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Mosasaur bite marks on a plesiosaur propodial from the Campanian (Late Cretaceous) of southern Sweden

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Abstract

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.

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... Today, these palaeoenvironments are represented by several well-known fossil deposits, such as those exposed at Ignaberga, Ullstorp, Ivö Klack and Å sen ( Fig. 1) (Bergström & Sundquist 1978;Erlström & Gabrielson 1992). The successions at Å sen and Ivö Klack are especially rich in vertebrate remains, including sharks, rays, actinopterygian fishes, mosasaurs, plesiosaurs, marine and freshwater turtles, aquatic birds, and rare non-avian dinosaur bones (Einarsson et al. 2010;Sørensen et al. 2013;Bazzi et al. 2015;Poropat et al. 2015;Siversson et al. 2015). Coeval invertebrate assemblages comprise bivalves, cephalopods, gastropods, brachiopods, bryozoans and echinoderms, mainly represented by sea-urchin spines (Erlström & Gabrielson 1992;Surlyk & Sørensen 2010;Sørensen & Surlyk 2011;Sørensen et al. 2013). ...
... Å sen is situated a few kilometres north of the small town of Bromölla in the Kristianstad Basin (568 08 ′ 56.1 ′′ N, 148 29 ′ 56.0 ′′ E: Fig. 1). The site is currently a municipal landfill and recycling centre (Einarsson et al. 2010;Sørensen et al. 2013). The strata at Å sen have been correlated with the mid-Campanian informally termed Belemnellocamax mammilatus and Belemnellocamax balsvikensis biozones ( Fig. 2) (Lindgren & Siverson 2002). ...
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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 A ˚ sen 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 A ˚ sen that was rich in carbonate-cemented nodules.
... Stratigraphy and geological setting Christensen (1975, 1998), Bergström & Sundquist (1978, Lidmar-Bergström (1982) and Erlström & Gabrielson (1986, 1992 provided lithostratigraphical syntheses of the Kristianstad Basin. In brief summation, the sequences commence with a Precambrian crystalline basement that is weathered into a deeply uneven surface topography (Bergström & Sundquist 1978;Lidmar-Bergström 1982), and faulted by two half-graben intercepted in the south by the Nävlingåsen and Linderödåsen horst ridges (Lindgren et al. 2007;Einarsson et al. 2010). This in turn is overlain by up to 200 m of Late Cretaceous detrital carbonates, sands and silt ) that were deposited along the NE margin of a warm temperate to subtropical chalk sea (Siverson 1992a;Surlyk 1997;Sørensen et al. 2013). ...
... Furthermore, the prevalence of more durable diagnostic elements accords with the predominance of chondrichthyan (Siverson 1992a(Siverson , 1993 and marine amniote taxa (e.g. Lindgren & Siverson 2002;Lindgren 2004Lindgren , 2005Einarsson et al. 2010), which are readily identifiable from robust teeth and large bones, and infer a major biotic turnover across the lower -upper Campanian boundary (corresponding with the B. mammillatus to B. balsvikensis biozone transition: Lindgren 2004). Unfortunately, a dearth of fossils from the B. balsvikensis biozone (Fig. 6) precludes independent confirmation of this faunal perturbation, yet it is notable that a substantial facies shift also occurs across the biostratigraphical boundary. ...
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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.
... The mosasaur fauna was listed once again by Russell (1967). More recently, shark teeth have been either listed or described by Bergström and Sundquist (1978), Bergström (1983), Siverson (1992aSiverson ( ,b, 1993Siverson ( , 1995 and Rees (1999), while teeth and bones of mosasaurs were described by Lindgren and Siverson (2002, 2005 and Lindgren (2004Lindgren ( , 2005a, mosasaur bite marks on a plesiosaur propodial by Einarsson et al. (2010), bones of aquatic birds by Rees and Lindgren (2005), a carapace fragment of a soft-shelled turtle by Scheyer et al. (2012), dental and vertebral elements of dinosaurs by Lindgren et al. (2007), and vertebrate coprolites by Eriksson et al. (2011). ...
... Teeth of large nektonic sharks have been found embedded in partially digested mosasaur bones from the Western Interior Seaway of North America, suggesting that they were able to feed or scavenge on these large reptiles (Everhart et al., 1995;Shimada, 1997). Bite marks and scratches inflicted by sharks are also relatively common on reptile bones from the Kristianstad Basin (Einarsson et al., 2010). ...
... Frey et al. 2002), plesiosaurs (e.g. Barnes and Hillier 2010;Einarsson et al. 2010;Shimada et al. 2010), and mosasaurs (e.g. Shimada 1997;Everhart 2004Everhart , 2008Lingham-Soliar 2004;Rothschild et al. 2005). ...
... Shimada 1997) or parallel sets of cuts (e.g. Einarsson et al. 2010); these are not unlike the furrows evident on the jaw of SAM P14508 but bear little similarity to the circular gouge on the left dentary. ...
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Healed bite marks on a Cretaceous ichthyosaur. Acta Palaeontologica Polonica 5X (X): xxx-xxx. doi:10.4202/app.2010.0117 Reports of pathological ichthyosaur fossils are very rare. The identification of a series of healed cuts and an associated gouge on the lower jaw of an adult (ca 5 metres body length) Platypterygius specimen from the Lower Cretaceous of Australia is therefore significant, because it constitutes direct evidence of bite force trauma sustained during the life of the animal. Based on the close spacing and non-lethal facial positioning of the wounds, they were probably not inflicted by a predator. Alternative explanations might include an accidental aggressive encounter with another large vertebrate, or perhaps an intraspecific interaction such as during courtship or combat over food, mates or territory.
... NRM hosts abundant collections from this area dominated by invertebrate fossils, such as bivalves, belemnites, echinoderms, corals, sponges and crustaceans, much of them collected by Richard Hägg in the early 1900s when kaolinite was quarried at Ivö and other localities . Vertebrate fossils in the collections are chiefly represented by mosasaur and plesiosaur teeth, vertebrae and paddles, shark teeth, and turtle, bird and fish remains (Einarsson et al. 2010). ...
... Despite recognition of bone pathologies of Mesozoic marine reptiles in general and plesiosaurs in particular, since the 1870s (Mudge, 1878), reports of infectious diseases area still comparatively very scarce (Lingham-Soliar, 2004;Schulp et al., 2006;Surmik et al., 2017). Pathologies previously reported include septic necrosis, avascular necrosis, Schmorl's nodules [subsequently recognized as subchondral erosions of spondyloarthropathy, since plesiosaurs and mosasaurs have synovial joints, not disks (Rothschild et al., 2020)], osteoarthritis, vertebral fusions (Hopley, 2001;Rothschild and Martin, 1987;Rothschild and Storrs, 2003;Sassoon, 2019;Sassoon et al., 2012;Surmik et al., 2017) and numerous with tooth marks (Thulborn and Turner, 1993;Einarsson et al., 2010;Shimada et al., 2010;Rothschild et al., 2018). The vertebra described herein shows an elliptical subchondral erosion with new bone formation and adjacent slight filigree reaction as well as a groove just ventral to the articular surface and a central lytic area with weakened and collapsed trabecular bone. ...
Article
Paleopathological studies have been used to understand the history of injury and disease in extinct populations, their putative causes and, on this basis, to infer paleoecology and behavioral aspects. The most common pathologies reported in the zoological/paleontological record are traumatic injuries, post-traumatic malformations, inflammatory arthritis, infection and congenital defects. Although pathologies in plesiosaurs are recognized since the 1870s, reports of infectious disease are comparatively scarce. Here we report the pathological cervical vertebra of a plesiosaur recovered from the Upper Cretaceous of Argentina. The anterior external surface shows an elliptical, subchondral erosion with new bone formation and slight adjacent filigree reaction. The right anteroventral surface of the centrum bears erosive processes with bone reaction and alterations that have the appearance produced by space-occupied masses. On the left anteroventral surface of the centrum, there are abnormal vascular channels, associated with a groove just ventral to the articular surface. The combination of these features indicates that the pathological aspect of the vertebra is due to an infection. The pattern of bone abnormalities is compatible with those described in Pleistocene mammals affected by the granulomatous tuberculosis infection and with the abnormal ribs and cervical vertebrae of an eosauropterygian from the Triassic. The case reported herein represents the first record of tuberculosis-like infection in a plesiosaur. As the vertebra was not part of an associated skeleton, we cannot infer if the cause of death could have been related to the compromised hunting ability (due to limited neck mobility) or the result of infection-related organ failure.
