Jørn Hurum | University of Oslo (original) (raw)
Papers by Jørn Hurum
PeerJ, Oct 12, 2018
The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marin... more The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marine reptiles, including four named taxa of ophthalmosaurid ichthyosaurs. One of these, Palvennia hoybergeti, is based on the single holotype specimen (SVB 1451) with an incomplete skull. A newly discovered specimen (PMO 222.669) with a disarticulated but largely complete skull and anterior postcranium is described, which considerably expands our knowledge of this taxon. Two additional new ophthalmosaurid specimens with pectoral girdles from the same member are described. The taxonomic utility of the ophthalmosaurid pectoral girdle is contentious, and an assessment of seven pectoral girdles from the Slottsmøya Member provides a basis for addressing this question via a 2D landmark principal component analysis of baracromian coracoids. The analysis reveals a taxonomic signal in the coracoids but also highlights the degree of individual variation. Commonly used phylogenetic characters do not fully encapsulate the degree of variation seen in coracoids and in some cases combine analogous features.
Collections, Apr 21, 2023
Acta Palaeontologica Polonica, 1997
Mongolian Late Cretaceous multituberculates (except Buginbaatar) form a monophyletic group for wh... more Mongolian Late Cretaceous multituberculates (except Buginbaatar) form a monophyletic group for which the suborder Djadochtatheria is proposed. Synapomorphies of Djadochtatheria are: large frontals pointed anteriorly and deeply inserted between the nasals, U-shaped fronto-parietal suture, no frontal-maxilla contact, and edge between palatal and lateral walls of premaxilla. Large, rectangular facial surface of the lacrimal exposed on the dorsal side of the cranial roof is present in all djadochtatherians, but may be a plesiom\\orphic feature. It is also possible that in djadochtatherians the postglenoid part of the braincase is relatively longer than in other multituberculates. Djadochtatherims have an arcuate p4 (secondarily subtrapezoidal in Catopsbaatar) that does not protrude dorsally over the level of the molars (shared with Eucosmodontidae), I3 placed on the palatal part of the premaxilla (shared with the eucosmodontid Stygimys and the cimolomyid Meniscoessus). The small number of cusps on the upper and lower molars and no more than nine ridges on p4 are possibly plesiomorphies for Djadochtatheria. The djadochtatherian Nessovbaatar multicostatus gen. et sp. n., family incertae sedis from the Barun Goyot Formation is proposed. New specimens of the djadochtatherian genera Kryptobaatar, ?Djadochtatherium, and Kamptobaatar are described and revised diagnoses of these taxa and Sloanbaatar are given. A cladistic analysis of Mongolian Late Cretaceous multituberculates (MLCM), using Pee-Wee and NONA programs and employing 43 dental and cranial characters, 11 MLCM taxa, five selected Late Cretaceous or Paleocene multituberculate genera from other regions, and a hypothetical ancestor based on the structure of Plagiaulacoidea, is performed. The Pee-Wee program yielded two equally fit trees that confirm the monophyly of MLCM excluding Buginbaatal: Kryptobaatar, Djadochtatherium, Catopsbaatar, and Tombaatar form a clade, for which the family Djadochtatheriidae is proposed. Chulsanbaataris the sister taxon of this clade. Bulganbaatar and Nemegtbaatar are the sister group of all other djadochtatherians. Kamptobaatar, Sloanbaatar, and Nessovbaatar form a separate clade in the Pee-Wee tree. The NONAprogram yielded thirty equally parsimonious trees and a strict consensus tree with a poor resolution.
Acta Palaeontologica Polonica
The marine Middle Triassic sediments of Svalbard are rich in fossiliferous material and are parti... more The marine Middle Triassic sediments of Svalbard are rich in fossiliferous material and are particularly well-known for marine reptile fossils. Here, we present a new specimen of the small-bodied mixosaurid ichthyosaur Phalarodon fraasi from the Botneheia Formation. PMO 235.393 is unusual in being the first three-dimensional mixosaurid skull recovered from this formation, allowing us to use computed tomography to reconstruct the obscured right side of the cranium, resulting in the first 3D model available for a mixosaurid ichthyosaur. Although separated into different slabs, the specimen preserves most of the dermatocranium as well as some partial post-cranial elements. In particular, the rostrum, external naris, dentition, quadrate and sclerotic ring are well-preserved. This methodology gave new insights into the adaptations this taxon has to durophagy, as well as a detailed look at the heterodont dentition present in PMO 235.393. After comparing with other Phalarodon specimens, it was clear that the maxillary heterodonty of this genus is a synapomorphy. As such this was added as a new character in our phylogenetic analysis, supporting the separation of Phalarodon and Mixosaurus.
The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic ... more The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic Norway) is presented and described. The specimen, a femur, was collected from the Zillerberget member of the Carolinefjellet Formation at Schönrockfjellet in 1962 and was recently re-discovered. The bone is referred to ?Avialae based on a combination of characters, including extreme thinness of the cortex, a well-developed head, and the presence of a patellar sulcus. From biostratigraphic analysis, it is demonstrated that the bone comes from the lower part of the middle Albian. This find is important because the Early Cretaceous fossil record of Avialae remains poorly documented in most parts of the World and is non-existent in Arctic strata. A general overview of the geology and stratigraphy of the Lower Cretaceous in Spitsbergen is presented in order to provide context for the fossil occurrence, with a particular focus on the Aptian and Albian sedimentary system and with the first-ever report on the entire stratigraphy on the east face of Schönrockfjellet.
