| 1. |
- Agnolin, Federico L., et al.
(författare)
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New alvarezsaurid (Dinosauria, Theropoda) from Latest Cretaceous of North-western Patagonia with associated eggs
- 2012
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 35, s. 33-56
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Tidskriftsartikel (refereegranskat)abstract
- The Alvarezsauridae represents a branch of peculiar basal coelurosaurs with an increasing representationof their Cretaceous radiation distributed worldwide. Here we describe a new member of the group, Bonapartenykus ultimus gen. et sp. nov. from Campanian-Maastrichtian strata of Northern Patagonia, Argentina. Bonapartenykus is represented by a single, incomplete postcranial skeleton. The morphologyof the known skeletal elements suggests close affinities with the previously described taxon from Patagonia, Patagonykus, and both conform to a new clade, here termed Patagonykinae nov. Two incomplete eggs have been discovered in association with the skeletal remains of Bonapartenykus, andseveral clusters of broken eggshells of the same identity were also found in a close proximity. These belong to the new ooparataxon Arriagadoolithus patagoniensis of the new oofamily Arriagadoolithidae, which provides first insights into unique shell microstructure and fungal contamination of eggs laid by alvarezsaurid theropods. The detailed study of the eggs sheds new light on the phylogenetic position of alvarezsaurids within the Theropoda, and the evolution of eggs among Coelurosauria. We suggest thatplesiomorphic alvarezsaurids survived in Patagonia until the latest Cretaceous, whereas these basal forms became extinct elsewhere.
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| 2. |
- Alhalabi, Wafa A., et al.
(författare)
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Recovering lost time in Syria : New Late Cretaceous (Coniacian-Santonian) elasmosaurid remains from the Palmyrides mountain chain
- 2024
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Ingår i: Cretaceous research (Print). - : Elsevier. - 0195-6671 .- 1095-998X. ; 159
-
Tidskriftsartikel (refereegranskat)abstract
- Despite its relatively limited vertebrate fossil record, Syria currently records the largest number of documented Mesozoic marine reptile occurrences among the Middle Eastern countries. In particular, the phosphatic deposits of the Palmyrides mountain chain have yielded fossils of aquatic squamates, bothremydid and chelonioid marine turtles, as well as elasmosaurid plesiosaurs. Nevertheless, new discoveries have not been reported for the last two decades. Here, we describe the partial skeleton of an elasmosaurid plesiosaur from Syria, which comprises the middle and posterior cervical series, together with articulated pectoral, dorsal and anterior caudal parts of the vertebral column, with associated rib fragments. The fossil was excavated from Coniacian-Santonian phosphatic deposits of the Al Sawaneh el Charquieh mines, in the central part of the southwestern Palmyrides, about 200 km northeast of Damascus. The specimen can be assigned to Elasmosauridae based on the cervical centra morphology and, although incomplete, is significant because it not only represents likely the oldest, but also the currently most complete plesiosaur skeleton recovered from the Middle East. (c) 2024 Elsevier Ltd. All rights reserved.
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| 3. |
- Borinder, Niclas H., et al.
(författare)
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Reassessment of the earliest documented stegosaurian fossils from Asia
- 2016
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 68, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- In 1929, the famous Swedish palaeontologist Carl Wiman documented the first unequivocal stegosaurian dinosaur fossils from Asia. His material comprised an isolated dermal spine, together with a dorsal vertebra that was briefly described but never figured. Since then these remains have languished in obscurity, being noted in some stegosaur review articles but often ignored altogether. However, recent auditing of the Museum of Evolution palaeontological collection at Uppsala University in Sweden has led to the rediscovery of Wiman's original specimens, as well as two additional previously unrecognised stegosaurian dorsal vertebrae. All of these bones derive from the Lower Cretaceous (Berriasian-Valanginian) Mengyin Formation of Shandong Province in eastern China, and are morphologically compatible with the stratigraphically proximal stegosaurian taxon Wuerhosaurus from the Valanginian-Albian Tugulu Group in the Xinjiang Uyghur Autonomous Region of Western China. Wirnan's seminal stegosaurian fossils thus expand current palaeobiogeographical distributions, and contribute to the otherwise enigmatic record of Early Cretaceous stegosaurian occurrences.