... Late Cretaceous and early Cenozoic (Danian) strata in southern Sweden (Skåne) yield a rich record of fossil vertebrates including chondrichthyans, actinopterygians, turtles, plesiosaurs, mosasaurs, crocodylians, hesperornithid birds, and nonavian dinosaurs (e.g., Lindgren 2004;Rees & Lindgren 2005;Einarsson et al. 2010;Scheyer et al. 2012;Sørensen et al. 2013;Siverson et al. 2015;Bazzi et al. 2016;Kear et al. 2016). In contrast to the wealth of these Late Cretaceous and Danian vertebrate remains, only a single bone fragment, possibly representing a coelacanthid fish, has been described so far from the Scanian Selandian (Ørvig 1986). ...
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The first fossil otolith association from the middle Paleocene (Selandian) of Scania, southern Sweden is described. Forty-seven otoliths were retrieved from shallow wells representing 14 teleost taxa. Many specimens are small and/or eroded and, therefore, not identifiable to species level. Nevertheless, our findings indicate the potential for further fossil otolith discoveries in the region. The Scanian otolith-based fauna greatly resembles the better-known coeval association from Copenhagen, Denmark, but is relatively rich and diverse in perciform otoliths. The fauna records the first occurrence of Serranus? caribbaeus from the European Paleocene, and of Archaemacruroides ornatus from the Selandian of the North Sea Basin.
... Other specimens in the sample compare well with some teeth that Agassiz (1833-1843) identified as Corax kaupii (= Squalicorax kaupi), but a very similar morphology was later named Corax lindstromi (= Squalicorax lindstromi) by Davis (1890). The latter species name was only recently resurrected, and it remains to be confirmed that it truly represents a species distinct from S. kaupi, and that at least some North American teeth identified as S. kaupi should be called S. lindstromi (see Einarsson et al., 2010). The ability to draw the line between true biological species based on isolated teeth is difficult, as without the aid of numerous associated dentitions it is difficult to simply determine if differences in tooth morphology are related to intraspecific variation and/or heterodonty. ...
... Much less is known about limb-loss survival in the marine habitat. Bite marks can often be found on the limb bones of marine and terrestrial reptiles, but it is often difficult to tell whether the bite marks are pre-or post-mortem unless there is evidence of bone regrowth where the damage has occurred, showing the injury has had time to at least partially heal (Einarsson et al., 2010;Hone and Watabe, 2010;Karl, 2012;DePalma et al., 2013;Araújo et al., 2015a). ...
... During the Late Cretaceous, these regions were linked (either directly or indirectly) via shallow epicontinental seaways ( Ziegler, 1990;Voigt et al., 2008; Biernacka and J ozefiak, 2009), which would explain the perceived commonality of major faunal elements. For example, the identification of polycotylid dental remains from Opole is consistent with the SCB, as well as Cenomanian faunas from England ( Madzia, 2016;Sachs et al., 2017b), and various CenomanianeCampanian localities in European Russia and Sweden (e.g., Persson, 1959;Storrs et al., 2000;Einarsson et al., 2010). Interestingly, the Opole polycotylid teeth differ morphologically from those recovered in the adjacent BCB (see Kear et al., 2014, fig. 3) and Turonian units in western Germany (see Sachs, 2000; Sachs et al., 2017b, c), which tend to be more massive and conical, perhaps indicating taxonomic distinctions as has been reconstructed amongst polycotylids from the approximately coeval North American Western Interior Seaway (e.g., Carpenter, 1996). ...
Article
A few isolated plesiosaurian and mosasauroid squamate teeth were collected from the Opole area in southwest Poland during the late nineteenth century. Calcareous nannofossil analysis of their associated rock matrix indicates an early Turonian age (nannofossil zone UC7; Mytiloides ex gr. labiatus and Inoceramus apicalis inoceramid zones), which is significant because this constitutes a globally enigmatic interval of marine amniote evolution. The Opole plesiosaurian teeth are attributable to polycotylids, but an indeterminate mesopodial was also recovered. They are similar to specimens from the Cenomanian–Turonian in the Saxonian Cretaceous Basin of Germany and the Chalk succession of England, but differ from polycotylid remains found in the coeval Bohemian Cretaceous Basin of the Czech Republic, which are far more robust. The mosasaurid tooth crown from Opole compares favourably with dentary and maxillary teeth of a number of Turonian yaguarasaurines and basal russellosaurines, but in having well-developed carinae and a smooth labial and strongly folded/markedly striated lingual tooth surfaces it can be differentiated from taxa such as Yaguarasaurus columbianus (Colombia), Romeosaurus fumanensis and R. sorbinii (both Italy) and ‘Mosasaurus’ gracilis (England). However, a single record from the Bohemian Cretaceous Basin may refer to a conspecific form. All this suggests a potential for slight compositional differences between Cenomanian–Turonian marine amniote assemblages across central and northern Europe, although otherwise these regions probably constituted a common faunal belt bordering the Tethys Ocean.
... Persson 1959;Lindgren & Siverson 2002Lindgren 2004), elasmosaurid and polycotylid plesiosaurians (e.g. Persson 1959Persson , 1962Persson , 1963Persson , 1967Persson , 1990Einarsson et al. 2010;Sachs et al. 2015), the dyrosaurid crocodylian Aigialosuchus villandensis (Persson 1959), and aquatic hesperornithiform birds . Terrestrial non-avian dinosaurians, represented by neoceratopsians, ornithopods and a possible theropod (Lindgren et al. 2007;Poropat et al. 2015), inhabited island archipelagos (Surlyk & Christensen 1974), along with a mixed flora lowland of angiosperms (Debeya) and conifers indicated by leaves and pollen from coeval sediments in the Vomb Trough (Halamski et al. 2016). ...
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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) Lagerstätten of 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 benthic macroinvertebrates, together with pelagic cephalopods, chondrichthyans, actinopterygians and aquatic amniotes (ichthyopterygians, sauropterygians and mosasauroids). Terrestrial plant remains (lycophytes, sphenophytes, ferns, pteridosperms, cycadophytes, bennettitaleans and ginkgoes), including exceptionally well-preserved carbonized flowers, are also world famous, and are occasionally associated with faunal traces such as temnospondyl amphibian bones and dinosaurian footprints. While this collective documented record is substantial, much still awaits discovery. Thus, Scandinavia and its Arctic territories represent some of the most exciting prospects for future insights into the spectacular history of Mesozoic life and environments.
... Å sen, a well-known fossil site within the Kristianstad Basin, hosts charcoalified flowers within Santonian-lower Campanian fluvial deposits (Skarby 1968;Friis 1984;Friis et al. 2011). Within the Kristianstad Basin, the fluvial successions are overlain by marine glauconitic calcareous sandstones hosting a rich fossil biota, including a range of invertebrates (Einarsson et al. 2016), but also vertebrates including sharks and fish Siversson et al. 2015), mosasaurs, plesiosaurs (Einarsson et al. 2010) and even non-avian dinosaurians (Poropat et al. 2015). Oysters were described from Å sen showing heteromorphic ornamentation interpreted as attachment in vivo to arborescent plants (presumably mangroves: Friis & Skarby (1981)). ...