Norwegian Journal of Geology, 2018
The Agardhfjellet Formation (Middle Jurassic to lowermost Cretaceous) of Svalbard (Norwegian Arct... more The Agardhfjellet Formation (Middle Jurassic to lowermost Cretaceous) of Svalbard (Norwegian Arctic) is well known for its abundant and unique marine reptile fauna, of ichthyosaurs and plesiosaurs. In an attempt to reconstruct the palaeoecology and palaeoenvironment of the Agardhfjellet Formation, a study of the invertebrate fauna, geochemistry and stratigraphy was conducted. During this study numerous small vertebrate fossils were encountered. Only a few reports of Jurassic teleost from the Arctic were known previously, from the Agardhfjellet Formation on Svenskøya, Kong Karls Land, described as Leptolepis nathorsti, and at Lardyfjellet, East Spitsbergen. We describe more teleost material from the Kimmeridgian and Volgian of the Agardhfjellet Formation in central Spitsbergen and assign a new age, Kimmeridgian, to the original material. This new material also provides more information on the palaeoecology of the Jurassic of Svalbard, showing that fish were probably common in the pelagic fauna of central Spitsbergen together with the better known cephalopods, and could have been important elements of the diet of the marine reptiles.
We present results of the first studies of the bone microstructure of early mammals, based on the... more We present results of the first studies of the bone microstructure of early mammals, based on the Early Jurassic Morganucodon, the Late Cretaceous multituberculates, Kryptobaatar and Nemegtbaatar, and the Late Cretaceous eu− therians Zalambdalestes and Barunlestes. Our results show that the two eutherian taxa grew relatively slowly with pe− riodic pauses in growth indicated by the presence of rest lines, while the multituberculates and Morganucodon had a faster rate of bone formation that suggests an overall rapid growth rate that slowed down later in ontogeny. Compari− sons of the early mammalian bone microstructure with that of non−mammalian cynodonts, extant monotremes, and placentals are also made, and significant differences in the rate of osteogenesis in the various groups are documented. Our findings suggest differences in the growth rate between the multituberculates and the Mesozoic eutherians, and moreover, both groups appear to have slower growth rates as compared to modern monotremes and placentals. Our re− sults further suggest that the determinate growth strategy typical of extant mammals evolved early in the evolution of the non−mammalian therapsids. We speculate that the sustained, uninterrupted bone formation among the multi− tuberculates may have been an adaptive attribute prior to the K−T event, but that the flexible growth strategy of the early eutherians was more advantageous thereafter.
Acta Palaeontologica Polonica, 1994
The orbital wall in Nemegtbaatar gohiensis and Chulsanbaatar vulgaris, from the Late Crrtaceous o... more The orbital wall in Nemegtbaatar gohiensis and Chulsanbaatar vulgaris, from the Late Crrtaceous of the Gobi Desert, Mongolia, comprises a small lacrimal anteriorly, large orbital process of the frontal dorsally, orbitosphenoid posteriorly and maxilla ventrally. Nemegtbaatar also posesses an orbital process of the palatine ventrally, not recognized in Chulsanbaatar. Large frontal sinuses of both taxa are interpreted as related to lack of the sagittal crest. Other anatomical characters found in this study, such as orbital process of the frontal, ossified turbinals, ossified ethmoid and vomer, frontal, sphenoidal and maxillary sinuses, and the presence of the orbital process of palatine in Nemegtbaatar suggest a close relationship of multituberculates to monotremes and therian mammals. By the new data obtained from the serial sections the diagnostic character: orbital process of the palatine absent in Multituberculata, is no longer valid. Ossified ethmoid and maxillary turbinals, chara...
PeerJ, 2020
Cryptoclidids are a major clade of plesiosauromorph plesiosaurians best known from the Middle—Lat... more Cryptoclidids are a major clade of plesiosauromorph plesiosaurians best known from the Middle—Late Jurassic, but little is known regarding their turnover into the Early Cretaceous. Of the known cryptoclidid genera, most preserve only a limited amount of cranial material and of theseCryptoclidus eurymerus, displays the most complete, but compressed cranium. Thus, the lack of knowledge of the cranial anatomy of this group may hinder the understanding of phylogenetic interrelationships, which are currently predominantly based on postcranial data. Here we present a nearly complete adult cryptoclidid specimen (PMO 224.248) representing a new genus and speciesOphthalmothule cryosteagen et sp. nov., from the latest Jurassic to earliest Cretaceous part of the Slottsmøya Member, of central Spitsbergen. The holotype material preserves a complete cranium, partial mandible, complete and articulated cervical, pectoral and anterior to middle dorsal series, along with the pectoral girdle and anter...
Norwegian Journal of Geology, 2018
A new specimen of Phalarodon from the Middle Triassic Botneheia Formation on Svalbard, although n... more A new specimen of Phalarodon from the Middle Triassic Botneheia Formation on Svalbard, although not complete, is well preserved with both cranial and postcranial elements. Uncompressed preservation of the rostrum reveals the dental groove divided by alveolar bone between the teeth. The right opisthotic has a thin and plate-like paroccipital process, a structure which has only been observed in Mixosaurus cornalianus among mixosaurids. The rare preservation of the atlas-axis complex, being nearly complete and articulated, is very similar to that of Phalarodon callawayi. The interclavicle, although not complete, is preserved with detailed structures which have previously not been described in Mixosauridae. Contrary to earlier studies, the shoulder girdle, with an articulated scapula and coracoid, reveals a coracoid facet on the scapula. Using comparative morphological and phylogenetic analyses, similarities between the new specimen and the known species of Mixosauridae are addressed. We assign the new specimen to Phalarodon fraasi. With its uncompressed preservation, the new specimen contributes to the knowledge of our morphology of the species. This study suggests a reassignment of the specimen PMO 219.250 to the genus Mixosaurus, and opens up for the possibility of Mixosaurus on Svalbard. This would imply a wider geographical distribution of the genus than previously recognised. Additionally, it would prove the coexistence of Mixosaurus and Phalarodon in a shared habitat at the same point in time, a hypothesis that is strengthened by the differences in dentition which reflects separate feeding habits, and thus different niches.