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| 4. |
- Conte, Gabriele Larocca, et al.
(författare)
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Reassessment of a large lamniform shark from the Upper Cretaceous (Santonian) of Italy
- 2019
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 99, s. 156-168
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Tidskriftsartikel (refereegranskat)abstract
- To date, only a few partially articulated chondrichthyan specimens are known from the Upper Cretaceous marine fossil record of northern Italy. Here, we re-evaluate the taxonomic status and geological age of selachian remains originally discovered during the 19th century from the Castellavazzo locality. The described specimen is largely embedded in matrix with minute exposure of joined and moderately deformed sequentially stacked vertebral centra. Computed tomography (CT) image-data obtained of the specimen enabled the identification of potential cranial-cartilage elements located in close proximity to teeth and are here interpreted as remnants of the jaws. Based on tooth and vertebral morphology the specimen is in all likelihood an adult lamniform shark with a measured 3.5 m length. Using ordinary least-squares regression analysis (OLS) and proportion-based calculations, we estimated a total-length (TL) of 596.27 and 632.5-672.64 cm respectively. We prefer the size estimation derived through OLS bivariate regression; however, in the present analysis, reliance on a small sample size (n = 11) and evidence for differential scaling between taxa impose limitations on the precision of our size prediction. Planktonic foraminifera examined from the surrounding matrix of the slab preserving shark vertebral centra and teeth indicate a Santonian age (Dicarinella asymetrica zone). Although, the specimen could not confidently be assigned beyond the ordinal-level, the sheer centrum size, gross dental morphology, and depositional environment, are indicative of a pelagic apex-predator comparable to coeval lamniforms, with a specific resemblance towards cretoxyrhinids, reported from elsewhere along the peri-Tethyan shelf of Europe and Western Interior Seaway of North America. Finally, the re-emergence of this historical specimen, here re-described using cutting-edge techniques, is of great importance as it contributes to the otherwise poor record of extinct lamniform shark skeletons.
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| 5. |
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| 6. |
- Henriksson, Anders
(författare)
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Biochronology of the terminal Cretaceous calcareous nannofossil zone of Micula prinsii
- 1993
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 14:1, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- Seven Deep Sea Drilling Project (DSDP) sites, were examined in order to determine the chronology of the late Maastrichtian calcareous nannofossil Micula prinsii Zone. Six sites span the terminal Cretaceous palaeolatitudinal interval between 36°S and 37°N in the Atlantic ocean, and one site was from a palaeolatitude of 16°N in the Pacific Ocean. The M. prinsii Zone is often used to demonstrate the presence of terminal Cretaceous sediments. The chronology of the M. prinsii Zone is based on abundance counts and the base of this zone is correlated to the magnetic polarity stratigraphy. Micula prinsii first appeared near the base of subchron C29R. The estimated first appearance of M. prinsii is 0.25 ± 0.02 m.y. before the Cretaceous-Tertiary (K-T) boundary in the South Atlantic, 0.22 ± 0.02 m.y. before the K-T boundary in the North Atlantic and 0.19 ± 0.01 m.y. before the K-T boundary in the North Pacific. The M. prinsii Zone extends up to the K-T boundary, where its index species is among the Cretaceous calcareous nannofossil stock that became extinct. This zone is an important tool for verification of the completeness of terminal Maastrichtian sequences from low to middle latitudes.