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A Late Cretaceous (Campanian) leaf megaflora from the Vomb Trough in southern Skåne, Sweden, has been investigated on the basis of collections held at the Swedish Museum of Natural History. The main plant-bearing locality is Köpinge, but single specimens originate from Högestad, Ingelstorp, Rödmölla, Svenstorps mölla and Tosterup. The fossil flora is dominated by the angiosperm (eudicot) Debeya ( Dewalquea ) haldemiana (Debey ex de Saporta & Marion) Halamski. Other dicots are cf. Dryophyllum sp., Ettingshausenia sp., Rarytkinia ? sp., Dicotylophyllum friesii (Nilsson) comb. nov. and Salicites wahlbergii (Nilsson) Hisinger. Conifers are represented by cf. Aachenia sp. (cone scales), Pagiophyllum sp. and Cyparissidium sp. (leaves). Single poorly preserved specimens of ferns and monocots have also been identified. The terrestrial palynomorphs (the focus herein) clearly link to the megaflora, although with different relative abundances. The fern spore Cyathidites dominates along with the conifer pollen Perinopollenites elatoides and Classopollis . Angiosperm pollen comprise up to 15% of the assemblage, represented by monocolpate, tricolpate and periporate pollen and the extinct Normapolles group. The spores in the kerogen residue show a thermal alteration index (TAI) of 2+. The flora probably represents mainly a coastal lowland Debeya /conifer forest, and is similar to approximately coeval assemblages from analogous palaeo-communities described from eastern Poland, western Ukraine and Westphalia.
... Scandinavian plesiosaurian fossils have been well documented from the Late Cretaceous (latest early Campanian) of Sweden (e.g. Persson 1959Persson , 1996Einarsson et al. 2010;Sørensen et al. 2013;Sachs et al. 2015), and especially the Late Jurassic (Tithonian) of Spitsbergen in the Norwegian Svalbard archipelago (e.g. Druckenmiller et al. 2012;Knutsen et al. 2012a, b, c, d;Kear & Maxwell 2013;Delsett et al. 2015). ...
Article
Early Jurassic plesiosaurian fossils are rare in the Scandinavian region, with a few isolated bones and teeth known from Bornholm, and anecdotal finds from East Greenland. The only other identifiable specimens derive from Toarcian-aged (based on ammonites) erratics deposited during Late Pleistocene glacial advances near the town of Ahrensburg, NE of Hamburg in northern Germany. The geographical source of these transported clasts is debated, but reconstructed ice-flow directions and lithofacies comparisons implicate either the offshore Baltic Sea between the Island of Bornholm and Mecklenburg–Vorpommern (Germany) or, less probably, south of the Danish Archipelago (Mecklenburg Bay). These regions collectively bordered the Fennoscandian landmass and adjacent Ringkøbing-Fyn Island in the late Early Jurassic, and were dominated by near-shore marine deltaic to basinal settings. The Ahrensburg plesiosaurian remains include postcranial elements reminiscent of both the microcleidid Seeleyosaurus and the rhomaelosaurid Meyerasaurus. These occur alongside other classic ‘Germanic province’ marine amniotes, such as the teleosaurid crocodyliform Steneosaurus and ichthyosaurian Stenopterygius cf. quadriscissus: thus, advocating faunal continuity between Scandinavia and southern Germany during the Toarcian, and a less pronounced marine reptile faunal provinciality than previously assumed.
... In these respects the two teeth are similar to those identified as S. kaupi from Campanian strata of the US Western Interior and Gulf and Atlantic Coastal plains (i.e., Cappetta & Case, 1975a;Case, 1987a;Lauginiger & Hartstein, 1983;Manning & Dockery, 1992). Bourdon et al. (2011) identified similar teeth from the Santonian of New Mexico as S. lindstromi and suggested that this species name (following Einarsson et al., 2010) be applied to North American Santonian to Maastrictian teeth previously identified as S. kaupi. A detailed comparison of the North American material to S. lindstromi remains to be undertaken, and Davis (1890) himself did not provide a direct comparison to S. kaupi, stating only that "Whilst recognizing the possibility that many of the specimens now supposed to represent separate species may ultimately be proved to have been associated in the same jaws, it may be advantageous to consider them as distinct until material shall be acquired which will render their determination certain." ...
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A diverse vertebrate assemblage was recovered from the Eutaw Formation along a stretch of Luxapalila Creek in Lowndes County, Mississippi. The assemblage is dominated by elasmobranchs but also includes osteichthyans (seven species), archosaurs (one crocodilian, two dinosaurs), and turtles (trionychid and chelonioid). Twenty one elasmobranch taxa were identified (14 selachians and seven batoids), including new species Meristodonoides multiplicatus, Lonchidion cristatum, and Cantioscyllium grandis. Our sample also enabled us to expand the known range of variation for some other poorly diagnosed species. The elasmobranch assemblage consists predominantly of species with presumed benthic habits (14), including the orectolobiform sharks and sclerorhynchid rays, whereas the seven lamniform sharks represent pelagic species. We believe that the sharks and rays inhabited a warm-water, nearshore marine environment.
... Nilsson 1836), and since then reports describing isolated dental and/or skeletal elements have been published sporadically (e.g. Lundgren 1888;Wiman 1916;Persson 1954Persson , 1959Persson , 1962Persson , 1963Persson , 1967Persson , 1990Troedsson 1954;Einarsson et al. 2010). In a recent review devoted to the Cretaceous vertebrate fauna of the Kristianstad Basin, southernmost Sweden ( Fig. 1), Sørensen et al. (2013) listed six nominal plesiosaurian taxa (Elasmosaurus? ...
Article
A partial exoccipital–opisthotic from the uppermost lower Campanian (Upper Cretaceous) of the Åsen locality, Kristianstad Basin, southernmost Sweden, is described and illustrated. The fossil represents the first braincase element of a plesiosaur found in Sweden. It includes the chamber for the ampulla and utriculus, openings for the caudal vertical and horizontal semicircular canals, and four foramina for cranial nerves. The incomplete braincase can be referred to an elasmosaurid plesiosaur, and closely resembles the exoccipital–opisthotic of Libonectes morgani and a referred specimen of Aristonectes parvidens. Although we discuss putative postcranial material of the elasmosaurid subfamily Aristonectinae in the uppermost lower Campanian of southernmost Sweden, the exoccipital–opisthotic from Åsen most likely belongs to a juvenile individual of a non-aristonectine elasmosaur.
... Discussion: Einarsson et al. (2010) reintroduced a long-overlooked taxon, Squalicorax lindstromi, for a tooth-design commonly attributed to Squalicorax kaupi, which is here regarded as one species within a suite of similar taxa that have typically been lumped under a single name. The Hosta Tongue determination is partially based upon a comparison with a larger study-set of this tooth-design from Mississippi (Santonian, Mississippi Museum of Natural Science, JB unpublished). ...
... Other specimens in the sample compare well with some teeth that Agassiz (1833-1843) identified as Corax kaupii (= Squalicorax kaupi), but a very similar morphology was later named Corax lindstromi (= Squalicorax lindstromi) by Davis (1890). The latter species name was only recently resurrected, and it remains to be confirmed that it truly represents a species distinct from S. kaupi, and that at least some North American teeth identified as S. kaupi should be called S. lindstromi (see Einarsson et al., 2010). The ability to draw the line between true biological species based on isolated teeth is difficult, as without the aid of numerous associated dentitions it is difficult to simply determine if differences in tooth morphology are related to intraspecific variation and/or heterodonty. ...
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AGr-43 is a fossil site located within a stream in central Greene County, Alabama that is bounded by the Black Warrior River to the east and the Tombigbee River to the west. The stream bed consists of fossil-rich gravel that contains large quantities of Cretaceous elasmobranch and bony fish remains, reptile and invertebrate remains, as well as carbonate and siliciclastic lithic fragments. Much of this material likely originates from the Tombigbee Sand Member of the Eutaw Formation (late Santonian to early Campanian), but some could be derived from the overlying Mooreville Chalk (late Santonian to early Campanian). Stream gravels were collected in bulk and later screened, picked, and sorted in the lab. Thus far, 28 Cretaceous fish taxa have been identified from these gravels, 22 of which are elasmobranchs and the remaining six are osteichthyans. Eleven of the specimens we discuss represent new published records for Alabama. These taxa include: Archaeolamna kopingensis, Anomoeodus barberi, Borodinopristis cf. ackermani., Carcharias sp., Ischyrhiza aff. avonicola, Lonchidion sp., Meristodonoides sp., Micropycnodon sp.?, “Pseudohypolophus” ellipsis, Squalicorax aff. yangaensis, and Texatrygon sp. Furthermore, the identification of Chiloscyllium sp. and Ischyrhiza aff. mira represent the first of these taxa reported from the Tombigbee Sand of Alabama. The identification of these 28 taxa from site AGr-43 aids in our understanding of Late Cretaceous paleobiodiversity, biostratigraphy, and paleobiogeography within the Mississippi Embayment and Western Interior Seaway.