Norwegian Journal of Geology, 2018
Jaw elements of Omphalosaurus sp. are described from the Early Triassic (Spathian) of Marmierfjel... more Jaw elements of Omphalosaurus sp. are described from the Early Triassic (Spathian) of Marmierfjellet, Spitsbergen. The elements are from the Grippia and the Lower Saurian niveaus in the Vendomdalen Member of the Vikinghøgda Formation. In the Grippia niveau a bonebed was excavated in 2014-15 and a large number of ichthyopterygian elements were recovered. Together with the omphalosaurian jaw elements a collection of large vertebral centra were recognized as different from the smaller Grippia centra and more than 200 large vertebral centra are referred to Ichthyopterygia indet. and tentatively assigned to regions of the vertebral column. We refrain from further assignment due to the systematic position and the difficulty of defining criteria for recognizing postcranial elements of Omphalosaurus.
Norwegian Journal of Geology, 2018
Norwegian Journal of Geology, 2018
The palaeontology of the Lower to Middle Triassic succession in Spitsbergen has been studied for ... more The palaeontology of the Lower to Middle Triassic succession in Spitsbergen has been studied for more than a century and a half. Our ability to properly interpret the evolutionary and ecological implications of the faunas requires precise stratigraphic control that has only recently become available. Within such a detailed stratigraphic framework, the Spitsbergen fossil material promises to contribute to our understanding of the faunal recovery after the end-Permian mass extinction.
Acta Palaeontologica Polonica, 2019
Phylogenetic relationships within the important ichthyosaur family Ophthalmosauridae are not well... more Phylogenetic relationships within the important ichthyosaur family Ophthalmosauridae are not well established, and more specimens and characters, especially from the postcranial skeleton, are needed. Three ophthalmosaurid specimens from the Tithonian (Late Jurassic) of the Slottsmøya Member Lagerstätte on Spitsbergen, Svalbard, are described. Two of the specimens are new and are referred to Keilhauia sp. and Ophthalmosauridae indet. respectively, whereas the third specimen consists of previously undescribed basicranial elements from the holotype of Cryopterygius kristiansenae. The species was recently synonymized with the Russian Undorosaurus gorodischensis, but despite many similarities, we conclude that there are too many differences, for example in the shape of the stapedial head and the proximal head of the humerus; and too little overlap between specimens, to warrant synonymy on species level. A phylogenetic analysis of Ophthalmosauridae is conducted, including all Slottsmøya Member specimens and new characters. The two proposed ophthalmosaurid clades, Ophthalmosaurinae and Platypterygiinae, are retrieved under some circumstances, but with little support. The synonymy of three taxa from the Slottsmøya Member Lagerstätte with Arthropterygius is not supported by the present evidence.
PeerJ, 2018
The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marin... more The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marine reptiles, including four named taxa of ophthalmosaurid ichthyosaurs. One of these, , is based on the single holotype specimen (SVB 1451) with an incomplete skull. A newly discovered specimen (PMO 222.669) with a disarticulated but largely complete skull and anterior postcranium is described, which considerably expands our knowledge of this taxon. Two additional new ophthalmosaurid specimens with pectoral girdles from the same member are described. The taxonomic utility of the ophthalmosaurid pectoral girdle is contentious, and an assessment of seven pectoral girdles from the Slottsmøya Member provides a basis for addressing this question via a 2D landmark principal component analysis of baracromian coracoids. The analysis reveals a taxonomic signal in the coracoids but also highlights the degree of individual variation. Commonly used phylogenetic characters do not fully encapsulate the...
Journal of Vertebrate Paleontology, 2017
Colymbosaurus is a genus of long-necked plesiosaurian represented by two valid species: C. megade... more Colymbosaurus is a genus of long-necked plesiosaurian represented by two valid species: C. megadeirus from the Upper Kimmeridge Clay Formation (Kimmeridgian-Tithonian) of the United Kingdom and C. svalbardensis from the Slottsmøya Member of the Agardhfjellet Formation (Tithonian-Berriasian) of Svalbard, Norway. Due to the lack of complete and articulated skeletons and a near absence of cranial material, Colymbosaurus has been problematic to characterize morphologically. Here, we describe and conduct a phylogenetic analysis on an informative new specimen referable to C. svalbardensis from the Slottsmøya Member, preserving a large portion of the axial and appendicular skeleton. The new material contributes important new osteological data for the species and together with an extensive examination of congeners in British museums, clarifies the diagnostic characters of the genus. We provide two new diagnostic characters of the epipodials for the genus and reevaluate the utility of an anteroposteriorly oriented bisecting ridge on the distal end of the propodials. We also present two new diagnostic features for C. svalbardensis regarding the neural canal and femoral morphology. A phylogenetic analysis recovers a monophyletic and well-supported Colymbosaurus. The new specimen of C. svalbardensis confirms that this species is not synonymous with other described Slottsmøya Member plesiosauroids, demonstrating considerable diversity of the clade at high latitudes close to the Jurassic-Cretaceous boundary.
