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Ascocerid cephalopods from the Hirnantian?–Llandovery stages of the southern Paraná Basin (Paraguay, South America): first record from high paleolatitudes

  • M. Cichowolski (a1) (a2), N.J. Uriz (a3), M.B. Alfaro (a3) and J.C. Galeano Inchausti (a4)


Ascocerid cephalopods are described for the first time from high paleolatitudes of Gondwana. Studied material was collected from the Hirnantian?–Llandovery strata of the Eusebio Ayala and Vargas Peña formations, Paraná Basin, southeastern Paraguay. The specimens are poorly preserved and were questionably assigned to the subfamily Probillingsitinae Flower, 1941, being undetermined at genus and species rank because diagnostic characters are not visible. A particular feature seen in our material is the presence of both parts of the ascocerid conch (the juvenile or cyrtocone and the mature or brevicone) joined together, which is a very rare condition in the known paleontological record. The specimens are interpreted as at a subadult stage of development because fully grown ascocerids would have lost the juvenile shell. A planktonic vertical migrant mode of life with a subvertical attitude is proposed for the juvenile, and a horizontal demersal nektonic mode for the adult form, as has been previously suggested. A subvertical orientation near the bottom is proposed for the subadult stage. We suggest that the immigration of ascocerids to southwestern Gondwana was possible through ocean currents that would carry the planktonic juveniles from low to high latitudes during the end-Ordovician postglacial transgression that flooded the intracratonic basins of the region.



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Aceñolaza, F.G., and Beresi, M.S, 2002, Ordovician nautiloids of Argentina, in Aceñolaza, F.G., ed., Aspects of the Ordovician System in Argentina: INSUGEO, Serie Correlación Geológica, v. 16, p. 107120.
Alfaro, M.B., Uriz, N.J., Cingolani, C.A., Bidone, A.R., and Galeano Inchausti, J.C., 2010, Hallazgo de la Biozona de Persculptograptus persculptus en la Formación Eusebio Ayala (Ordovícico Superior?–Llandovery), Paraguay Oriental: Décimo Congreso Argentino de Paleontología y Bioestratigrafía y Séptimo Congreso Latinoamericano de Paleontología, La Plata, Argentina, 2010, Actas, p. 41.
Alfaro, M.B., Uriz, N.J., Cingolani, C.A., Tortello, F., Bidone, A.R., and Galeano Inchausti, J.C., 2013, Graptolites and trilobites from the Eusebio Ayala Formation (Hirnantian?–early Llandovery), Paraná Basin, eastern Paraguay: Geological Journal, v. 48, p. 236247.
Aubrechtová, M., and Meidla, T., 2016, The oldest ascocerid cephalopod from the Silurian of Estonia and notes on the biogeography of the Order Ascocerida (class Cephalopoda): Estonian Journal of Earth Sciences, v. 65, p. 98104.
Babcock, L.E., Gray, J., Boucot, A.J., Himes, G.T., and Siegele, P.K., 1990, First Silurian conularids from Paraguay: Journal of Paleontology, v. 64, p. 897902.
Baldis, B.A., and Hansen, H., 1980, Trilobites dalmanítidos de Paraguay Oriental: Segundo Congreso Argentino de Paleontología y Bioestratigrafía y Primer Congreso Latinoamericano de Paleontología, Buenos Aires, Argentina, 1978, Actas, v. 1, p. 4967.
Barrande, J., 1867, Système silurien du centre de la Bohême 2, Céphalopodes, texte, pt. 1: Prague, Chez l’auteur, p. 1–712.
Barrande, J., 1877, Système silurien du centre de la Bohême, I.ère partie: Recherches Paléontologiques, v. 2, Classe de Mollusques, Ordre des Céphalopodes: Prague, Chez l’auteur, p. 743–505.
Benedetto, J.L., 2002, The Rhynchonellide brachiopod Eocoelia in the Llandovery of Paraguay, Paraná basin: Ameghiniana, v. 39, p. 307312.
Benedetto, J.L., Halpern, K., and Galeano Inchausti, J.C., 2013, High-latitude Hirnantian (latest Ordovician) brachiopods from the Eusebio Ayala Formation of Paraguay, Paraná Basin: Palaeontology, v. 56, p. 6178.