... Within a few years, usage of the original spelling was embraced by a growing number of workers (e.g., Cook et al. 2008;Everhart 2005;Kriwet and Benton 2004;Kriwet et al. 2008;Shimada 2007;Shimada et al. 2006). Over the last few years a majority of researchers discussing or mentioning the genus in publications have used the original spelling Cretalamna (e.g., Adolfssen and Ward 2015;Andreev and Motchurova-Dekova 2010;Becker et al. 2010;Bogan and Gallina 2011;Bourdon and Everhart 2011;Cook et al. 2011Cook et al. , 2013Cumbaa et al. 2010;Cuny et al. 2012;Einarsson et al. 2010;Eriksson et al. 2011;Hamm and Cicimurri 2011;Retzler et al. 2013;Sato et al. 2012;Shimada et al. 2010;Siverson et al. 2013;Underwood and Cumbaa 2010;Underwood et al. 2011;Ward 2009). The replacement of Cretolamna with Cretalamna was strongly opposed by Cappetta (2000Cappetta ( , 2012. ...
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The type species of the extinct lamniform genus Cretalamna, C. appendiculata, has been assigned a 50 Ma range (Albian—Ypresian) by a majority of previous authors. Analysis of a partly articulated dentition of a Cretalamna from the Smoky Hill Chalk, Kansas, USA (LACM 128126) and isolated teeth of the genus from Cenomanian to Campanian strata of Western Australia, France, Sweden, and the Western Interior of North America, indicates that the name of the type species, as applied to fossil material over the last 50 years, represents a large species complex. The middle Cenomanian part of the Gearle Siltstone, Western Australia, yielded C. catoxodon sp. nov. and “Cretalamna” gunsoni. The latter, reassigned to the new genus Kenolamna, shares several dental features with the Paleocene Palaeocarcharodon. Early Turonian strata in France produced the type species C. appendiculata, C. deschutteri sp. nov., and C. gertericorum sp. nov. Cretalamna teeth from the late Coniacian part of the Smoky Hill Chalk in Kansas are ...
... Beaven and Russell (1999) reported C. steineri from the Lethbridge Coal Zone, Dinosaur Park Formation (Campanian, 75 Ma). Einarsson et al. (2010) discussed the occurrence of feeding traces on the bones of marine reptiles and mentioned the presence of scratches on bones consistent with that expected for Carcharias latus (Davis, 1890). ...
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A new, exquisitely preserved specimen of a small mosasaur, referable to Mosasaurus missouriensis, is reported from the Bearpaw Formation (ca. 75 Ma, upper Campanian) of southern Alberta, Canada. Many calcified cartilaginous elements, including tracheal rings and the sternum, are preserved. The sternum most closely resembles that of Clidastes propython, bearing five shallow sternal rib facets on each side. Our comparative study of the new material with the holotype, referred material, and the genotype M. hoffmannii is congruent with the preexisting hypothesis that M. missouriensis and M. hoffmannii are phylogenetically more closely related to each other than to the other congeners, in spite of a temporal gap of nearly 10 million years between them. Also preserved with the mosasaur, inside its ribcage and around the specimen, are well-preserved aulopiform fish bones, including a skull. The fish skull is punctured and its centra truncated, suggesting macrophagy was employed by M. missouriensis despite the apparent lack of tooth wear. A sympatric specimen of Prognathodon overtoni is known to have consumed a sea turtle as well as fishes, and consistently exhibits apical wear across marginal teeth. We hypothesize that coexistence of these apex predators in the Bearpaw Sea was possible because of niche partitioning. Finally, the mosasaur carcass was likely scavenged by at least three lamniform sharks, based on their shed teeth and a series of truncated transverse processes on the mosasaur tail.
... Vertebrates are mainly preserved as isolated bones and teeth in this locality, representing sharks and rays, marine teleost fishes, marine turtles, plesiosaurs, mosasaurs, crocodylians, a herbivorous dinosaur, and enantiornithine birds (Persson, 1959(Persson, , 1963Siverson, 1992Siverson, , 1993Rees, 1999;Siverson, 2002, 2004;Lindgren, 2004Lindgren, , 2005Rees and Lindgren, 2005;Lindgren et al., 2007;Einarsson et al., 2010). Horizon-Latest early Campanian, Belemnellocamax mammillatus zone. ...
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Fossil soft-shelled turtles (Trionychidae) have so far been recognized in all continents except Antarctica, based largely on remains preserving their diagnostic sculptured shell bones. The origin of the group is generally assumed to be in the Early Cretaceous of Asia, whereas they first appear in North America and Europe during the Late Cretaceous and Paleocene, respectively. Here we describe the first record of an indeterminate trionychid from the late early Campanian from southern Sweden, a part of the paleobiogeographically isolated Fenno-Scandian Shield, thus extending the stratigraphic record of the group in Europe back about 15 Ma into the Late Cretaceous. Our finding provides evidence against the currently favored dispersal scenario in which trionychid turtles are interpreted to have come to Europe first during the Paleocene either directly from North America or via Asia. The described indeterminate trionychid possibly represents a relic of a pre-Cretaceous endemic radiation of North European trionychids living mainly on the Fenno-Skandian Shield or it may indicate a potential lower latitude dispersal route of trionychids from Asia to North America via Europe during the Late Cretaceous.
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Observations of temporal overlap of niche occupation among Late Cretaceous marine amniotes suggest that the rise and diversification of mosasauroid squamates might have been influenced by competition with or disappearance of some plesiosaur taxa. We discuss that hypothesis through comparisons of the rates of morphological evolution of mosasauroids throughout their evolutionary history with those inferred for contemporary plesiosaur clades. We used expanded versions of two species-level phylogenetic datasets of both these groups, updated them with stratigraphic information, and analyzed using the Bayesian inference to estimate the rates of divergence for each clade. The oscillations in evolutionary rates of the mosasauroid and plesiosaur lineages that overlapped in time and space were then used as a baseline for discussion and comparisons of traits that can affect the shape of the niche structures of aquatic amniotes, such as tooth morphologies, body size, swimming abilities, metabolism, and reproduction. Only two groups of plesiosaurs are considered to be possible niche competitors of mosasauroids: the brachauchenine pliosaurids and the polycotylid leptocleidians. However, direct evidence for interactions between mosasauroids and plesiosaurs is scarce and limited only to large mosasauroids as the predators/scavengers and polycotylids as their prey. The first mosasauroids differed from contemporary plesiosaurs in certain aspects of all discussed traits and no evidence suggests that early representatives of Mosasauroidea diversified after competitions with plesiosaurs. Nevertheless, some mosasauroids, such as tylosaurines, might have seized the opportunity and occupied the niche previously inhabited by brachauchenines, around or immediately after they became extinct, and by polycotylids that decreased their phylogenetic diversity and disparity around the time the large-sized tylosaurines started to flourish. Subjects Ecology, Evolutionary Studies, Paleontology
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Here we describe multiple pathological skeletal elements in a specimen assigned to a globidensine mosasaur as Prognathodon cf. sectorius. This individual, NHMM 2012 072, was recovered from the upper Lixhe 3 Member (Gulpen Formation, upper Maastrichtian) near Maastricht, the Netherlands. In all likelihood, it was bitten in the snout by a large, possibly conspecific mosasaur – and survived this attack. The specimen described here is among the very few with clear and unambiguous evidence of (very likely intraspecific) agonistic interactions amongst mosasaurs. Despite significant injuries, including partial amputation of the premaxilla, this animal initially recuperated from the encounter, but the subsequent infectious processes as a result of this attack was still ongoing at the time of death. Radiological and morphological features suggest chronic osteomyelitis which led to loss of bone within the left maxilla, which probably hampered the ability to feed, potentially contributing to its demise. This case study illustrates the potential of integrative three-dimensional approaches in palaeopathological studies to provide a much more comprehensive and detailed description of alterations and underlying physiological processes.
