Webers, G. F. 1966. The Middle and Upper Ordovician conodont faunas of Minnesota. Minnesota Geological Survey Special Publication Series 4, 1123.Google Scholar
Wickström, L. M. & Donoghue, P. C. J. 2005. Cladograms, phylogenies and the veracity of the conodont fossil record. Special Papers in Palaeontology 73, 185218.Google Scholar
Zhang, J. 1998. Conodonts from the Guniutan Formation (Llanvirnian) in Hubei and Hunan Provinces, South-Central China. Acta Universitatit Stockholmiensis, Stockholm Contributions in Geology 46, 1161.Google Scholar
Zhang, S. & Barnes, C. R. 2002a. A new Llandovery (early Silurian) conodont biozonation and conodonts from the Bescie, Merrimack, and Gun River Formations, Anticosti Island, Quebec. Journal of Paleontology 76(Supplement to No 2), 146.Google Scholar
Zhang, S. & Barnes, C. R. 2002b. Conodont bio-events, cladistics and response to glacio-eustasy, Ordovician–Silurian boundary through Llandovery, Anticosti Basin, Quebec. In Beaudoin, A. B. & Head, M. J. (eds) The Palynology and Micropalaeontology of Boundaries. Geological Society, London, Special Publications 230, 73104.Google Scholar
Zhao, Z. 2000. Paleozoic Stratigraphy and Conodonts in Xinjiang. Beijing: Petroleum Industry Press. 340 pp.Google Scholar