Jan Rees

Hybodont sharks from the Middle Jurassic of the Inner Hebrides, Scotland

Non-marine Bathonian (Middle Jurassic) strata on the Isles of Eigg and Skye in Scotland have yielded fossil remains of eight hybodont shark taxa. Faunas from several horizons within the Lealt Shale and Valtos Formation on the Isle of Eigg include six species: Hybodus grossiconus , Hybodus sp. 1, Hybodus sp. 2, Lissodus leiodus , L. leiopleurus and Parvodus pattersoni . Large collections of teeth of L. leiodus and L. leiopleurus enable a better understanding of the dentitional patterns of the two species and their differential diagnosis. Surface-collecting from exposures of the Kilmalaug Formation on the Isle of Skye yielded hybodont teeth of two taxa: Hybodus sp. 3 and Acrodus caledonicus sp. nov. The occurrence of Acrodus in the Bathonian of Scotland is one of the youngest known occurrences of this genus, and the only non-marine record in the European Jurassic. Collectively, the hybodont assemblages from the Scottish Bathonian provide evidence that non-marine faunas of the group were specifically diverse in the Middle Jurassic.

The first Mesozoic mammal from Scandinavia

Abstract Lowermost Cretaceous (Berriasian) strata of the Skyttegård Member (Rabekke Formation, Nyker Group) on the island of Bornholm, Denmark, have yielded a diverse terrestrial micro-vertebrate fauna. The assemblage is unique in several aspects, including e.g. the first Mesozoic mammal from Scandinavia. Here, we describe the mammal fossil, identified as a multituberculate upper premolar. The tooth is tentatively assigned to the monospecific genus Sunnyodon, as it shares the largest number of diagnostic dental features with the approximately coeval S. notleyi from the Purbeck Limestone Formation in southernmost England.

On the enigmatic neoselachian Agaleus dorsetensis from the European Early Jurassic

Abstract One of the most enigmatic Early Jurassic neoselachians is Agaleus dorsetensis Duffin & Ward, 1983b, a species ranging exclusively through the Sinemurian and Pliensbachian and having a known geographical distribution restricted to northwest Europe. An investigation of the dental microstructure, in combination with the morphology of recently collected parasymphyseal and posterior teeth, provide new insights regarding the systematic affinities of A. dorsetensis. Teeth of this species possess a triple-layered enameloid with a Parallel-Bundled Enameloid made up of densely arranged longitudinal bundles of crystallites with numerous radial bundles, which is quite unlike that of Late Triassic neoselachian sharks. An emended diagnosis is provided and the heterodonty pattern is established as strong and monognathic. In combination with dental morphology, the results from the microstructure analysis confirm that A. dorsetensis is a modern neoselachian belonging to the Galea.

Amphibians and small reptiles from the Berriasian Rabekke Formation on Bornholm, Denmark

Abstract A diverse microvertebrate assemblage has been extracted from a limnic lowermost Cretaceous (Berriasian) stratum on the island of Bornholm, Denmark. The assemblage includes numerous remains of a wide variety of vertebrate groups including fishes, amphibians, reptiles and mammals. Herein, we describe the amphibian and reptilian (excluding Archosauria and Chelonia) part of the assemblage including indeterminate salamanders, frogs and lizards. The former findings are of particular interest as they represent the first occurrence of Mesozoic amphibians in Denmark.