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| 7. |
- Henriksson, Anders
(författare)
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Calcareous nannoplankton productivity and succession across the Cretaceous-Tertiary boundary in the Pacific (DSDP Site 465) and Atlantic (DSDP Site 527) oceans
- 1996
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 17:4, s. 451-477
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Tidskriftsartikel (refereegranskat)abstract
- The global extinctions linked to the Cretaceous-Tertiary (K-T) boundary severely affected marine pelagic organisms. The K-T boundary intervals at Deep Sea Drilling Project (DSDP) Site 527 (Leg 74) in the South Atlantic Ocean and Site 465 (Leg 62) in the Pacific Ocean were studied for changes in calcareous nannofossil assemblages from the late Maastrichtian to the early Paleocene. The sections analysed cover 180 kyr of the terminal Cretaceous and 200 kyr of the earliest Tertiary. Absolute and relative abundances of calcareous nannoplankton were calculated for both the entire flora and for individual species. No decrease in the number of species occurs towards the K-T boundary; relative and absolute abundances of different species are fairly stable throughout the terminal 180 kyr of the Cretaceous. At the K-T boundary the calcareous nannoflora shows a drastic and instantaneous decrease in absolute abundance. Typical Cretaceous species became extinct at the K-T boundary, but are present in the lowermost Tertiary as a result of bioturbation and reworking of the sediments. Very few species survived the K-T boundary. The species that occur sporadically in extremely low numbers in the Cretaceous, exhibit stable relative and absolute abundances through the lower Tertiary. Evolving Tertiary species appeared at the boundary and vary only moderately in absolute abundance through the lowermost Paleocene. The productivity of calcareous nannoplankton is determined here as the nannofossil accumulation rate (NFAR), which is suggested as an estimate of surface-water primary productivity. The terminal Cretaceous NFAR values were high and stable. At the K-T boundary the calcareous nannoflora suffered a 70-150-fold decrease in NFAR, indicating a catastrophic event. The Tertiary NFAR values remained low and fairly constant through the first 200 kyr. The productivity of calcareous nanno- plankton in the earliest Tertiary was dominated by the calcareous dinoflagellateThoracosphaerasp.
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| 8. |
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| 9. |
- Mendes, Mário Miguel, et al.
(författare)
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A Lower Cretaceous palynoflora from Carregueira (Lusitanian Basin, westernmost Iberia): taxonomic, stratigraphic and palaeoenvironmental implications
- 2022
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Ingår i: Cretaceous research (Print). - Amsterdam : Elsevier. - 0195-6671 .- 1095-998X. ; 130, s. 105036-105036
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe a new Lower Cretaceous palynoflora from the Lusitanian Basin, located in the westernmost sector of the Iberian Peninsula. The spore-pollen assemblage was extracted from samples collected in the Carregueira clay pit complex, located near the village of Juncal, western Portugal, from sedimentary deposits belonging to the Figueira da Foz Formation. A rich and well-preserved palynoflora, typical of non-marine fluvial environments, was recovered. Fifty-eight species and morphological groups of palynomorphs in 43 genera were recognized. The palynoflora is dominated by fern spores and conifer pollen. Angiosperm pollen is scarce and mainly represented by Afropollis, Clavatipollenites, Stellatopollis and Senectotetradites. Comparisons with described marine sections in Portugal suggest that the fossil horizon is lower Albian, corresponding to a hiatus between Zone I and Zone II in the Potomac Group of the eastern USA. The same beds contain a mesofossil flora dominated by angiosperm seeds, fruits and flowers. A similar contrast in the relative abundance of angiosperm mesofossils and pollen is seen at other Portuguese localities but is not evident in the Potomac Group. The palynoflora and the sedimentological data suggest deposition in wet lowland environments in a moderately humid regional setting.
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| 10. |
- Mendes, Mário Miguel, et al.