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Direct evidence of paleoecological processes is often rare when the fossil record is poor, as in the case of the Cretaceous of eastern North America. Here, I describe a femur and partial tibia shaft assignable to theropods from two Late Cretaceous sites in New Jersey. The former, identifiable as the femur of a large ornithomimosaur, bears several scores interpreted as shark feeding traces. The tibia shaft has punctures and flaked bone from the bites of mid-sized crocodyliforms, the first documented occurrence of crocodyliform traces on dinosaur bone from the Maastrichtian of the Atlantic Coastal Plain. The surface of the partial tibia is also littered with indentations interpreted as the traces of invertebrates, revealing a microcosm of biological interaction on the coastal seafloor of the Cretaceous Atlantic Ocean. Massive crocodyliforms, such as Deinosuchus rugosus and the slightly smaller Deltasuchus motherali , maintained the role of terrestrial vertebrate taphonomic process drivers in eastern North America during the Cretaceous. The report of crocodyliform bite marks on the ornithomimosaur tibia shaft in this manuscript reinforces the importance of the role of crocodyliforms in the modification of terrestrial vertebrate remains during the Cretaceous in North America. The preserved invertebrate traces add to the sparse record of the presence of barnacles and other marine invertebrates on dinosaur bone, and the evidence of shark feeding on the ornithomimosaur femur support the “bloat-and-float” model of terrestrial vertebrate fossil deposition in marine deposits from the Cretaceous of eastern North America.
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Direct documentation of the ecology of past life is often rare when the fossil record is comparatively poor, as in the case of the terrestrial fauna of the Maastrichtian of eastern North America. Here, I describe a femur and partial tibia shaft assignable to theropods from the Maastrichtian Big Brook locality of New Jersey. The former, identifiable to a previously undetected morphotype of large ornithomimosaur, bears several scrapes identifiable as the feeding traces of sharks, adding to the collection of terrestrial vertebrate remains bearing such marks from the state. The latter is littered with tooth marks and punctures from possibly multiple crocodyliform individuals, the first documented occurrence of such traces on dinosaur bone from the Maastrichtian of the Atlantic Coastal Plain. Additionally, its surface is dotted with likely traces of invertebrates, revealing a microcosm of biological interaction from the Maastrichtian New Jersey shoreline. Previously, the massive Campanian crocodylian taxon Deinosuchus rugosus and the slightly smaller Cenomanian-age Texas crocodyliform Deltasuchus motherali have been shown as important drivers of terrestrial vertebrate taphonomy in eastern North America. The report of crocodyliform bite marks on the ornithomimosaur metatarsal shaft in this manuscript reveals that crocodylians continued to play role in the taphonomy of large dinosaurs in eastern North America through the end of the Mesozoic. The preserved invertebrate traces add to the sparse record of their traces on dinosaur bone, and the presence of shark scrapes on the femur supports the “bloat-and-float” model of terrestrial vertebrate fossil deposition in eastern North America.
Article
Kear, B.P., Fordyce, R.E., Hiller, N. & Siversson, M., December 2017. A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods. Alcheringa 00, 000-000. ISSN 0311-5518. THE LAST 15 years has witnessed a blossoming of research on Australasian Mesozoic marine tetrapod fossils. Much of this work has focused on amniotes, particularly those from the prolific Lower Cretaceous (Aptian–Albian) Lagerstätten of the Eromanga Basin in central and eastern Australia, and Upper Cretaceous (Campanian–Maastrichtian) sequences of the North and South islands of New Zealand. However, rare and less popularized remains have also been found in Lower Triassic–mid-Cretaceous rocks from Australia, New Zealand and the Chatham Islands, and on the tectonically proximal landmasses of New Caledonia and Timor. Currently identified taxa include estuarine–paralic rhytidostean, brachyopid, capitosaurian and trematosaurian temnospondyls from the earliest Triassic (Induan–Olenekian), Middle–Late Triassic (Anisian–Norian) eosauropterygians, and mixosaurian, shastasaurian and euichthyosaurian ichthyosaurians, Early–Middle Jurassic (Sinemurian–Bajocian) ichthyosaurians, together with plesiosauroid and rhomaleosaurid-like plesiosaurians, and diverse Early (Aptian–Albian) through to Late Cretaceous (Campanian–Maastrichtian) elasmosaurid, leptocleidid, polycotylid, probable cryptoclidid and pliosaurid plesiosaurians, as well as ophthalmosaurid ichthyosaurians, sea turtles incorporating protostegids, and mosasaurid squamates. This faunal succession evidences almost continuous occupation of southern high-palaeolatitude seas, and repeated endemic diversifications (including nascent members of some key lineages) amongst emigrant cosmopolitan clades. The primary dispersal routes are likely to have been peri-Gondwanan, with coastal migrations along the western Tethys and polar margins of the Panthalassan Ocean. However, augmentation by increasing continental fragmentation and seaway corridor connectivity probably occurred from the Middle Jurassic to Late Cretaceous. Latest Cretaceous mosasaurid and elasmosaurid taxa also reveal regional affinities with the emergent western Pacific and Weddellian austral bioprovinces. The extreme rarity, or complete absence, of many major groups prevalent elsewhere in Gondwana (e.g., tanystropheids, Triassic sauropterygians, bothremydid marine turtles, thalattosuchians and dyrosaurid crocodylomorphs) is conspicuous, and might be related to stratigraphical/collecting biases, or the predominantly higher-palaeolatitude, cooler-water Mesozoic palaeogeography of the Australasian region. Although the burgeoning record is substantial, much still awaits discovery and adequate documentation; thus Australasia is still one of the most exciting prospects for future insights into the global history of Mesozoic marine tetrapods. Benjamin P. Kear* [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyvägen 16, SE-752 36 Uppsala, Sweden; R. Ewan Fordyce [ewan.fordyce@otago.ac.nz] Department of Geology, University of Otago, Post Box 56, Dunedin 9054, New Zealand; Norton Hiller [norton.hiller@gmail.com] Canterbury Museum, Rolleston Avenue, Christchurch 8013, New Zealand; Mikael Siversson [mikael.siversson@museum.wa.gov.au] Western Australian Museum, 49 Kew Street, Welshpool, Western Australia 6106.
Article
A thin phosphate-granule conglomerate within the Upper Cretaceous (middle Campanian) Rattlesnake Mountain sandstone member of the Aguja Formation preserves a diverse chondrichthyan and osteichthyan fauna. This highly fossiliferous deposit (the ‘Ten Bits Microsite’) yielded about 5000 teeth, spines, and denticles in a small amount of matrix (c. 150 kg). About 30 identifiable species of sharks, rays, and bony fishes are recognized. Two of the three most abundant chondrichthyan species at Ten Bits (Scapanorhynchus texanus and Ischyrhiza mira) are also the most common species in other middle to late Campanian marine vertebrate faunas along the Gulf and Atlantic Coastal Plain. The myliobatiform rays Brachyrhizodus and Rhombodus that occur at Ten Bits also appear to be characteristic of the Gulf and Atlantic Coast, as are lamniform sharks such as Cretalamna and Serratolamna. These taxa are entirely absent or extremely rare in Western Interior Campanian faunas. In contrast, some small orectolobiform sharks (Cantioscyllium, Chiloscyllium, Columbusia) and small rays (Protoplatyrhina) found at Ten Bits are common in shallow water faunas of the Western Interior and Texas Coastal Plain, but rarely reported from the eastern Gulf or Atlantic Coast. The common Western Interior ray Myledaphus bipartitus does not occur at Ten Bits or in any Gulf or Atlantic Coast fauna. Ptychotrygon agujaensis is abundantly represented in the Ten Bits fauna, but unknown in correlative marine faunas. Although Ptychotrygon occurs in all Western Interior, Gulf and Atlantic Coastal Plain faunas, it is represented elsewhere by apparently endemic species at each collection site. The differences between Western Interior, Gulf, and Atlantic Coastal Plain faunas probably reflect latitudinal variation in water temperature or salinity, or different oceanic water circulation patterns between the Western Interior Seaway and the Gulf or Atlantic Coast that restricted the distributions of some marine fish species. The Ten Bits fauna shares typical species with both Western Interior and Gulf and Atlantic Coast faunas, reflecting its position at the border between these provinces; however, the dominant taxa found at Ten Bits are the same as those found on the Gulf and Atlantic Coast, and indicate that western Texas was more closely allied biogeographically with that province than with the Western Interior of North America. One species tentatively identified in the Ten Bits fauna on the basis of a single tooth, Igdabatis cf. I. indicus, is otherwise known only from southern Europe and Asia, although a similar large myliobatid ray also occurs rarely in Texas Coastal Plain faunas. These occurrences indicate that western Texas may have been near the northern limit of the range for some tropical Tethyan marine vertebrate species.