Boucot, A.J., and Racheboeuf, P.R., 1993, Biogeographic summary of the Malvinokaffric Realm Silurian and Devonian fossils, in Suarez-Soruco, R., ed., Fósiles y facies de Bolivia v. II. Invertebrados y Paleobotánica: Revista Técnica de YPFB, v. 13–14, p. 7175.
Boucot, A.J., de Melo, J.H., Santos Neto, E.V., and Wolff, S., 1991, First Clarkeia and Heterorthella (Brachiopoda; lower Silurian) occurrence from the Paraná Basin in Eastern Paraguay: Journal of Paleontology, v. 65, p. 312314.
Cecioni, G., 1953, Contribución al conocimiento de los nautiloideos Eo-Paleozoicos argentinos. Parte I: Protocycloceratidae–Cyclostomiceratidae: Boletín del Museo Nacional de Historia Natural, v. 26, p. 57109.
Cecioni, G., 1965, Contribución al conocimiento de los nautiloideos Eo-Paleozoicos argentinos. Parte II: Robsonoceratidae, Ellesmeroceratidae, Proterocameroceratidae, Baltoceratidae: Boletín del Museo de Historia Natural, v. 29, p. 124.
Cichowolski, M., and Rustán, J.J., 2017, First report of Devonian bactritids (Cephalopoda) from South America: Paleogeographic and biostratigraphic implications: Journal of Paleontology, v. 91, p. 417433.
Cichowolski, M., Rustán, J.J., and Uriz, N.J., 2018, Middle Palaeozoic cephalopods from southwestern Gondwana and their palaeobiogeographic meaning: Tenth International Symposium: Cephalopods —“Present and Past”—Fes, Morocco, 2018, Abstracts, p. 21.
Ciguel, J.H.G., Rosler, O., and Clerici, A.M.V.C., 1987, Skolithos verticalis e Skolithos ayalis, Formaçao Eusebio Ayala (Grupo Itacurubi, borda ocidental da Bacia do Paraná no Paraguai) e sua importancia no ambiente deposicional: Décimo Congreso Brasileiro de Paleontologia, Rio de Janeiro, Brasil, 1987, Anais, p. 253– 269.
Cingolani, C.A., Uriz, N.J., Alafaro, M.B., Tortello, F., Bidone, A.R., and Galeano Inchausti, J.C., 2011, The Hirnantian–early Llandovery transition sequence in the Paraná Basin, Eastern Paraguay, in Gutiérrez-Marco, J.C., Rábano, I., and García-Abellido, D, eds., Ordovician of the World: Cuadernos del Museo Geominero, v. 14, p. 103108.
Cocks, L.R.M., 2001, Ordovician and Silurian global geography: Journal of the Geological Society, v. 158, p. 197210.
Crick, R.E., 1988, Buoyancy regulation and macroevolution in nautiloid cephalopods: Senckenbergiana Lethaea, v. 69, p. 1342.
Cuvier, G., 1797, Tableau élémentaire de l’histoire naturelle des animaux: Paris, Baudouin, 710 p.
Degraff, J.M., Franco, F., and Orué, D., 1981, Interpretación geofísica y geológica del valle de Ypacaraí (Paraguay) y su formación: Revista de la Asociación Geológica Argentina, v. 36, p. 240256.
Dyck, M., 1991, Stratigraphie, Fauna, Sedimentologie und Tektonik im Ordoviziun und Silur von ost-Paraguay und vergleich mit den Argentinisch-Bolivianischen Anden [Ph.D. dissertation]: Hannover, Hannover University, 263 p.
Dzik, J., 1984, Phylogeny of the Nautiloidea: Palaeontologica Polonica, v. 45, 219 p.
Evans, D.H., 1993, The cephalopod fauna of the Killey Bridge Formation (Ordovician, Ashgill), Pomeroy, County Tyrone: Irish Journal of Earth Sciences, v. 12, p. 155189.
