Bulletin of the Geological Society of Denmark • Volume 47/2

An Early Cretaceous scincomorph lizard dentary from Bornholm, Denmark

Rees, J.: An Early Cretaceous scincomorph lizard dentary from Bornholm, Denmark. Bulletin of the Geological Society of Denmark, Vol. 47, pp. 105–109. Copenhagen.

Abstract: A single dentary of a terrestrial lizard was recently discovered in the lowermost part of the Early Cretaceous Jydegård Formation on the island of Bornholm, Denmark. The general outline of the dentary, including a large, partly open Meckelian groove, a coronoid process and a fairly large subdental shelf, in combination with the lack of an intramandibular septum, strongly indicate scincomorph affinity. Further identification is at present not possible as there are a limited number of characters preserved on the dentary. This is the first terrestrial Mesozoic lizard recorded from Scandinavia.

Key words: Lizard, dentary, Scincomorpha, Early Cretaceous, Bornholm, Denmark.

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The Quaternary arthropod fauna of Greenland: a review with new data

Bennike, O., Björck, S., Böcher, J. & Walker, I. R.: The Quaternary arthropod fauna of Greenland: a review with new data. Bulletin of the Geological Society of Denmark, Vol. 47, pp. 111–134. Copenhagen.

Abstract: Arthropod fossils from Quaternary deposits in Greenland are considered. The few occurrences of Early and Middle Pleistocene age have yielded only three species of barnacles. This contrasts sharply with the last interglacial stage which is represented by many sites, from which a range of marine, lacustrine and terrestrial crustaceans and insects are reported. The only secure late glacial sediments from Greenland are found in the far south, and only a few taxa of arthropods have so far been identified from these. The best dated and richest faunas come from the Holocene. Most records of insects are from the late Holocene, but there are also a number of finds from the early and mid Holocene. Arthropods are considered good palaeoclimate indicators, because they are generally dispersed quicker, for example, than vascular plants. This group of animals is also highly useful for reconstructing former ecological conditions, because they occupy such a wide range of biotopes. A total of about 105 taxa have been reported so far, but several groups of arthropods, such as marine ostracodes, chironomids and oribatids, have received little attention, and many more taxa can be expected when these groups are being studied in the future.

Key words: Greenland, Quaternary, biogeography, palaeoecology, Arthropoda, Insecta, Crustacea, Cladocera, Ostracoda.

O. Bennike [ ], Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen NV, Denmark. S. Björck, Department of Quaternary Geology, Lund University, Tornavägen 13, SE-223 63 Lund, Sweden. J. Böcher, Zoological Museum, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark. I. R. Walker, Departments of Biology, and Earth & Environmental Sciences, Okanagan University College, 3333 College Way, Kelowna, British Columbia, Canada V1V 1V7. 28 April 2000.

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Gradualistic evolution in Belemnitella from the middle Campanian of Lower Saxony, NW Germany

Christensen, W.K.: Gradualistic evolution in Belemnitella from the middle Campanian of Lower Saxony, NW Germany. Bulletin of the Geological Society of Denmark 47, 135–163. Copenhagen.

Abstract: Nine samples of the Belemnitella lineage, including the uppermost Lower and lower Upper Campanian B. mucronata and the uppermost lower Upper Campanian B. misburgensis sp. nov., from the expanded uppermost Lower and lower Upper Campanian succession of the Lehrte West Synclinee east of Hannover, Lower Saxony, northern Germany have been subjected to univariate and bivariate statistical analyses. The succession consists of monotonous marly limestones and calcareous marls, which were deposited during 4–5 m.y. in a fairly stable environment. Based on superficial resemblance alone the nine samples are nearly identical, but trends have been recognized in the morphological characters when treated quantitatively. Three characters, the length from the apex to the protoconch, the slenderness of the guard and the alveolar angle, show evolutionary reversals (socalled zig-zag evolution) with net decreases or increases. The Schatzky distance shows stasis in B. mucronata and decreases in B. misburgensis sp. nov. The fissure angle displays unidirectional evolution and increases gradually. These morphological changes are interpreted as long term phyletic gradualism, although this model of evolution has almost universally been depicted as one of unidirectional change. B. misburgensis sp. nov. is closely allied to B. mucronata (its ancestor), but differs in its slightly smaller and more slender guard, in addition to its smaller Schatzky distance and larger fissure angle. B. praecursor is recorded from the uppermost five metres of the Lower Campanian, and this is the first record of this species from the highest Lower Campanian of northern Germany. The uppermost Lower and Lower Upper Campanian belemnite assemblages of the Misburg/Höver area in northern Germany are reviewed. The Upper Campanian Belemnitella successions of Norfolk in England, the Maastricht-Liège district in The Netherlands and Belgium, the Mons Basin in southern Belgium, Scania in southern Sweden and the Misburg-Höver area in northwest Germany are compared and contrasted.

Key words: Belemnites, Belemnitella praecursor, B. mucronata, B. misburgensis sp. nov., Campanian, Lehrte West Syncline, Lower Saxony, northwest Germany, biometry, gradualistic evolution, Upper Campanian Belemnitella successions.

Walter Kegel Christensen [ ], Geological Museum, University of Copenhagen, Øster Voldgade 5–7, DK-1350-Copenhagen, Denmark. 11 September 2000.

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