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Evidence from the Pierre Shale (Late Cretaceous) of South Dakota is presented for an attack on a juvenile Hesperornis by a polycotylid plesiosaur. The wound healed and the Hesperornis grew to maturity. Evidence of survival provides our best information about predator prey interactions in the fossil record but are rare for birds where survival is an unlikely outcome.
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Wretman, L. & Kear, B.P., 2013. Bite marks on an ichthyodectiform fish from Australia: possible evidence of trophic interaction in an Early Cretaceous marine ecosystem. Alcheringa 38, 000–000. ISSN 0311-5518.A well-preserved fish skull from late Albian deposits of the Allaru Mudstone near Richmond in Queensland displays a conspicuous V-shaped pattern of indentations, punctures and depression fractures consistent with a vertebrate bite trace. This is the first direct evidence of trophic interaction between vertebrates within an Early Cretaceous marine ecosystem from Australia. The specimen is taxonomically referable to the large-bodied (ca 1 m snout–tail length) ichthyodectiform Cooyoo australis, but the size and spacing of the tooth marks is incompatible with attack by a conspecific individual. The lack of osseous growths concordant with healing also suggests that the bite occurred shortly before or after the animal’s death. Comparison with the dentitions of other coeval vertebrates indicates compatible tooth arrangements in longirostrine amniote predators such as polycotylid plesiosaurians, ornithocheiroid pterosaurs and especially the ichthyosaurian Platypterygius. The implications of this as a potential predator–prey association are that Early Cretaceous actinopterygians occupied middle-level trophic niches and were in turn consumed by higher-level amniote carnivores, similar to many extant marine vertebrate communities of today.Lovisa Wretman [lovisa.wretman@ebc.uu.se], Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden (address for correspondence); Benjamin P. Kear [benjamin.kear@geo.uu.se], Palaeobiology Programme, Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala, Sweden. Received 8.8.2013, revised 17.9.2013, accepted 23.9.2013.
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The predominance of juveniles from one taxon is rarely found in faunal studies. However, the presence of seven juveniles in a sample of ten cryptocleidoid plesiosaurs from the Redwater Shale Member of the Sundance Formation of Natrona County, Wyoming may be such a paleocommunity. Juvenile characters are recognized by the lack of facets and ossification on the distal ends of the propodials and by cross-sections of the limbs. Juveniles have dense pachyosteosclerotic bone structures whereas adults have more spongy, osteoprotic bone. The dense bone of the juveniles suggests a difference in environmental preference between juvenile and adult plesiosaurs.
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The left front paddle of an unidentified elasmosaurid in the collection of the Fick Fossil and History Museum exhibits two groups of deeply incised grooves across the dorsal and ventral sides of the humerus that suggest a series of bites by the lamniform shark, Cretoxyrhina mantelli. The remains were discovered by George F. Sternberg in 1925 in the Smoky Hill Chalk Member of the Niobrara Chalk, Logan County, Kansas, USA. Archival photographs, along with Sternberg's hand written note, document the condition of the specimen when originally collected. The specimen is significant because it preserves the first evidence of probable feeding by C. mantelli on an elasmosaurid, and because it represents the rare occurrence of an elasmosaurid in the upper Smoky Hill Chalk of western Kansas. Contents
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The Plesiosauria, large Mesozoic marine reptiles, have been regarded as dominant predators in Mesozoic seas, although there is only a little (including some doubtful) direct evidence of their stomach contents1, 2, 3,. Here we report the occurrence in Hokkaido, northern Japan, of a partial skeleton of a Cretaceous short-necked plesiosaur together with a large number of isolated ammonoid jaws. This is, to our knowledge, the first description of the stomach contents of a polycotylid plesiosaur, and the first firm evidence of prey-predator relationships between plesiosaurs and ammonites.
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Aside from large sharks such as Cretoxyrhina mantelli, there are no other marine species known from the Late Cretaceous which could challenge the role of mosasaurs as apex predators. From the evidence of the injuries observed on mosasaur remains, however, it is likely that they occasionally fought with or were attacked by other mosasaurs. Sometimes the injuries incurred in this combat were non-fatal and show evidence of healing prior to the death of the mosasaur, while in other instances, the injuries were apparently fatal. The well-preserved skull and lower jaws of the holotype specimen of Tylosaurus kansasensis (FHSM VP-2295) in the collection of the Stemberg Museum of Natural History exhibit readily visible punctures and gouges on the frontal, left prefrontal, right dentary and right articular that are attributable to the bite of a larger mosasaur. These deep and unhealed bite marks on the skull, as well as a possible broken neck, suggest that this individual died from injuries received when its skull was bitten and possibly crushed by another mosasaur.
Article
The Maastrichtian of southern Sweden has yielded more than 2000 teeth of squaloid sharks. Seven species have been identified: Microetmopterus wardi gen. et sp. nov., Poretmopterus hemmooriensis gen. nov., Eoetmopterus cf. E. supracretaceus, Centroscymnus schmidi, Squalus ballingsloevensis sp. nov., S. balsvikensis sp. nov. and S. gabrielsoni sp. nov. Etmopterine sharks, now restricted to the cold bottom-waters of the outer continental and insular shelves and slopes, apparently thrived in the shallow coastal waters of the Kristianstad Basin During the earliest Maastrichtian. As indicated by its extremely small teeth, Microetmopterus wardi may have been the smallest known neoselachian. -from Author
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When extracting or cleaning phosphatic fossils using acetic acid, the solutions must be buffered with calcium acetate to a pH greater than 3.6 for conodont and many fish taxa, and to a slightly greater pH for some conulariid, shark, and some fish taxa. Diagrams of the changes in pH and density during dissolution, rate of dissolution, and productivity per liter of acid provide a means for selecting the economically optimal process, monitoring the progress, and adjusting the composition of the solution when necessary.
Remains of three species of hybodont sharks have been found in the Late Cretaceous strata of the Kristianstad Basin. Two species of Polyacrodus, P. sp. and P. siversoni n. sp., are recorded from Ullstorp and Äsen respectively. The two species are probably part of the same lineage and P. siversoni represents one of the youngest records of Polyacrodus so far. The third species is Hybodus sp., closely related to H. montanensis, from the Campanian of Montana and Wyoming, USA.
Chapter
One of the rarest of marine reptiles is the mosasaur genus Globidens, characterized by a massive, bulbous dentition. The rarity of the taxon, coupled with the bulbous dentition, resulted in various theories concerning life habits. Although a consensus indicates that the dentition was adapted for crushing resistant elements, hypotheses have varied concerning prey, ranging from turtles or bivalves to scavenging. Finally, a partial skeleton of Globidens has been recovered from the Big Bend area of the Missouri River in central South Dakota. The specimen was discovered in the upper DeGrey Formation (upper Campanian) of the Pierre Shale Group. During analysis, bivalve fragments were found packed within the rib-cage region of the skeleton. In the field, bivalve concentrations did not occur laterally or above or below the skeleton, indicating that they were the stomach contents of the mosasaur. Associated within the stomach area are a number of bivalve taxa, including oysters and small bivalves with lamellar shells, probably of the genus Anomia. The most common specimens within the stomach area are bivalves that exhibit a prismatic shell microstructure typical of inoceramids. Four inoceramid shell morphotypes were recovered, including a coarse-ribbed morphotype, a fine-ribbed morphotype, one with a thickened umbo, and a large, flat, thin-shelled morphotype. Because of their position in the mosasaur, their fragmented condition, limited taxonomic diversity, and absence from surrounding sediments, the bivalves are considered stomach contents. Some smaller, complete shells of Anomia escaped breakage, whereas larger inoceramids were invariably crushed. Chondrichthyan teeth were found associated but are interpreted to be the result of scavenging. This specimen of Globidens appears to have had a preference for the large, flat, relatively thin-shelled inoceramids that contained a large, fleshy visceral mass.
