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Although a diverse range of aquatic vertebrates are documented from the Upper Cretaceous (mid-Campanian) marine strata of the Kristianstad Basin in southern Sweden, only chondrichthyans and marine amniotes have been described in detail to date. In contrast, coeval actinopterygians are virtually unreported, yet their remains are extremely abundant at most sampled localities. A comprehensive assessment of these fossils has identified the first Late Cretaceous actinopterygian fauna from the Fennoscandian Shield, incorporating indeterminate lepisosteids, the durophagous pycnodontid Anomoeodus subclavatus, the predatory pachycormid Protosphyraena sp., a large ichthyodectid, pachyrhizodontids resembling Pachyrhizodus, the enchodontid Enchodus cf. gladiolus and indeterminate small teleosts. These taxa are diagnosed mainly from isolated teeth and scales, implying substantial taphonomic loss prior to burial. Moreover, the prolific recovery of actinopterygian skeletal remnants in recent excavations suggests that historical collecting biases, rather than ecological paucity, have contributed to their under-representation in the Swedish Cretaceous record. Palaeobiogeographically, the Kristianstad Basin actinopterygians show compositional resemblance to assemblages from the Northern European Platform and the Western Interior Seaway of North America, advocating distributional communication across the Boreal proto-Atlantic Ocean.

Mesozoic dinosaur fossils are exceptionally rare in Scandinavia. The Swedish record is typically depauperate, with the Kristianstad Basin of Skane (Scania) yielding all of the known fossils from Swedish Cretaceous strata. Although highly fragmentary, these body remnants are important because they provide evidence of a relatively diverse fauna, including previously recognized hesperornithiform birds and leptoceratopsid ceratopsians, as well as indeterminate ornithopods that are confirmed here for the first time. In this paper, we describe three phalanges (from Asen) and an incomplete right tibia (from Ugnsmunnarna) from the Kristianstad Basin. One of the phalanges appears to pertain to a leptoceratopsid ceratopsian, providing further evidence of these small ornithischians in the Cretaceous sediments of Sweden. The other two phalanges are interpreted as deriving from small ornithopods similar to Thescelosaurus and Parksosaurus. The tibia appears to represent the first evidence of a non-avian theropod dinosaur in the Cretaceous of Sweden, with a previous report of theropod remains based on fish teeth having been corrected by other authors. The remains described herein provide important additions to the enigmatic dinosaurian fauna that inhabited the Fennoscandian archipelago during the latest Cretaceous.

Mesozoic dinosaur fossils are exceptionally rare in Scandinavia. The Swedish record is typically depauperate, with the Kristianstad Basin of SkÅne (Scania) yielding all of the known fossils from Swedish Cretaceous strata. Although highly fragmentary, these body remnants are important because they provide evidence of a relatively diverse fauna, including previously recognized hesperornithiform birds and leptoceratopsid ceratopsians, as well as indeterminate ornithopods that are confirmed here for the first time. In this paper, we describe three phalanges (from Åsen) and an incomplete right tibia (from Ugnsmunnarna) from the Kristianstad Basin. One of the phalanges appears to pertain to a leptoceratopsid ceratopsian, providing further evidence of these small ornithischians in the Cretaceous sediments of Sweden. The other two phalanges are interpreted as deriving from small ornithopods similar to Thescelosaurus

An assemblage of the burrowing ghost shrimp, Protocallianassa faujasi, is described, providing the first evidence of this decapod species from Sweden. The fossils occur in successions of the informal earliest late Campanian Belemnellocamax balsvikensis zone at Åsen and the latest early Campanian B. mammillatus zone at Ivö Klack, both in the Kristianstad Basin of NE Skåne. Numerous, heavily calcified chelipeds were found within a restricted bed at Å sen that was rich in carbonate-cemented nodules. Based on the burrowing lifestyle of modern mud shrimps, we interpret these nodules as infilled burrow chambers. The low abundance of molluscs within the Protocallianassa beds is also consistent with analogous extant communities, indicating that a similar ecologically exclusive relationship ruled within the Late Cretaceous shallowmarine ecosystems.

