Late late Albian (Early Cretaceous) shark teeth from Annopol, Poland

Abstract

Siversson, M. & Machalski, M., February 2017. Late late Albian (Early Cretaceous) shark teeth from Annopol, Poland. Alcheringa 41, 433–463.

Screen washing of the condensed phosporite-bearing sands at the top of the Albian succession at Annopol, Poland, produced 789 selachian teeth of which 264 are determinable to at least genus level. The sediment type and methods of processing prevented recovery of small-toothed taxa, resulting in an assemblage comprising 13, mostly large-toothed taxa. Lamniformes dominates with Dwardius sp. being, by far, the most common taxon. Observations on vertical distribution and preservation of the teeth (with focus on the adhered phosphatic matrix), coupled with biostratigraphic ranges of co-occurring ammonites, indicate that the majority of the shark material is attributable to the Mortoniceras rostratum or, more probably, M. perinflatum Zone (late late Albian; mid-‘Vraconnian’). This is compatible with the composition of the shark assemblage, characterized by the co-occurrence of Paraisurus sp. aff. P. compressus, Cretoxyrhina vraconensis and Squalicorax teeth with strong serrations on the cutting edges. The tightly curved basal edge of the root in lateral teeth of C. vraconensis conforms to that of teeth from the Pawpaw Formation of Texas (M. rostratum Zone) and differs from the more divergent root lobes in younger specimens from the uppermost Albian and/or lowermost Cenomanian of Kolbay, Mangyshlak. Some specimens in the studied assemblage are probably older, within the range from the middle to earliest late late Albian. The strong numerical dominance of either Cretoxyrhina or Dwardius in late late Albian to early Cenomanian selachian faunas indicates competitive exclusion in these similar-sized, apex predatory sharks.

Mikael Siversson* [[email protected]], Department of Earth and Planetary Sciences, Western Australian Museum, 49 Kew Street, Welshpool, Western Australia 6106, Australia; Marcin Machalski [[email protected]], Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warszawa, Poland. *Also affiliated with: Department of Environment & Agriculture, Curtin University, Kent Street, Bentley, WA 6102, Australia.

Keywords:

• Annopol
• Vraconnian
• Albian
• selachians
• Cretaceous
• teeth
• condensed

Acknowledgements

The major part of the present study (including most of the fieldwork and research visit by MS to Warszawa in 2014) was financed by the Polish National Centre of Science grant ‘The Albian phosphorite horizon at Annopol—a unique “Fossil Lagerstätte” in Poland and its palaeobiological significance’ to MM (decision DEC-2012/05/B/ST10/00710). To a lesser degree, this project was also financed by an earlier grant from the Polish National Centre of Science (no. N N307 529238) to MM. We thank Wiesław Liwiński (Mayor of Annopol) for enthusiastic support, and Agnieszka Kapuścińska, Adam Zaremba, Maciej Duda, Maciej Małysiak, Krzysztof Nejbert, Michał Andziak and the OSP Sucha Wólka fire fighters, for their assistance in fieldwork at the Kopiec locality. Aleksandra Hołda-Michalska is acknowledged for computer processing of Figs 1 and 2, and Piotr Gryz and Oksana Malczyk for assistance with cataloguing the collection. David Ward, Natural History Museum, London, assisted with literature and comparative material from the Kolbay site. Charlie Underwood, University of London, provided us with photographs of Synechodus tenuis specimens from the Lower Greensand, kept in the Natural History Museum, London. David Jolly provided photographs of Cretodus specimens from the Aube region, France. Evgeny Popov, Saratov University, assisted with translation of Russian literature. Working facilities for MS were provided by the Department of Earth and Planetary Sciences, Western Australian Museum. Constructive comments from an anonymous reviewer and the handling editor improved the manuscript.