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The first record of the mosasaur Clidastes from Europe and its palaeogeographical implications

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Lindgren J., Siverson M.

Acta Palaeontologica Polonica

2004

tom 49

nr 2

Remains of the mosasaur Clidastes propython in marine strata of latest early Campanian age from the Kristianstad Basin, southern Sweden, represent the first record of Clidastes outside of North America. The material consists of shed marginal and pterygoid tooth−crowns, and vertebrae (including eleven associated cervicals and dorsals from a juvenile). The majority of the teeth and skeletal elements can be referred to juveniles (mostly in the estimated 2–3 m total body length range), but large, presumably adult individuals (up to an estimated total length of 6 m) are also represented. Available data indicate that the Kristianstad Basin population of C. propython represents a short−lived migration, most likely from the Mississippi Embayment in North America. The local extinction of Clidastes in southern Sweden, tentatively placed at the early/late Campanian boundary (sensu germanico), may coincide with that in the Western Interior Seaway and Gulf Coast of North America. Within the Kristianstad Basin area, Clidastes occurs in high−energy, shallow water deposits, where it is the most common mosasaur. This finding is in stark contrast to recent publications suggesting that Clidastes inhabited mainly off−shore, deeper waters.

Late Cretaceous sharks Cretoxyrhina and Cardabiodon from Montana, USA

100%

Siverson M., Lindgren J.

Acta Palaeontologica Polonica

2005

tom 50

nr 2

The middle part of the Cretaceous represents a time of high diversity and rapid rates of dental evolution in lamniform sharks. Several species had a very wide spatial distribution with recorded occurrences in both hemispheres. We have examined isolated teeth of Cretoxyrhina and Cardabiodon from eastern Russia, Mangyshlak in Kazakhstan, and the Western Interior of the USA. The material indicates that samples of isolated teeth of the two genera have high potential in intercontinental correlation of the upper Albian to mid−Turonian interval in mid−palaeolatitude deposits, poor in other age−diagnostic fossil groups. The utilization of these lamniforms in mid−Cretaceous biostratigraphy is currently hampered by the nearly total absence in the literature of well illustrated, well dated and sufficiently large samples of isolated teeth of the two genera. As a first step towards the establishment of an intercontinental elasmobranch zonation for mid−Cretaceous strata in temperate palaeo−regions, we describe and illustrate samples of teeth of Cardabiodon venator sp. nov. and Cretoxyrhina mantelli from the lower middle Turonian Collignoniceras woollgari regulare Zone in the Fairport Member of the Carlile Shale in east−central Montana, USA. These samples could serve as reference points for future biostratigraphic studies of Cretoxyrhina and Cardabiodon. The extinction of Cretoxyrhina may be diachronous, as regional last appearance data range from the upper Santonian (Marsupites testudinarius Zone) in Western Australia to the uppermost lower Campanian (informal Belemnellocamax mammillatus zone; a lateral equivalent to the German Gonioteuthis quadrata gracilis/Belemnitella mucronata Zone) in southern Sweden.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Lindgren J.

2 Siverson M.

1 2005

1 2004

Wyniki wyszukiwania

The first record of the mosasaur Clidastes from Europe and its palaeogeographical implications

Late Cretaceous sharks Cretoxyrhina and Cardabiodon from Montana, USA