Article
Several specimens of the Late Cretaceous lamniform shark, Cretoxyrhina mantelli (Agassiz), from the Niobrara Chalk of Kansas suggest that the shark fed on teleosts, mosasaurs, and possibly plesiosaurs. These animals are active vertebrates, so C. mantelli probably occupied the apex of the food chain in the Late Cretaceous seas. This top predator, however, was probably scavenged frequently by anacoracid sharks. Carcharodon carcharias (great white shark) and carcharhinid sharks are considered as the modem guild counterparts for Cretoxyrhina mantelli and anacoracids, respectively.
Article
A rich lamniform selachian fauna, comprising twelve species, is recorded from the informal B. mammillatus zone of the Kristianstad Basin. Five new taxa, including a North American one, are introduced. Parasymphyseal teeth of Cretolamna are described for the first time, indicating a close kinship to Cretoxyrhina. A possibly temperature-controlled relatively high degree of endemism is demonstrated for several small to medium sized Campanian odontaspidids. It is concluded that the diversity of lamniform sharks may have been linked to the great abundance of belemnites in the basin during the B. mammillatus time. Davis's 1890 paper on Scandinavian Cretaceous/Palaeocene selachians is revised concerning the lamniforms, clarifying many locality data errors. -from Author
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Shallow marine, nearshore strata of earliest Campanian (Gonioteuthis granulataquadrata belemnite Zone) and latest Early Campanian (informal Belemnellocamax mammillatus belemnite zone) age in the Kristianstad Basin, southern Sweden, have yielded isolated leptoceratopsid teeth and vertebrae, representing the first record of horned dinosaurs from Europe. The new leptoceratopsid occurrence may support a European dispersal route for the Leptoceratopsidae, or may represent an entirely endemic population. The presence of leptoceratopsid teeth in shallow marine deposits contradicts previous hypotheses suggesting that basal neoceratopsians mainly preferred arid and/or semi-arid habitats far from coastal areas.
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Histological observations of homologous bones (vertebrae, ribs, humerus, phalanges) among conspecific juvenileand adult Upper Cretaceous plesiosaurs from New Zealand (elasmosaurs and pliosaurs) demonstrates a unique “ontogenetic trajectory” of skeletal histogenesis in these animals. While juveniles demonstrate a “pachyosteosclerotic” condition of the skeleton, adults have a very light “osteoporotic-like” bone structure. Until now, one or the other of these histological specializations was known among aquatic tetrapods, adapted along contrasting pathways to this environment, either by ballasting (pachyosteosclerosis; e.g. sirenians) or by lightening (osteoporotic-like adaptation: e.g. modern cetaceans) of the skeleton. The successive occurrence of these constrasting conditions during ontogenesis of a single organism had never been reported, as far as we know, but could well be an ontogenetic characteristic of Plesiosaurs sensu lato. The significance of these findings are discussed in various phylogenetical, functional and paleoecological contexts. The ontogenetic trajectory of the plesiosaur skeleton is interpreted within the general framework of developmental heterochrony. Specifically, it suggests that juvenile plesiosaurs kept a conservative (plesiomorphic) ecology for sauropterygians, as poorly mobile, lagoon or shore dwellers while, in contrast, the adults would shift towards much more active locomotory behaviors in the open sea.
Article
Isolated marginal tooth crowns of the early Campanian mosasaur Hainosaurus Dollo, 1885, from the Kristianstad Basin and the Vomb Trough, southern Sweden, are described and illustrated. The teeth have been collected from a narrow stratigraphic interval corresponding to the highest belemnite zone in the lower part of the European two-fold division of the Campanian stage. A reexamination of dental and skeletal characters in two alleged species of Hainosaurus, ‘H.’ pembinensis Nicholls, 1988 and ‘H.’ gaudryi (Thévenin, 1896), and detailed comparisons with the corresponding elements in H. bernardi Dollo, 1885 and Tylosaurus proriger (Cope, 1869a), strongly indicate that ‘H.’ pembinensis and ‘H.’ gaudryi are both Tylosaurus Marsh, 1872. Diagnostic features of Hainosaurus include a very small infrastapedial process on the quadrate (conspicuous protuberance in Tylosaurus), flattened, symmetrically bicarinate marginal teeth (asymmetric and conical in Tylosaurus), short and wide pygal centra, and anteriorly situated intermediate caudal vertebral centra with dorsoventrally thin transverse processes (markedly triangular centra and thick processes in Tylosaurus).
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Remains of late Campanian and earliest Maastrichtian mosasaurs from southern Sweden are illustrated and briefly described. Plioplatecarpus sp. and Prognathodon sp. have been identified from strata of middle late Campanian age, while earliest Maastrichtian deposits contain remains of Mosasaurus cf. lemonnieri and Plioplatecarpus cf. primaevus. Available data suggest that the mosasaur group increased steadily in diversity from the late Coniacian until close to the early/late Campanian boundary, at which a seemingly catastrophic event severely reduced the number of species in, at least, North America and northern Europe. The extinction favoured a radiation of more derived mosasaur taxa which persisted until the end of the Maastrichtian Stage. Although the mechanism responsible for this profound mid-Campanian mosasaur faunal turnover remains unknown, it is clear that the marine reorganization affected markedly different and widely separated environments.
Article
The large reptilian marine predators of the Mesozoic preyed upon pelagic animals such as bony fish, sharks, soft cephalopods, belemnoids, ammonoids, and even each other. All had undifferentiated conical teeth of one of several forms ranging from a blunt, bulbous shape to a slender, sharply pointed cone, to a robust, slightly compressed cone with two distinct cutting edges. Tooth form, along with tooth wear and occasionally preserved stomach contents, suggests the preferred prey of each species.Seven somewhat overlapping predator types, or guilds, can be defined on the basis of tooth form and prey preference. Members of each guild have tooth morphologies which fall within a defined range, and thus they probably shared the same preferred prey. The guilds present in six well-preserved faunas of the Jurassic and Cretaceous illustrate the structure of and changes in the large marine predator adaptive zone. Six guilds co-existed for most of the Jurassic. Although the composition of some of the guilds changed in the Middle Jurassic, the kinds and number of guilds remained constant. Sometime before the Late Cretaceous, however, there was a major reorganization of the large marine predator adaptive zone resulting in a reduction in the number of reptilian guilds to three. Although the number of guilds increased in the later part of the Late Cretaceous, reptilian predators never attained their earlier diversity before the Cretaceous-Tertiary extinction ended their reign as the dominant large marine predators.
Article
In Cenomanian time, the deeply weathered Precambrian bedrock of southern Sweden was transgressed by a shallow sea, resulting in the formation of an archipelago with low islands and peninsulas during early Campanian time. On one of these islands, a high-diversity fauna characteristic of a rocky coast ecosystem is found comprising nearly all levels of the food pyramid from phytoplankton and zooplankton to reptiles. The fauna is dominated by bivalves, especially oysters, and includes the northernmost Upper Cretaceous reef corals and rudists. Three distinct epifaunal zones exist: the lowest zone is characterized by large numbers of serpulids and occupies the underside of the boulders; the next higher zone is found on the vertical sides of the boulders and is characterized by oysters and a large, vertically orientated craniacean brachiopod; and the highest zone occupies the upper part of the vertical sides and the rounded upper surfaces of the boulders and is characterized by spondylid bivalves. All species normally had a clumped distribution. The zonation is interpreted as a result of the combined effect of negative phototropism (serpulids), protection against sedimentation (craniaceans), and tolerance of strong turbulence, occasional exposure, and limited competition by other species for space (spondylids).