PLOS ONE, 2017
In spite of a fossil record spanning over 150 million years, pelvic girdle evolution in Ichthyopt... more In spite of a fossil record spanning over 150 million years, pelvic girdle evolution in Ichthyopterygia is poorly known. Here, we examine pelvic girdle size relationships using quantitative methods and new ophthalmosaurid material from the Slottsmøya Member Lagerstä tte of Svalbard, Norway. One of these new specimens, which preserves the most complete ichthyosaur pelvic girdle from the Cretaceous, is described herein as a new taxon, Keilhauia nui gen. et sp. nov. It represents the most complete Berriasian ichthyosaur known and the youngest yet described from the Slottsmøya Member. It is diagnosed on the basis of two autapomorphies from the pelvic girdle, including an ilium that is anteroposteriorly expanded at its dorsal end and an ischiopubis that is shorter or subequal in length to the femur, as well as a unique character combination. The Slottsmøya Member Lagerstä tte ichthyosaurs are significant in that they represent a diverse assemblage of ophthalmosaurids that existed immediately preceding and across the Jurassic-Cretaceous boundary. They also exhibit considerable variation in pelvic girdle morphology, and expand the known range in size variation of pelvic girdle elements in the clade.
Geological Society, London, Special Publications, 2016
The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last ... more The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last 15 years have witnessed an explosive advance in research, most notably on the richly fossiliferous Triassic (Olenekian–Carnian) and Jurassic (Tithonian)Lagerstättenof the Norwegian Arctic Svalbard archipelago, Late Cretaceous (Campanian) Kristianstad Basin and Vomb Trough of Skåne in southern Sweden, and the UNESCO heritage site at Stevns Klint in Denmark – the latter constituting one of the most complete Cretaceous–Palaeogene (Maastrichtian–Danian) boundary sections known globally. Other internationally significant deposits include earliest (Induan) and latest Triassic (Norian–Rhaetian) strata from the Danish autonomous territory of Greenland, and the Early Jurassic (Sinemurian–Pliensbachian) to Early Cretaceous (Berriasian) rocks of southern Sweden and the Danish Baltic island of Bornholm, respectively. Marine palaeocommunities are especially well documented, and comprise prolific bent...
PeerJ, Oct 12, 2018
The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marin... more The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marine reptiles, including four named taxa of ophthalmosaurid ichthyosaurs. One of these, Palvennia hoybergeti, is based on the single holotype specimen (SVB 1451) with an incomplete skull. A newly discovered specimen (PMO 222.669) with a disarticulated but largely complete skull and anterior postcranium is described, which considerably expands our knowledge of this taxon. Two additional new ophthalmosaurid specimens with pectoral girdles from the same member are described. The taxonomic utility of the ophthalmosaurid pectoral girdle is contentious, and an assessment of seven pectoral girdles from the Slottsmøya Member provides a basis for addressing this question via a 2D landmark principal component analysis of baracromian coracoids. The analysis reveals a taxonomic signal in the coracoids but also highlights the degree of individual variation. Commonly used phylogenetic characters do not fully encapsulate the degree of variation seen in coracoids and in some cases combine analogous features.
Collections, Apr 21, 2023
Acta Palaeontologica Polonica, 1997
Mongolian Late Cretaceous multituberculates (except Buginbaatar) form a monophyletic group for wh... more Mongolian Late Cretaceous multituberculates (except Buginbaatar) form a monophyletic group for which the suborder Djadochtatheria is proposed. Synapomorphies of Djadochtatheria are: large frontals pointed anteriorly and deeply inserted between the nasals, U-shaped fronto-parietal suture, no frontal-maxilla contact, and edge between palatal and lateral walls of premaxilla. Large, rectangular facial surface of the lacrimal exposed on the dorsal side of the cranial roof is present in all djadochtatherians, but may be a plesiom\\orphic feature. It is also possible that in djadochtatherians the postglenoid part of the braincase is relatively longer than in other multituberculates. Djadochtatherims have an arcuate p4 (secondarily subtrapezoidal in Catopsbaatar) that does not protrude dorsally over the level of the molars (shared with Eucosmodontidae), I3 placed on the palatal part of the premaxilla (shared with the eucosmodontid Stygimys and the cimolomyid Meniscoessus). The small number of cusps on the upper and lower molars and no more than nine ridges on p4 are possibly plesiomorphies for Djadochtatheria. The djadochtatherian Nessovbaatar multicostatus gen. et sp. n., family incertae sedis from the Barun Goyot Formation is proposed. New specimens of the djadochtatherian genera Kryptobaatar, ?Djadochtatherium, and Kamptobaatar are described and revised diagnoses of these taxa and Sloanbaatar are given. A cladistic analysis of Mongolian Late Cretaceous multituberculates (MLCM), using Pee-Wee and NONA programs and employing 43 dental and cranial characters, 11 MLCM taxa, five selected Late Cretaceous or Paleocene multituberculate genera from other regions, and a hypothetical ancestor based on the structure of Plagiaulacoidea, is performed. The Pee-Wee program yielded two equally fit trees that confirm the monophyly of MLCM excluding Buginbaatal: Kryptobaatar, Djadochtatherium, Catopsbaatar, and Tombaatar form a clade, for which the family Djadochtatheriidae is proposed. Chulsanbaataris the sister taxon of this clade. Bulganbaatar and Nemegtbaatar are the sister group of all other djadochtatherians. Kamptobaatar, Sloanbaatar, and Nessovbaatar form a separate clade in the Pee-Wee tree. The NONAprogram yielded thirty equally parsimonious trees and a strict consensus tree with a poor resolution.
