The case of the Carnian (Triassic) conodont genus Metapolygnathus Hayashi

Abstract

Successive evolutionary trends control the genera Paragondolella Mosher and Metapolygnathus Hayashi over the about 20 Ma long Aegean-Tuvalian timespan. In consideration of their evolutionary criteria, these genera have been retained together with Carnepigondolella Kozur and the two new genera proposed herein, Mazzaella (type species M. carnica) and Hayashiella (type species H. nodosa). Mazzaella n. gen. represents a Late Julian side branch of Metapolygnathus, harbouring a platform ornamentation similar to the several million years younger Tuvalian lineage of Carnepigondolella, issued from Hayashiella n. gen. that is intermediary between Metapolygnathus and Carnepigondolella, based on appearance and platform ornamentation.

Keywords

Carnian / conodont / phylogeny / evolutionary trend

References

Budurov K, Stefanov S. Gattung Gondolella aus der Trias Bulgariens. Trav. sur Géol. Bulg., sér. Paéeont., 1965, 115-127.

Budurov K J. Ancyrogondolella Triangularis gen. et sp. n. (Conodonta). Mitteilungen der Gesellschaft der Geologie-und Bergbaustudenten, 1972, 21: 853-860.

Budurov K J. Revision of the Late Triassic Platform Conodonts. Geologica Balcanica, 1977, 7: 31-48.

Budurov K J, Sudar M N. Late Triassic Conodont Stratigraphy. 1st International Senckenberg Conference and 5th European Conodont Symposium (ECOS V) Contributions IV. Papers on Conodonts and Ordovician to Triassic Conodont Stratigraphy. Courier Forschungsinstitut Senckenberg, 1990, 118: 203-240.

Buryi G I. Evolution of Late Triassic Conodont Platform Elements. Acta Micropaleontol. Sinica, 1996, 13(2): 135-142.

Carter E, Orchard M J. Intercalibration of Conodont and Radiolarian Faunas from the Carnian-Norian Boundary Interval in Haida Gwaii, British Columbia, Canada. The Triassic System. New Mexico Museum of Natural History and Science, 2013, 61: 67-92.

Hayashi S. The Permian Conodonts in Chert of the Adoyama Formation, Ashio Mountains, Central Japan. Earth Science (Chikyu Kagaku), 1968, 22: 63-77.

Hayashi S. Conodont Arekore. Geoscience Magazine, Chigaku Kenkyu, 1987, 37: 1-16.

Kozur H W. The Taxonomy of the Gondolellids Conodonts in the Permian and Triassic. 1st International Senckenberg Conference and 5th European Conodont Symposium (ECOS V): Contributions III, Papers on Ordovician to Triassic Conodonts, 1989, 117: 409-569.

Kozur H W. Integrated Ammonoid Conodont and Radiolarian Zonation of the Triassic. Hallesches Jahrbuch fur Geowissenschaften, Reihe B., 2003, 25: 49-79.

Krystyn L. The Microfauna of the Ladinian Karnian Hallstaetter Limestones of Saklibeli Taurus Mountains Turkey Part 1. Oesterreichische Akademie der Wissenschaften Mathematisch Naturwissenschaftliche Klasse Sitzungsberichte Abteilung I, 1975, 184(8–10): 259-340.

Mazza M, Furin S, Spötl C, . Generic Turnovers of Carnian/Norian Conodonts: Climatic Control or Competition?. Palaeogeography, Palaeoclimatology, Palaeoecology, 2010, 290: 120-137.

Mazza M, Cau A, Rigo M. Application Numerical Cladistic Analyses to the Carnian-Norian Conodonts: A New Approach for Phylogenetic Interpretations. Journal of Systematic Palaeontology, 2012, 10(3): 401-422.

Mazza M, Rigo M, Gullo M. Taxonomy and Biostratigraphic Record of the Upper Triassic Conodonts of the Pizzo Mondello Section (Western Sicily, Italy), GSSP Candidate fort the Base of the Norian. Rivista Italiana di Paleontologia e Stratigrafia, 2012, 118(1): 85-130.

Mock R. Gondolella Carpathica n. sp., Eine Wichtige Tuvalische Conodontenart. Geol. Paläont. Mitt. Innsbruck, 1979, 171-174.

Mosher L C. Triassic Conodonts from Western North America and Europe and Their Correlation. Journal of Paleontology, 1968, 42: 895-946.

Mosher L C. Triassic Conodonts from British Columbia and the Northern Arctic Islands. Geological Survey of Canada, 1973, 222: 141-192.

Orchard M J. Epigondolella Populations and Their Phylogeny and Zonation in the Norian (Upper Triassic). Fossils and Strata, 1983, 15: 177-192.

Orchard M J. Late Triassic Conodont Biochronology and Biostratigraphy of the Kunga Group, Queen Charlotte Islands, British Columbia. Evolution and Hydrocarbon Potential of the Queen Charlotte Basin, British Columbia. Geological Survey of Canada, 1991, 569: 173-193.

Orchard M J. Upper Triassic Conodont Biochronology and New Index Species from the Canadian Cordillera. Ordovician to Triassic Conodont Paleontology of the Canadian Cordillera. Geological Survey of Canada, 1991, 335: 299-335.

Orchard M J. Conodont Lineages from the Carnian/Norian Boundary at Black Bear Ridge, Northern British Columbia. The Global Triassic. New Mexico Museum of Natural History and Science, 2007, 41: 331-332.

Orchard M J. A Proposed Carnian-Norian Boundary GSSP at Black Bear Ridge, Northest British Columbia, and a New Conodont Framework for the Boundary Interval. Albertiana, 2007, 36: 130-141.

Orchard M J. Five New Genera of Conodonts from the Carnian-Norian Boundary Beds of Black Bear Ridge, Northeast British Columbia, Canada. The Triassic System. New Mexico Museum of Natural History and Science, 2013, 61: 445-437.