Potential traces of a mid-Campanian (83–73 Ma) marine extinction event have been documented as sequential faunal turnover in shallow coastal calcareous sands and calcarenite strata at the Åsen locality in the Kristianstad Basin of southern Sweden. The depositional succession at Åsen is conformably divided into the latest-early Campanian Belemnellocamax mammillatus belemnite Zone (a lateral equivalent of the northern European Belemnitella mucronata senior/Gonioteuthis quadrata gracilis Zone), and an overlying earliest-late Campanian Belemnellocamax balsvikensis Zone. The stratigraphically older B. mammillatus Zone assemblages comprise storm-accumulated remains (associated with coquina beds and oyster banks) that include selachians, chimaeroids, bony fish (pachycormiforms, pycnodontids, and teleosts), dyrosaurid crocodilians, elasmosaurid and polycotylid plesiosaurs, mosasaurs (mosasaurines, halisaurines, tylosaurines, and plioplatecarpines), and cheloniid sea turtles. Coeval invertebrates comprise abundant belemnites, bivalves, brachiopods, and echinoderms. This rich biodiversity abruptly declines up-sequence through the oyster bed layer and into the B. balsvikensis Zone; this is characterised by a sandier facies, which is exceptionally poor in reptile remains and manifests only small teleosts and sharks. Benthic molluscs and brachiopods also decline in abundance while worm tracks and decapod crustaceans (crabs) make a first appearance. Although, this observed change clearly corresponds to an environmental shift, it also correlates with a recognised trans-Atlantic mid-Campanian extinction event that affected warm-temperate to sub-tropical palaeolatitudinal belt assemblages in North America, and might have been part of a broader global phenomenon.

Although plesiosaurs and mosasaurs co-existed for about 35 million years at the end of the Cretaceous, the fossil record documenting interactions between these two groups of marine reptiles is meagre. The discovery of deeply incised scars on a limb bone of an immature polycotylid plesiosaur from the latest early Campanian (in the European two-fold division of the Campanian Stage) of the Kristianstad Basin, southern Sweden, is thus significant because it represents a rare example of predation or scavenging on an immature polycotylid plesiosaur by a large mosasaur.