Acta Palaeontologica Polonica
The marine Middle Triassic sediments of Svalbard are rich in fossiliferous material and are parti... more The marine Middle Triassic sediments of Svalbard are rich in fossiliferous material and are particularly well-known for marine reptile fossils. Here, we present a new specimen of the small-bodied mixosaurid ichthyosaur Phalarodon fraasi from the Botneheia Formation. PMO 235.393 is unusual in being the first three-dimensional mixosaurid skull recovered from this formation, allowing us to use computed tomography to reconstruct the obscured right side of the cranium, resulting in the first 3D model available for a mixosaurid ichthyosaur. Although separated into different slabs, the specimen preserves most of the dermatocranium as well as some partial post-cranial elements. In particular, the rostrum, external naris, dentition, quadrate and sclerotic ring are well-preserved. This methodology gave new insights into the adaptations this taxon has to durophagy, as well as a detailed look at the heterodont dentition present in PMO 235.393. After comparing with other Phalarodon specimens, it was clear that the maxillary heterodonty of this genus is a synapomorphy. As such this was added as a new character in our phylogenetic analysis, supporting the separation of Phalarodon and Mixosaurus.
The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic ... more The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic Norway) is presented and described. The specimen, a femur, was collected from the Zillerberget member of the Carolinefjellet Formation at Schönrockfjellet in 1962 and was recently re-discovered. The bone is referred to ?Avialae based on a combination of characters, including extreme thinness of the cortex, a well-developed head, and the presence of a patellar sulcus. From biostratigraphic analysis, it is demonstrated that the bone comes from the lower part of the middle Albian. This find is important because the Early Cretaceous fossil record of Avialae remains poorly documented in most parts of the World and is non-existent in Arctic strata. A general overview of the geology and stratigraphy of the Lower Cretaceous in Spitsbergen is presented in order to provide context for the fossil occurrence, with a particular focus on the Aptian and Albian sedimentary system and with the first-ever report on the entire stratigraphy on the east face of Schönrockfjellet.
Norwegian Journal of Geology, 2018
The Agardhfjellet Formation (Middle Jurassic to lowermost Cretaceous) of Svalbard (Norwegian Arct... more The Agardhfjellet Formation (Middle Jurassic to lowermost Cretaceous) of Svalbard (Norwegian Arctic) is well known for its abundant and unique marine reptile fauna, of ichthyosaurs and plesiosaurs. In an attempt to reconstruct the palaeoecology and palaeoenvironment of the Agardhfjellet Formation, a study of the invertebrate fauna, geochemistry and stratigraphy was conducted. During this study numerous small vertebrate fossils were encountered. Only a few reports of Jurassic teleost from the Arctic were known previously, from the Agardhfjellet Formation on Svenskøya, Kong Karls Land, described as Leptolepis nathorsti, and at Lardyfjellet, East Spitsbergen. We describe more teleost material from the Kimmeridgian and Volgian of the Agardhfjellet Formation in central Spitsbergen and assign a new age, Kimmeridgian, to the original material. This new material also provides more information on the palaeoecology of the Jurassic of Svalbard, showing that fish were probably common in the pelagic fauna of central Spitsbergen together with the better known cephalopods, and could have been important elements of the diet of the marine reptiles.
We present results of the first studies of the bone microstructure of early mammals, based on the... more We present results of the first studies of the bone microstructure of early mammals, based on the Early Jurassic Morganucodon, the Late Cretaceous multituberculates, Kryptobaatar and Nemegtbaatar, and the Late Cretaceous eu− therians Zalambdalestes and Barunlestes. Our results show that the two eutherian taxa grew relatively slowly with pe− riodic pauses in growth indicated by the presence of rest lines, while the multituberculates and Morganucodon had a faster rate of bone formation that suggests an overall rapid growth rate that slowed down later in ontogeny. Compari− sons of the early mammalian bone microstructure with that of non−mammalian cynodonts, extant monotremes, and placentals are also made, and significant differences in the rate of osteogenesis in the various groups are documented. Our findings suggest differences in the growth rate between the multituberculates and the Mesozoic eutherians, and moreover, both groups appear to have slower growth rates as compared to modern monotremes and placentals. Our re− sults further suggest that the determinate growth strategy typical of extant mammals evolved early in the evolution of the non−mammalian therapsids. We speculate that the sustained, uninterrupted bone formation among the multi− tuberculates may have been an adaptive attribute prior to the K−T event, but that the flexible growth strategy of the early eutherians was more advantageous thereafter.
Acta Palaeontologica Polonica, 1994
The orbital wall in Nemegtbaatar gohiensis and Chulsanbaatar vulgaris, from the Late Crrtaceous o... more The orbital wall in Nemegtbaatar gohiensis and Chulsanbaatar vulgaris, from the Late Crrtaceous of the Gobi Desert, Mongolia, comprises a small lacrimal anteriorly, large orbital process of the frontal dorsally, orbitosphenoid posteriorly and maxilla ventrally. Nemegtbaatar also posesses an orbital process of the palatine ventrally, not recognized in Chulsanbaatar. Large frontal sinuses of both taxa are interpreted as related to lack of the sagittal crest. Other anatomical characters found in this study, such as orbital process of the frontal, ossified turbinals, ossified ethmoid and vomer, frontal, sphenoidal and maxillary sinuses, and the presence of the orbital process of palatine in Nemegtbaatar suggest a close relationship of multituberculates to monotremes and therian mammals. By the new data obtained from the serial sections the diagnostic character: orbital process of the palatine absent in Multituberculata, is no longer valid. Ossified ethmoid and maxillary turbinals, chara...