(författare)
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Battenispermum hirsutum gen.et sp. nov., a new Early Cretaceous seed from Portugal with chlamydospermousorganisation
- 2020
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Ingår i: Cretaceous research (Print). - Amsterdam : Elsevier. - 0195-6671 .- 1095-998X. ; 109
-
Tidskriftsartikel (refereegranskat)abstract
- A new genus and species, Battenispermum hirsutum, is described from the Early Cretaceous mesofossil flora of Catefica, Portugal. The new taxon is based on five ovulate structures with up to three seeds surrounded by an outer cup formed from partly fused bracts. The seeds are small, about 2.4–3.3 mm long and 1.0–1.6 mm wide, orthotropous with a chlamydospermous organisation. The nucellus is surrounded by a thin integument, a sclerenchymatic inner seed envelope and an additional outer envelope of four bracts, fused for most of their length. The seeds are three- or four-angled in transverse section and elliptical in lateral view with the free tips of the outer envelope forming short, apical projections around the micropyle. The outer surface of the inner seed envelope is almost smooth, while the abaxial surfaces of both inner and outer bracts of the compound ovulate structures are covered by a dense indumentum of long and stiff trichomes. Battenispermum hirsutum clearly belongs to the chlamydospermous BEG complex (Bennettitales-Erdtmanithecales-Gnetales), but it is distinguished from all previously described fossils by the presence of two distinct seed envelopes, a feature otherwise known only for extant Gnetum. The seeds of Battenispermum hirsutum differ, from those of extant Gnetum in other features, including the much simpler micropylar region.
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| 11. |
- O'Gorman, José P., et al.
(författare)
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The first non-aristonectine elasmosaurid (Sauropterygia; Plesiosauria) cranial material from Antarctica: new data on the evolution of the elasmosaurid basicranium and palate
- 2018
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Ingår i: Cretaceous research (Print). - : Elsevier. - 0195-6671 .- 1095-998X.
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Tidskriftsartikel (refereegranskat)abstract
- Elasmosaurids are a monophyletic group of cosmopolitan plesiosaurs with extremely long necks. Although abundant elasmosaurid material has been collected from the Upper Cretaceous of Antarctica, skull material is extremely rare. Here, new elasmosaurid cranial material from the lower Maastrichtian levels of the Cape Lamb Member (Snow Hill Island Formation) on Vega Island, Antarctica is described. The studied specimen (MLP 15-I-7-6) is a non-aristonectine elasmosaurid but shows a palate morphology characterized by the absence of a posterior interpterygoid symphysis and a posterior plate-like extension of the pterygoids, features previously associated with the aristonectine palatal structure. The specimen MLP 15-I-7-6 thus provides an indication that these palatal features are also present in non-aristonectine Weddellian elasmosaurids, and makes available additional evidence of the close phylogenetical relationship between the aristonectines and some Weddellian non-aristonectine elasmosaurids.
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| 12. |
- Pole, Mike, et al.
(författare)
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A new terrestrial Cretaceous-Paleogene site in New Zealand-turnover in macroflora confirmed by palynology
- 2009
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Ingår i: Cretaceous Research. - : Elsevier BV. - 0195-6671. ; 30:4, s. 917-938
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Tidskriftsartikel (refereegranskat)abstract
- A fluvial sequence near Cave Stream (north of Castle Hill Village, central Canterbury), New Zealand, contains organically-preserved plant macrofossils (cuticles). The almost ubiquitous presence of Araucariaceae macrofossils in the lower part of the section and their stratigraphic disappearance roughly coincident with the appearance of the angiosperm leaf Dryandra comptoniaefolia and conifer taxa only known elsewhere from sediments of Paleogene age, indicates that the section spans the Cretaceous-Paleogene (K-T) boundary. This was subsequently confirmed by a palynological study that demonstrated the disappearance of Late Cretaceous index species within the investigated exposure. The sequence supports the pattern recognized elsewhere in New Zealand where Araucariaceae macrofossils either disappear or become very rare in end-Cretaceous and the leaf Dryandra comptoniaefolia is an important component in the early Cenozoic. The Cave Stream K-T boundary is one of the very few in the world with organically-preserved plant macrofossils and confirms the dramatic turnover in macroflora, which is known from North America. (C) 2009 Elsevier Ltd. All rights reserved.
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| 13. |
- Poropat, Stephen F., et al.