Figueredo, L., 1995, Descripción geológica del pozo RD 116 Santa Elena-Paraguay, in González Nuñez, M., Lahner, L., Cubas, N., and Adelaida, D., eds., Mapa Geológico de la República del Paraguay, Hoja Coronel Oviedo 5670 1:100.000: Cooperación Técnica BGR-MOPC, Asunción, 30 p.
Flower, R.H., 1941, Development of the Mixochoanites: Journal of Paleontology, v. 15, p. 523548.
Flower, R.H., 1962, Notes on the Michelinoceratida: New Mexico Institute of Mining and Technology, State Bureau of Mines and Mineral Resources, Memoir v. 10, p. 2140.
Flower, R.H., 1963, New Ordovician Ascoceratida: Journal of Paleontology, v. 37, p. 6985.
Foerste, A.F., 1928, Cephalopoda, in Twenhofel, W.H., ed., Geology of Anticosti Island: Geological Survey of Canada, Memoir 154, p. 257321.
Furnish, W.M., and Glenister, B.F., 1964, Nautiloidea-Ascocerida, in Moore, R.C, ed., Treatise on Invertebrate Paleontology, Part K, Mollusca 3: Lawrence, Geological Society of America and University of Kansas Press, p. K261K277.
Galeano Inchausti, J.C., and Poiré, D.G., 2006, Trazas fósiles de la Formación Eusebio Ayala (Silúrico inferior), Paraguay: Cuarto Congreso Latinoamericano de Sedimentología y Decimoprimera Reunión Argentina de Sedimentología, Bariloche, Argentina, 2006, Resúmenes, p. 103.
Godoy Ciguel, J.H., 1988, Tentaculites itacurubiensis n. sp. dos depósitos regressivos do Paraguai Oriental, Siluriano Inferior da Bacia do Paraná: Revista Brasileira de Geociencias, v. 18, p. 8892.
Harrington, H.J., 1950, Geología del Paraguay Oriental: Contribuciones Científicas, Serie E: Geología, Facultad de Ciencias Exactas, Física y Naturales, Universidad Buenos Aires, v. 1, p. 9–80.
Harrington, H.J., 1972, Silurian of Paraguay, in Beery, W.B.N., and Boucot, A.J., eds., Correlation of South American Silurian rocks: Boulder, Geological Society of America Special Papers, v. 133, p. 4150.
Hewitt, R.A., and Watkins, R., 1980, Cephalopod ecology across a late Silutian shelf tract: Neues Jahrbuch für Geologie und Paläontologie, v. 160, p. 96117.
Holland, C.H., 1999, The nautiloid cephalopod Order Ascocerida in the British Silurian: Palaeontology, v. 42, p. 683689.
Huxley, T.H., and Etheridge, R.A., eds., 1865, A Catalogue of the Collection of Fossils in the Museum of Practical Geology: London, G.E. Eyre and W. Spottiswoode, 381 p.
Hyatt, A., 1883–1884, Genera of fossil cephalopods: Proceedings of the Boston Society of Natural History, v. 22, p. 253–338.
Kesling, R.V., 1961, A new species of Billingsites, an ascoceratid cephalopod, from the Upper Ordovician Ogontz Formation of Michigan: Contributions from the Museum of Paleontology, the University of Michigan, v. 17, p. 77121.
Kröger, B., 2003, The size of the siphuncle in cephalopod evolution: Senckenbergiana Lethaea, v. 83, p. 3952.
Kröger, B., 2007, Concentrations of juvenile and small adult cephalopods in the Hirnantian cherts (Late Ordovician) of Porkuni, Estonia: Acta Palaeontologica Polonica, v. 52, p. 591608.
Kröger, B., 2008, Nautiloids before and during the origin of ammonoids in a Siluro-Devonian section of the Tafilalt, Anti-Atlas, Morocco: Special Papers in Palaeontology, v. 79, p. 5–110.
Kröger, B., 2013, The cephalopods of the Boda Limestone, Late Ordovician, of Dalarna, Sweden: European Journal of Taxonomy, v. 41, 110 p.
Kuhn, O., 1949, Lehrbuch der Palaozoologie: Stuttgart, E. Schweizerbart, 326 p.
