New Late Jurassic teleost remains from the Agardhfjellet Formation, Spitsbergen, Svalbard (original) (raw)
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Abundant new ichthyosaur material has recently been documented in the Slottsmøya Member of the Agardhfjellet Formation from the Svalbard archipelago of Norway. Here we describe a partial skeleton of a new taxon, Janusaurus lundi, that includes much of the skull and representative portions of the postcranium. The new taxon is diagnosed by a suite of cranial character states including a very gracile stapedial shaft, the presence of a dorsal process on the prearticular and autapomorphic postcranial features such as the presence of an interclavicular trough and a conspicuous anterodorsal process of the ilium. The peculiar morphology of the ilia indicates a previously unrecognized degree of morphological variation in the pelvic girdle of ophthalmosaurids. We also present a large species level phylogenetic analysis of ophthalmosaurids including new and undescribed ichthyosaur material from the Upper Jurassic of Svalbard. Our results recover all Svalbard taxa in a single unresolved polytomy nested within Ophthalmosaurinae, which considerably increases the taxonomic composition of this clade. The paleobiogeographical implications of this result suggest the presence of a single clade of Boreal ophthalmosaurid ichthyosaurs that existed during the latest Jurassic, a pattern also reflected in the high degree of endemicity among some Boreal invertebrates, particularly ammonoids. Recent and ongoing descriptions of marine reptiles from the Slottsmøya Member Lagerstätte provide important new data to test hypotheses of marine amniote faunal turnover at the Jurassic-Cretaceous boundary.
Lethaia, 2004
From the¯uvial Old Red Sandstone (ORS) of the Lower to Middle Devonian Wood Bay Formation (NW-Spitsbergen), a diverse trace fossil assemblage, including two new ichnotaxa, is described: Svalbardichnus trilobus igen. n., isp. n. is interpreted as the three-lobed resting trace of an early phyllocarid crustacean (Rhinocarididae). Cruziana polaris isp. n. yields morphological details that point towards a trilobite origin. This occurence of presumably marine trace makers in a¯uvial red bed sequence raises the question of whether we are dealing with marine ingressions that are not sedimentologically expressed, with homeomorphy, or with an adaptation of marine groups to nonmarine environments. & Ichnology, sedimentology, arthropods, Devonian, Old Red Sandstone (ORS), red beds, Svalbard, Spitsbergen.
Serpulid polychaete tubes are described from Volgian-Ryazanian sediments (?Pyrgopolon decorata (Stolley, 1912), ?Pyrgopolon aff. nodulosum (Lundgren, 1883)) and four contemporaneous hydrocarbon seep deposits (?Pyrgopolon aff. nodulosum, ?Pyrgopolon sp. A, Propomatoceros sp. A, Nogrobs aff. quadricarinata Münster in Goldfuss, 1831) from Spitsbergen, Svalbard. ese are the oldest serpulid tubes yet described from fossil hydrocarbon seep deposits, and comprise the most diverse fossil seep serpulid fauna known to date. e genera Propomatoceros Ware, 1975 and Nogrobs de Montfort, 1808 have their first fossil occurrence elsewhere in the Early Jurassic and then appear in the Svalbard seeps much later. is is the first report of ?Pyrgopolon de Montfort, 1808 from a fossil seep site.
Norwegian Journal of Geology, 2016
The Upper Jurassic-Lower Cretaceous in the Isfjorden area (central Spitsbergen), consisting mostly of dark shales, with local carbonate-seep deposits, have been analysed for marine palynomorphs and palynofacies. Two dinoflagellate cyst assemblage zones have been defined in the Slottsmøya Member (Agardhfjellet Formation). The palynostratigraphic zones are established with reference to δ 13 C org curves, and are correlated with Early Volgian to Late Ryazanian foraminiferal zones and ammonite zones from the same area. A Leiosphaeridia bloom at 45.62 m in the Janusfjellet profile is correlated with a comparable bloom recovered from several locations on the western Barents shelf. Palynofacies analysis is used to interpret relative sea-level changes and is also used to constrain the sequence stratigraphy of the studied sections at Janusfjellet and Knorringfjellet.