PeerJ, 2020
Cryptoclidids are a major clade of plesiosauromorph plesiosaurians best known from the Middle—Lat... more Cryptoclidids are a major clade of plesiosauromorph plesiosaurians best known from the Middle—Late Jurassic, but little is known regarding their turnover into the Early Cretaceous. Of the known cryptoclidid genera, most preserve only a limited amount of cranial material and of theseCryptoclidus eurymerus, displays the most complete, but compressed cranium. Thus, the lack of knowledge of the cranial anatomy of this group may hinder the understanding of phylogenetic interrelationships, which are currently predominantly based on postcranial data. Here we present a nearly complete adult cryptoclidid specimen (PMO 224.248) representing a new genus and speciesOphthalmothule cryosteagen et sp. nov., from the latest Jurassic to earliest Cretaceous part of the Slottsmøya Member, of central Spitsbergen. The holotype material preserves a complete cranium, partial mandible, complete and articulated cervical, pectoral and anterior to middle dorsal series, along with the pectoral girdle and anter...
Norwegian Journal of Geology, 2018
A new specimen of Phalarodon from the Middle Triassic Botneheia Formation on Svalbard, although n... more A new specimen of Phalarodon from the Middle Triassic Botneheia Formation on Svalbard, although not complete, is well preserved with both cranial and postcranial elements. Uncompressed preservation of the rostrum reveals the dental groove divided by alveolar bone between the teeth. The right opisthotic has a thin and plate-like paroccipital process, a structure which has only been observed in Mixosaurus cornalianus among mixosaurids. The rare preservation of the atlas-axis complex, being nearly complete and articulated, is very similar to that of Phalarodon callawayi. The interclavicle, although not complete, is preserved with detailed structures which have previously not been described in Mixosauridae. Contrary to earlier studies, the shoulder girdle, with an articulated scapula and coracoid, reveals a coracoid facet on the scapula. Using comparative morphological and phylogenetic analyses, similarities between the new specimen and the known species of Mixosauridae are addressed. We assign the new specimen to Phalarodon fraasi. With its uncompressed preservation, the new specimen contributes to the knowledge of our morphology of the species. This study suggests a reassignment of the specimen PMO 219.250 to the genus Mixosaurus, and opens up for the possibility of Mixosaurus on Svalbard. This would imply a wider geographical distribution of the genus than previously recognised. Additionally, it would prove the coexistence of Mixosaurus and Phalarodon in a shared habitat at the same point in time, a hypothesis that is strengthened by the differences in dentition which reflects separate feeding habits, and thus different niches.
Norwegian Journal of Geology, 2018
Jaw elements of Omphalosaurus sp. are described from the Early Triassic (Spathian) of Marmierfjel... more Jaw elements of Omphalosaurus sp. are described from the Early Triassic (Spathian) of Marmierfjellet, Spitsbergen. The elements are from the Grippia and the Lower Saurian niveaus in the Vendomdalen Member of the Vikinghøgda Formation. In the Grippia niveau a bonebed was excavated in 2014-15 and a large number of ichthyopterygian elements were recovered. Together with the omphalosaurian jaw elements a collection of large vertebral centra were recognized as different from the smaller Grippia centra and more than 200 large vertebral centra are referred to Ichthyopterygia indet. and tentatively assigned to regions of the vertebral column. We refrain from further assignment due to the systematic position and the difficulty of defining criteria for recognizing postcranial elements of Omphalosaurus.
Norwegian Journal of Geology, 2018
Norwegian Journal of Geology, 2018
The palaeontology of the Lower to Middle Triassic succession in Spitsbergen has been studied for ... more The palaeontology of the Lower to Middle Triassic succession in Spitsbergen has been studied for more than a century and a half. Our ability to properly interpret the evolutionary and ecological implications of the faunas requires precise stratigraphic control that has only recently become available. Within such a detailed stratigraphic framework, the Spitsbergen fossil material promises to contribute to our understanding of the faunal recovery after the end-Permian mass extinction.
Acta Palaeontologica Polonica, 2019
Phylogenetic relationships within the important ichthyosaur family Ophthalmosauridae are not well... more Phylogenetic relationships within the important ichthyosaur family Ophthalmosauridae are not well established, and more specimens and characters, especially from the postcranial skeleton, are needed. Three ophthalmosaurid specimens from the Tithonian (Late Jurassic) of the Slottsmøya Member Lagerstätte on Spitsbergen, Svalbard, are described. Two of the specimens are new and are referred to Keilhauia sp. and Ophthalmosauridae indet. respectively, whereas the third specimen consists of previously undescribed basicranial elements from the holotype of Cryopterygius kristiansenae. The species was recently synonymized with the Russian Undorosaurus gorodischensis, but despite many similarities, we conclude that there are too many differences, for example in the shape of the stapedial head and the proximal head of the humerus; and too little overlap between specimens, to warrant synonymy on species level. A phylogenetic analysis of Ophthalmosauridae is conducted, including all Slottsmøya Member specimens and new characters. The two proposed ophthalmosaurid clades, Ophthalmosaurinae and Platypterygiinae, are retrieved under some circumstances, but with little support. The synonymy of three taxa from the Slottsmøya Member Lagerstätte with Arthropterygius is not supported by the present evidence.