To explain how the morphological differences between Rhamphorhynchoidea and Pterodactyloidea affect flight performances and life styles wings and claws of pterosaur fossils from collections in Uppsala and Munich have been measured. The measured specimens are from Jurassic limestones and shales in Solnhofen, Eichstätt and Holzmaden and include Dorygnathus, Campylognathoides, Rhamphorhynchus, Anurognathus, Pterodactylus, Germanodactylus and Gallodactylus. The measurements indicate differences between Rhamphorhynchoidea and Pterodactyloidea in wing construction and length of the claws. Different wing construction requires different flight performance. The shorter innermost part of the wing in Rhamphorhynchoidea indicates flapping flight while the longer innermost part of the wing in Pterodactyloids indicates soaring. Calculation on the narrowness of the wing has been done on three different specimens of Rhamphorhynchus, demonstrating a narrow distal part of the wing that probably was wider towards the body. Variation and divergence from the general morphological pattern creates diversity within both suborders, which results in three different flight performances in Rhamphorhynchoidea and two different flight performances in Pterodactyloidea. The three different flight performances proposed for Rhamphorhynchoidea are (1) Mixed gliding and flapping flight with broad wings, (2) Flapping flight with narrow wings and (3) Flapping flight with elliptical wings. The two different flight performances proposed for Pterodactyloidea are static and dynamic soaring. Measurements of the length of the claws indicate that the claws of the finger and toes were of the same size in Pterodactyloidea while the claws on the fingers were longer than the claws of the toes in Rhamphorhynchoidea, indicating tree climbing. Soaring flight, morphological characteristics similar to these in birds as well as development of hollow bones are all indications that pterosaurs probably had air sacs that we, Populärvetenskaplig sammanfattning: För 220-65 miljoner år sedan under tidsperioderna trias, jura och krita (dinosauriernas tidsålder), levde flygödlorna vid kuster, laguner och floder. Flygödlorna började flyga långt innan fåglar och fladdermöss och var därmed de första flygande ryggradsdjuren. Deras vingar var konstruerade på ett sätt som endast är karakteriserande för flygödlor. Den största delen av vingen bestod av ett förlängt fjärde finger vilket hjälpte till att spänna ut flyghuden från kroppen. Flyghuden bestod bland annat av strukturella fibrer kallade aktinofibriller som tillsammans med muskelfibrer kunde påverka vingens form under vila och flygning. Vingen bestod även av pteroidbenet, vilket är ett ben som man endast hittat hos flygödlor. Pteroidbenet hjälpte till att spänna ut den del av flyghuden som fanns vid över- och underarmen på vingens framkant. De hade troligtvis även flyghud spänd mellan bakbenen. Flygödlor kallas ibland för flygande reptiler, men hade ganska lite gemensamt med nutida reptiler eftersom de troligtvis var varmblodiga, hade hår på kroppen, levde ett aktivt flygande liv, klarade av att leva i kallare klimat och växte snabbt. Flygödlorna delas in i två underordningar: rhamphorhynchoida långsvansade flygödlor och pterodactyloida kortsvansade flygödlor. De långsvansade flygödlorna levde från slutet på trias till slutet på jura medan de kortsvansade flygödlorna levde från mellersta jura till slutet på krita. Antagligen utvecklades de kortsvansade flygödlorna från de långsvansade flygödlorna. De långsvansade är typiskt små flygödlor medan de senare kortsvansade flygödlorna kunde bli gigantiska med en vingbredd på 11-12m. Skelettets uppbyggnad skiljer sig mellan de lång- och kortsvansade flygödlorna. Olika uppbyggnad av skelettet skapar oftast olika funktioner som kunde påverka flygning och levnadssätt. I mitt examensarbete har jag försökt hitta ett samband mellan skillnader i skelettets uppbyggnad, levnadssätt, flygning och miljö genom m, Mätningar av vingar och klor av flygödlefossil från museer i Uppsala och München har gjorts för att försöka förklara hur de morfologiska skillnaderna mellan underordningarna Rhamphorhynchoidea och Pterodactyloidea avspeglar sig i flygödlornas flygfunktion och levnadssätt. Exemplaren av flygödlorna som ingår i mätningarna ligger i kalksten och skiffer från Solnhofen, Eichstätt och Holzmaden som avsattes under juraperioden och representeras av Dorygnathus, Campylognathoides, Rhamphorhynchus, Anurognathus, Pterodactylus, Germanodactylus och Gallodactylus. Mätningarna visade skillnader i vingkonstruktion och längd på klor mellan underordningarna Rhamphorhynchoidea och Pterodactyloidea. Skillnaderna i vingkonstruktion innebar skillnad i flygfunktion. Den kortare inre delen av vingen hos Rhamphorhynchoidea innebar flaxande flygning medan den längre inre delen av vingen hos Pterodactyloidea innebar segelflygning. Beräkningar av vingens längd/breddförhållande hos tre exemplar av Rhamphorhynchus tyder på att vingens yttre del var smal men att vingen blev bredare in mot kroppen. Variationer och avvikelser från det generella morfologiska mönstret skapade en mångfald inom de båda underordningarna, vilket resulterade i tre olika flygfunktioner hos Rhamphorhynchoidea och två olika flygfunktioner hos Pterodactyloidea. De tre olika flygfunktionerna inom Rhamphorhynchoidea är blandad glidflygning och flaxande flygning med breda vingar, flaxande med smala vingar samt flaxande med elliptiska vingar. De två olika flygfunktionerna inom Pterodactyloidea är dynamisk respektive statisk segelflygning. Mätning av klor visade att Pterodactyloidea har lika långa klor på fingrarna som på tårna medan Rhamphorhynchoidea har längre klor på fingrarna än på tårna. De längre klorna på fingrarna indikerar att Rhamphorhynchoidea kombinerade flygningen med klättrande i träd. För att kunna leva ett aktivt flygande liv hade flygödlorna luftsäckar, vilka sannolikt utvecklades från primitiva hos Rhamphorhyn