Lindström, G., 1890, The Ascoceratidae and the Lituitidae of the Upper Silurian Formation of Gotland: Kungliga Svenska Vetenskaps-Akademiens Handlingar, v. 23, p. 154.
Manda, Š., 2008, Palaeoecology and palaeogeographic relations of the Silurian phragmoceratids (Nautiloidea, Cephalopoda) of the Prague Basin (Bohemia): Bulletin of Geosciences, v. 83, p. 3962.
Manda, Š., and Frýda, J., 2010, Silurian–Devonian boundary events and their influence on cephalopod evolution: Evolutionary significance of cephalopod egg size during mass extinctions: Bulletin of Geosciences, v. 85, p. 513540.
Manda, Š., and Kříž, J., 2006, Environmental and biotic changes in subtropical isolated carbonate during the Silurian Koslowskii Event, Pague Basin: GFF, v. 128, p. 161168.
Milani, E.J., and de Wit, M.J., 2007, Correlations between classic Paraná and Cape-Karoo basins of South America and southern Africa and their basin infills flanking the Gondwanides: Du Toit revisited, in Pankhurst, R.J., Trouw, R.A.J., Brito Neves, B.B., and de Wit, M.J., eds., West Gondwana: Pre-Cenozoic correlations across the South Atlantic Region: Geological Society of London, Special Publication v. 294, p. 319342.
Miller, A.K., 1932, The mixochoanitic cephalopods: University of Iowa Studies, Studies in Natural History, v. 14, 67 p.
Mutvei, H., 2012, Siphuncular structure in Silurian discosorid and ascocerid nautiloids (Cephalopoda) from Gotland, Sweden: implications for interpretation of mode of life and phylogeny: GFF, v. 134, p. 2737.
Mutvei, H., 2013, Characterization of nautiloid orders Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida: New superorder Multiceratoidea: GFF, v. 135, p. 171183.
Mutvei, H., 2015, Characterization of two new superorders Nautilosiphonata and Calciosiphonata and a new order Cyrtocerinida of the subclass Nautiloidea: siphuncular structure in the Ordovician nautiloid Bathmoceras (Cephalopoda): GFF, v. 137, p. 164174.
Steemans, P., and Pereira, E., 2002, Llandovery miospore biostratigraphy and stratigraphic evolution of the Paraná Basin, Paraguay – Palaeogrographic implications: Bulletin de la Société Géologique de la France, v. 173, p. 407414.
Strand, T., 1933, The Upper Ordovician cephalopods of the Oslo area: Norsk Geologiske Tidsskrift, v. 14, 117 p.
Stridsberg, S., 1985, Silurian oncocerid cephalopods from Gotland: Fossils and Strata, v. 18, p. 165.
Sweet, W.C., 1958, The Middle Ordovician of the Oslo region of Norway. 10. Nautiloid cephalopods: Norsk Geologiske Tidsskrift, v. 31, 178 p.
Tortello, M.F., Uriz, N.J., Alfaro, M.B., Cingolani, C.A., Bidone, A.R., and Galeano Inchausti, J.C., 2012, Trilobites and graptolites from the Vargas Peña Formation (early Silurian), Paraná Basin, Eastern Paraguay: Revue de Paléobiologie, Genève, v. v. spec. 11, p. 279298.
Turek, V., and Manda, Š., 2012, “An endocochleate experiment” in the Silurian straight-shelled cephalopod Sphooceras : Bulletin of Geosciences, v. 87, p. 767813.
Uriz, N.J., Alfaro, M.B., and Galeano Inchausti, J.C., 2008, Silurian (Llandovery) monograptids from the Vargas Peña Formation (Paraná Basin, Eastern Paraguay): Geologica Acta, v. 6, p. 181190.
Westermann, G.E.D., 1999, Life habits of nautiloids, in Savazzi, E., ed., Functional Morphology of the Invertebrate Skeleton: Chichester, Wiley, p. 263298.
Wood, G.D., and Miller, M.A., 1991, Distinctive Silurian chitinozoans from the Itacurubi Group (Vargas Peña Shale), Chaco Basin, Paraguay: Palynology, v. 15, p. 181192.


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