PeerJ, 2018
The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marin... more The Late Jurassic Slottsmøya Member Lagerstätte on Spitsbergen preserves a diverse array of marine reptiles, including four named taxa of ophthalmosaurid ichthyosaurs. One of these, , is based on the single holotype specimen (SVB 1451) with an incomplete skull. A newly discovered specimen (PMO 222.669) with a disarticulated but largely complete skull and anterior postcranium is described, which considerably expands our knowledge of this taxon. Two additional new ophthalmosaurid specimens with pectoral girdles from the same member are described. The taxonomic utility of the ophthalmosaurid pectoral girdle is contentious, and an assessment of seven pectoral girdles from the Slottsmøya Member provides a basis for addressing this question via a 2D landmark principal component analysis of baracromian coracoids. The analysis reveals a taxonomic signal in the coracoids but also highlights the degree of individual variation. Commonly used phylogenetic characters do not fully encapsulate the...
Journal of Vertebrate Paleontology, 2017
Colymbosaurus is a genus of long-necked plesiosaurian represented by two valid species: C. megade... more Colymbosaurus is a genus of long-necked plesiosaurian represented by two valid species: C. megadeirus from the Upper Kimmeridge Clay Formation (Kimmeridgian-Tithonian) of the United Kingdom and C. svalbardensis from the Slottsmøya Member of the Agardhfjellet Formation (Tithonian-Berriasian) of Svalbard, Norway. Due to the lack of complete and articulated skeletons and a near absence of cranial material, Colymbosaurus has been problematic to characterize morphologically. Here, we describe and conduct a phylogenetic analysis on an informative new specimen referable to C. svalbardensis from the Slottsmøya Member, preserving a large portion of the axial and appendicular skeleton. The new material contributes important new osteological data for the species and together with an extensive examination of congeners in British museums, clarifies the diagnostic characters of the genus. We provide two new diagnostic characters of the epipodials for the genus and reevaluate the utility of an anteroposteriorly oriented bisecting ridge on the distal end of the propodials. We also present two new diagnostic features for C. svalbardensis regarding the neural canal and femoral morphology. A phylogenetic analysis recovers a monophyletic and well-supported Colymbosaurus. The new specimen of C. svalbardensis confirms that this species is not synonymous with other described Slottsmøya Member plesiosauroids, demonstrating considerable diversity of the clade at high latitudes close to the Jurassic-Cretaceous boundary.
PLOS ONE, 2017
In spite of a fossil record spanning over 150 million years, pelvic girdle evolution in Ichthyopt... more In spite of a fossil record spanning over 150 million years, pelvic girdle evolution in Ichthyopterygia is poorly known. Here, we examine pelvic girdle size relationships using quantitative methods and new ophthalmosaurid material from the Slottsmøya Member Lagerstä tte of Svalbard, Norway. One of these new specimens, which preserves the most complete ichthyosaur pelvic girdle from the Cretaceous, is described herein as a new taxon, Keilhauia nui gen. et sp. nov. It represents the most complete Berriasian ichthyosaur known and the youngest yet described from the Slottsmøya Member. It is diagnosed on the basis of two autapomorphies from the pelvic girdle, including an ilium that is anteroposteriorly expanded at its dorsal end and an ischiopubis that is shorter or subequal in length to the femur, as well as a unique character combination. The Slottsmøya Member Lagerstä tte ichthyosaurs are significant in that they represent a diverse assemblage of ophthalmosaurids that existed immediately preceding and across the Jurassic-Cretaceous boundary. They also exhibit considerable variation in pelvic girdle morphology, and expand the known range in size variation of pelvic girdle elements in the clade.
Geological Society, London, Special Publications, 2016
The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last ... more The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last 15 years have witnessed an explosive advance in research, most notably on the richly fossiliferous Triassic (Olenekian–Carnian) and Jurassic (Tithonian)Lagerstättenof the Norwegian Arctic Svalbard archipelago, Late Cretaceous (Campanian) Kristianstad Basin and Vomb Trough of Skåne in southern Sweden, and the UNESCO heritage site at Stevns Klint in Denmark – the latter constituting one of the most complete Cretaceous–Palaeogene (Maastrichtian–Danian) boundary sections known globally. Other internationally significant deposits include earliest (Induan) and latest Triassic (Norian–Rhaetian) strata from the Danish autonomous territory of Greenland, and the Early Jurassic (Sinemurian–Pliensbachian) to Early Cretaceous (Berriasian) rocks of southern Sweden and the Danish Baltic island of Bornholm, respectively. Marine palaeocommunities are especially well documented, and comprise prolific bent...
English translation of "Borgias forbudte bok", 2024
I have long wanted to write a humorous and nerdy book on the early history of geology based on ex... more I have long wanted to write a humorous and nerdy book on the early history of geology based on examples from my own book collection. When I got my hands a book that I could use to bring this history to life, my mind was set. I contacted Torstein Helleve, who has co-written several children's books with me. He joined me and is a significant contributor to this book, even though it is written in the first person.
Published in Norwegian in 2021 by CappelenDamm, all right to the English edition transferred to the authors in 2023.
The book printed in Norwegian: Hurum, J.H. and Helleve, T. 2021: Borgias forbudte bok - steingale samlere og pillråtne paver. CappelenDamm ISBN 9788202660789.
DGB, 2015
Denne boken er en kort historie om de geologiske og paleontologiske samlingene ved Naturhistorisk... more Denne boken er en kort historie om de geologiske og paleontologiske
samlingene ved Naturhistorisk museum, Universitetet i Oslo.
Hovedfokuset i boken er på vakre fossiler og krystaller. Disse vil alle bli vist når vi åpner det nye museet våren 2022.
