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VIVIANNE BERG-MADSEN 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1986,19(1):67-80
A rich material of echinoderm fragments from two Middle Cambrian stratigraphical levels on Bornholm are preserved due to phosphatization of the original calcitic stereom. Preservation of echinoderms in this way - not previously recorded from the Middle Cambrian - permits detailed analysis of the three-dimensional stereom structure. Identifiable are fragments of stylophorans and eocrinoids. Stem columnals, most likely from eocrinoids, show a wide and advanced morphological variation indicating articulation similar to that of crinoids. The material from the Exsulans Limestone/Kalby marl ( Ptychagnostus gibbus Zone) represents stem-bearing cystoids older than Akadocrinus from Bohemia. The Andrarum Limestone ( Sole-nopleura brachymetopa Zone) contains echinoderm fragments from a higher stratigraphical level, a level correlatable with that from which the oldest North American stem–bearing cystoid, Eustypocystis , has been recorded. 相似文献
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Lars B. Clemmensen Jesper Milàn Gunver K. Pedersen Anne B. Johannesen Connie Larsen 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2014,47(4):485-493
Fluvial palaeochannels of coastal plain sediments of the Lower Jurassic Sose Bugt Member of the Rønne Formation exposed in the coastal cliffs at Sose Bugt, Bornholm, contain abundant dinosaur or other large vertebrate tracks in the form of deformation structures exposed in vertical section. The tracks are represented by steep‐walled, flat‐to‐concave‐bottomed depressions, with a raised ridge at each side. The tracks are filled with laminated sediments, draping the contours of the bottom of the depression. Underprints, stacked concave deformations beneath the prints, are present beneath each track. Contemporary Upper Triassic – Lower Jurassic strata from southern Sweden and Poland contain a diverse track fauna, supporting our interpretation. This is the earliest evidence of dinosaur activity in Denmark. 相似文献
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The dinosaur fauna of the palynologically dated lower Berriasian Skyttegård Member of the Rabekke Formation on the Baltic island of Bornholm, Denmark, is represented by isolated tooth crowns. The assemblage is restricted to small maniraptoran theropods, assigned to the Dromaeosauridae incertae sedis and Maniraptora incertae sedis. The dromaeosaurid teeth are characterized by their labiolingually compressed and distally curved crowns that are each equipped with a lingually flexed mesial carina and a distinctly denticulated distal cutting edge. A morphologically aberrant tooth crown (referred to as Maniraptora incertae sedis) has triangular denticles of uneven width, a feature occasionally found in Upper Cretaceous hesperornithiform toothed diving birds, but also in premaxillary teeth of the velociraptorine Nuthetes from the Lower Cretaceous of England. 相似文献
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An enigmatic,diminutive theropod footprint in the shallow marine Pliensbachian Hasle Formation,Bornholm, Denmark
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Jesper Milàn Finn Surlyk 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2015,48(4):429-435
A well‐preserved three‐toed footprint, measuring 34 mm in length from a very small predatory dinosaur with an estimated hip height of 153 mm and a total body length around 50 cm including tail, is reported from the type section of the marine Lower Jurassic (Pliensbachian), Hasle Formation on the Danish island of Bornholm in the Baltic Sea. The morphology of the footprint is similar to the ichnogenus Stenonyx Lull 1904 from the contemporaneous Pliensbachian Szydlowek site in Poland. Apart from the Polish material, footprints from diminutive dinosaurs are rare and reported from few other localities around the world. The occurrence of a diminutive dinosaur footprint in a shallow marine sandstone is enigmatic. The well‐defined morphology of the footprint, together with the very small size of the trackmaker, excludes the possibility that the track was emplaced by a swimming or wading animal. At the type locality where the footprint was found the formation consists of ferruginous coarse siltstone and very fine‐grained sandstone, showing hummocky and swaley cross‐stratification and rare large‐scale trough cross‐bedding and planar lamination. Deposition took place mainly in the upper shoreface in a storm‐dominated environment 1 km west of the N?S‐oriented faulted coastline. The formation becomes thinner and finer grained with heterolithic intercalations towards the south, indicating coast‐parallel transport in this direction. The extreme uniformity in sedimentary facies as seen in two nearby fully cored boreholes shows that the accommodation space created by rapid subsidence along the fault was continuously filled in to upper shoreface level by rapid longshore sediment influx from the north. In quiet periods with easterly winds and extreme low‐water low tide, the small dinosaur creating the newly found footprint is interpreted to have walked in shallow beach pools, thus explaining the strange occurrence of the footprint in a marine deposit. 相似文献
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