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The angiosperme, or flowering plants, are believed to have originated and diversified during the Cretaceous. The earliest angiosperm fossils are pollen and leaf impressions found in late early Cretaceous strata1,2. We now describe the discovery of fossil flowers in the Upper Cretaceous of Sweden which represent a significant addition to our very limited knowledge of the floral structure of Cretaceous angiosperms.
Article
At Ullstorp, close to the fault of the Nävlingeåsen horst in northeastern Scania, Sweden, a 10 m thick Upper Cretaceous terrigenous clastic section underlies medium grained bioclastic limestones. The clastic section is interpreted as having been deposited rapidly in a nearshore environment. The interpretation is based on paleontological and lithological grounds. Two conglomerate beds in the section are interpreted as a result of storm events. A third conglomerate bed, composed of matrix supported angular clasts (many of them glauconite coated), is interpreted as a debris flow deposit. Negative sedimentation is indicated by a glauconite coated hardground near the top of the sequence. Changes in sea level are reflected in the composition of the foraminiferal fauna. Other faunal elements comprise benthic invertebrates of nearshore origin, including a large inoceramid specimen.
Article
A nearly complete skeleton of an elasmosaurid plesiosaur (NJSM 15435) from the Sharon Springs Member (Middle Campanian) of the Pierre Shale, Logan County, Kansas, is associated intimately with fragmentary fish remains and numerous gastroliths. The fish bones and gastroliths were located just behind the pectoral girdle in the abdominal region. Identifiable prey includes Enchodus and other small clupeomorph fishes. An isolated tooth of the anacoracid shark Squalicorax cf. S. pristodontus also was recovered in this area. Ninety-five gastroliths (6.8 kg) were present, with the largest stone measuring 15.1 × 8.5 × 5.7 cm (5.0 × 3.3 × 2.2 in.) and weighing 1.06 kg (2.3 lb.). Many of the gastroliths are composed of pink or gray Sioux Quartzite, which suggests that the source of these stones was about 600 km (475 mi) to the northeast of where the elasmosaur remains were discovered. The association of fragmentary fish remains and gastroliths within the abdomen of NJSM 15435 supports the contention that the stones aided in the breakdown of food in plesiosaurs.
Article
The nominal species Mosasaurus ivoensis from the latest early Campanian of the Kristianstad Basin in southern Sweden, is redescribed and assigned to the tylosaurine genus Tylosaurus on the basis of its dental and vertebral morphology. A partial skeleton (KUVP 1024) from the late Coniacian to earliest Campanian Smoky Hill Chalk Member of the Niobrara Formation in western Kansas, USA, was previously referred to “ M ”. ivoensis . Nevertheless, its marginal teeth are markedly different, both in size and morphology, from those of topotypic T. ivoensis . Examination of type specimens and topotypic material of the nominal tylosaurines Hainosaurus pembinensis from the late early Campanian of Manitoba, Canada, H. gaudryi from the late Santonian or early Campanian of northwestern France, and H. lonzeensis from the Coniacian or Santonian of Belgium, indicates that all three may be Tylosaurus . The utility of isolated tooth-crowns in mosasaur taxonomy has been hampered by the often poor quality of the published illustrations of these fossils in combination with poor stratigraphic control. All Swedish remains of T. ivoensis , including 172 marginal teeth, 6 pterygoid teeth, several jawbone fragments and 12 vertebrae, were collected from a narrow stratigraphic interval corresponding to the highest biozone in the German eight-fold division of the early Campanian, providing the first good insight into the intraspecific dental variation in a tylosaurine mosasaur.
Article
A characteristic etching trace, comparable to those produced by pedicles of some Recent brachiopods, was found on a Late Cretaceous, Campanian oyster shell from a mangrove-like setting in the Åsen quarry, Sweden. The trace fossil belongs to the ichnospecies Podichnus centrifugalis Bromley & Surlyk, 1973 and is, together with a single specimen of Crania craniolaris Linnæus, 1758, the only evidence of brachiopods in the mangrove-like environment.
Article
Kaiwhekea katiki gen. et sp. nov. represents the first described cryptoclidid plesiosaurian from New Zealand. It is one of the largest cryptoclidids known, at a length of over 6.5 m, and represents the third reported genus of austral Late Cretaceous cryptoclidids. Kaiwhekea katiki is from siltstones of the Katiki Formation, upper Haumurian Stage (Cenomanian–Maastrichtian; c. 69–70 Ma) of coastal Otago, South Island, New Zealand. In the Late Cretaceous, the locality lay close to the polar circle. The holotype and only known specimen is an articulated skeleton with skull, preserved mostly as natural molds, but which lacks the forelimbs and pectoral girdle. The skull is relatively large and possesses several distinct characters, including a substantial, deep, jugal. There are about 43 upper and 42 lower teeth in each jaw quadrant; all are homodont, slim, and slightly recurved, lacking prominent ornament. Kaiwhekea probably took single soft-bodied prey. Based on cranial structure, it clearly belongs with the Cryptoclididae, but is not certainly close to the southern Late Cretaceous cryptoclidids Morturneria (Seymour Island, Antarctica) and Aristonectes (Chile, Argentina).
Article
The occurrence of marine turtles in the diet of white sharks, Carcharodon carcharias, is reviewed worldwide. Four records of chelonians eaten by white sharks in the Mediterranean Sea are described, which on the basis of carapace remnants confirmed both the loggerhead Caretta caretta and green turtle Chelonia mydas to be preyed upon in those waters. The condition of these remains indicates that large white sharks can ingest turtles essentially intact. As well as falling prey to white sharks, we suspect that some interactions involve turtles being grab-released in a non-predatory mannner and their survivability from such low-intensity bites or other mouthings may be quite high. The white shark may be the chief marine predator of adult chelonians in the Mediterranean Sea, albeit the impact of this predation upon turtle populations is nominal compared to other sources of mortality. Further, we give an account describing an adult ocean sunfish, Mola mola, in the stomach of a white shark taken in Italian waters.
Article
Owners of reptiles are beginning to demand the same level of care for their companions as do our canine and feline clients. One of the more common presenting complaints of the reptilian patient is gastrointestinal (GI) disease. Signs associated with GI disease include: anorexia, polyphagia, pica, prolapse, regurgitation, diarrhea, constipation, lethargy, and weight loss. Diagnostic modalities commonly employed in domestic species can be employed in reptiles. Anemnesis, physical examination, imaging techniques, and fecal parasite analyses are most important in herpetological medicine, as the two most common causes of GI disease are parasites and obstructive phenomena. This article reviews reported causes of GI disease and is arranged in the same manner that many would generate a list of differential diagnoses using the DAMNIT (Degenerative, Anatomic, Metabolic, Neoplastic/Nutritional, Inflammatory/Infectious, Toxic/Traumatic) scheme.
Article
A remarkable encounter between two Cretaceous mosasaurs of the same species and a sick or recently dead nautiloid (Argonautilus catarinae Sundberg) is recorded. It is possible that the mosasaur was training its young to attack shelled cephalopods. This is the first recorded attack by two mosasaurs on a nautiloid in the eastern Pacific Ocean, although ammonites preyed upon by mosasaurs are known from the west coast of North America.
Article
A partial skeleton of Daspletosaurus sp. from the Late Cretaceous (Campanian) Two Medicine Formation of western Montana preserves the first gut contents reported for a tyrannosaurid. Associated remains found with this skeleton consist of acid-etched vertebrae and a fragmentary dentary from juvenile hadrosaur dinosaurs. Hadrosaur bonebed data and comparisons of hadrosaur and tyrannosaurid limb proportions suggest that juvenile hadrosaurs represented both an abundant and accessible food source. The surface corrosion exhibited by the hadrosaur elements matches that produced by stomach acids and digestive enzymes in a wide variety of living vertebrates. Based upon these and other gut contents, and also upon tooth-marked bone studies, it appears that Daspletosaurus and most theropods ingested and digested prey in a manner similar to that of extant archosaurs (crocodilians and birds), employing a two-part stomach with an enzyme-producing proventriculus followed by a thick-walled muscular gizzard. This two-part stomach appears to be an archosaur synapomorphy.