Utgitt med støtte fra museets venneforening PalVenn.
Denne pdf er en lavoppløslig versjon av boken som kan kjøpes i museumsbutikken eller hos palvenn.no.
Hammer, Øyvind. 2015: Fossiler og mineraler. Høydepunkter fra samlingene på Naturhistorisk museum... more Hammer, Øyvind. 2015: Fossiler og mineraler. Høydepunkter fra samlingene på Naturhistorisk museum.. : Kunstbokforlaget DGB (ISBN 7029660051309) 168 s.
Hurum, Jørn Harald; Helleve, Torstein. 2012: Monsterøglene på Svalbard. Cappelen Damm AS (ISBN 97... more Hurum, Jørn Harald; Helleve, Torstein. 2012: Monsterøglene på Svalbard. Cappelen Damm AS (ISBN 978-82-02-37565-2) 84 s.
Sabeltannmysteriet. Aschehoug & Co (ISBN xxx) 16 s.
Hvem drepte ammonitten?. Aschehoug & Co (ISBN xxx) 16 s.
Hurum & Frøyland (eds) 2004 (komplett)
Frøyland, M., Frøyland, S.L. & Hurum, J.H. 2011. Stein og fossiler i barnehagen. In: Forskerfrøboka. Barn og natur. Bergen: Fagbokforlaget Vigmostad & Bjørke AS. 225-246., 2011
Steiner finnes overalt, de er lett tilgjengelige for alle, og de fleste barn fyller lommene sine ... more Steiner finnes overalt, de er lett tilgjengelige for alle, og de fleste barn fyller lommene sine med dem. Derfor er stein et tema for barnehagene. Utfordringen er at få av de voksne har grunnleggende kunnskap om stein. Dette ønsket vi å finne en løsning på, og her er resultatet av forsøk~t. I barnehagen hvor forsøket ble gjennomført, hadde barna lenge lekt lavalek. Det var et godt utgangspunkt for å starte et tema om stein og fossiler i barnehagen.
Mesozoic Biotas of Scandinavia & its Arctic Territories, 2016
The Mesozoic (252-66 MYA) was arguably one of the most spectacular intervals of biotic evolution ... more The Mesozoic (252-66 MYA) was arguably one of the most spectacular intervals of biotic evolution in Earth History. It witnessed the explosive radiation of modern faunal and floral biodiversity, and culminated in one of the most cataclysmic extinction events recognised from the fossil record. Much of our present understanding of the Mesozoic world has derived from the long history of palaeontological research in Europe, and yet, many key biotas and bioevents remain comparatively under explored. This commissioned volume of The Geological Society of London Special Publications Series therefore aims to showcase one of the most enigmatic geographical regions - Scandinavia and its Arctic Territories of Greenland and Svalbard - which in recent years have witnessed numerous significant discoveries and provided important insights into Mesozoic high-latitude ecosystems and environments. A core of papers covering these latest advances, augmented with topical articles contributed by leading specialists in the field, will make this volume a landmark compilation presenting work on a broad spectrum of multidisciplinary themes.
The explosion of new discoveries over the last few decades, coupled with insights from rapidly advancing quantitative methodologies, has highlighted the Scandinavian territories as a critical region for unraveling mid-high latitude biotic evolution during the Mesozoic. Global lineage cladogenesis, major biogeographical dispersals, and significant multi-taxon extinction events have been linked in with large-scale environmental peturbations otherwise not well represented in the rock record from elsewhere. Despite this, the relatively youthful history of intensive Mesozoic-focused research in Scandinavia has meant that substantial advancements are only now coming to the fore. In particular, growing evidence for significant floral successions, and seminal radiations of faunas at the high latitude extremities of Pangaea, has emphasized the primary role of the northern polar regions as an evolutionary centre for past biotic dispersals. This theme will be emphasized in contributions to this volume, as will the intrinsic influences affecting macroevolutionary patterns in significant model lineages.
Outreach is something few scientists ever bother to do. If a researcher do outreach at all it is ... more Outreach is something few scientists ever bother to do. If a researcher do outreach at all it is often only to impress his colleagues, not to tell the public about his research.
Why should we do outreach? It takes time away from research, you have to answer questions from a lay audience, and you have to stop using your tribal language. The common term for outreach in many institutions are “vulgarization” and “dumbing down”. We all know researchers that appeared in media and are later called “media horny”.
On the institutional level outreach are praised with empty words in every annual report or speech by the institutional leaders. It is politically correct to mention the magic word “outreach – formidling” but when push comes to show no institution takes it seriously and backs it with a proper amount of money or approval.
Today scientific publications are rewarded in many institutions, but few have any form of rewards for the scientists doing outreach. Outreach takes time just like research and is a skill that needs to be trained. If institutions want to praise scientists doing outreach they should take them seriously, if not they should take the consequence and declare their institution outreach free and ban the use of paid time to do it.
But why do some of us do outreach anyway? My rewards are the meetings with enthusiastic children, getting letters and e-mails from all over the World and see schools do projects generated from my research. Other smaller but important byproducts of this is the branding of me and my science; public awareness of how science works; being able to influence political decisions in publishing policy (Open access); attract sponsors to projects; and trying to change the attitude in academia towards outreach.
I do not believe that every scientist should do outreach, many are not shaped for it. They can be eminent researchers anyway and should be praised for their work, and left alone. But if any institution wants to take outreach seriously a few positions in a project should be hired not only on the amount of scientific publications but also partly on the outreach documented in a CV.