(författare)
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Reassessment of coelurosaurian (Dinosauria, Theropoda) remains from the Upper Cretaceous Wangshi Group of Shandong Province, China
- 2013
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 45, s. 103-113
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Tidskriftsartikel (refereegranskat)abstract
- Non-avian theropods are well represented in the Cretaceous of Asia. However, the first theropod remains ever reported from China, from the Wangshi Group of Shandong Province, have not been reassessed since they were described by Carl Wiman in 1929, despite the great strides that have been made in theropod phylogenetics in the last eight decades. The remains redescribed herein consist of four vertebrae (two cervicals, one dorsal and one caudal) from one site, and a caudal vertebra and ungual phalanx from another. The vertebrae from the first site are assigned to tyrannosauroids and ornithomimosaurs, as is the caudal vertebra from the second site, whereas the manual ungual also bears resemblances to those of non-maniraptoran coelurosaurs (specifically compsognathids and ornithomimosaurs). Theropods remain relatively rare in the Wangshi Group; nevertheless, the remains redescribed herein highlight the potential for the discovery of more theropod remains in future excavations.
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| 14. |
- Reiss, Stefan, et al.
(författare)
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Filling the biostratigraphical gap : First choristoderan from the Lower - mid-Cretaceous interval of Europe
- 2019
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Ingår i: Cretaceous research (Print). - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 0195-6671 .- 1095-998X. ; 96, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- Choristodera is a Glade of extinct aquatic reptiles whose fossils have been found in freshwater and marginal marine deposits from Europe, Asia and North America. The European record is the most extensive, spanning at least the Middle Jurassic to early Miocene, and incorporates the stratigraphically oldest and youngest members of the group. Despite this, there is an unexplained-70 myr gap in European choristoderan fossil occurrences. Here we fill this hiatus with the discovery of an isolated choristoderan dorsal vertebra from the lower Cenomanian 'Rotkalk' red limestone facies of the Essen Greensand Formation in Wilhelm/Ruhr, North Rhine-Westphalia, western Germany. This specimen represents the first identifiable European choristoderan from the Kimmeridgian-Campanian interval, and displays a diagnostic state combination including an amphiplatyan centrum with synapophyses on the transverse processes that are level with the neurocentral suture. The palaeobiogeographical distribution of choristoderans thus likely transected the entire Laurasian landmass throughout the Cretaceous, with perceived stratigraphical interstices being a result of incomplete sampling.
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| 15. |
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| 16. |
- Rojas, Alexis, et al.
(författare)
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Early Cretaceous (Valanginian) brachiopods from the Rosablanca Formation, Colombia, South America : Biostratigraphic significance and paleogeographic implications
- 2019
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Ingår i: Cretaceous research (Print). - : Elsevier. - 0195-6671 .- 1095-998X. ; 96, s. 184-195
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Tidskriftsartikel (refereegranskat)abstract
- The Mesozoic fossil record of brachiopods in northern South America is relatively scarce and their biogeographical history is not well understood. Cretaceous brachiopods in this region are restricted to carbonate platforms of Colombia. Here we examine the brachiopod fauna from the middle part of the Rosablanca Formation near the town of Zapatoca, Eastern Cordillera of Colombia. We describe Sellithyris elizabetha nov. sp. combining traditional morphometrics and serial sectioning. This new terebratulide species shows morphological similarities with other species of the genus Sellithyris, including a Valanginian species from the ancient Gulf of Mexico. Using a semi-quantitative taphonomic analysis, we identified reworked specimens restricted to a single stratigraphic horizon, and consistent with a largescale erosional hiatus that may affect the biochronology of the Rosablanca Formation. In addition, phosphatic shells of the lingulide Lingularia sp. were recovered from two stratigraphic horizons and are valuable for local correlations. Although much of the material is fragmentary, it represents the oldest occurrences of Cretaceous lingulides in the region so far. Lingulide brachiopods have traditionally been considered as rare elements in Cretaceous near-shore marine communities, however, the material reported here suggests that they may have been common locally. (C) 2018 Elsevier Ltd. All rights reserved.
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| 17. |
- Sachs, Sven, et al.
(författare)
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Cranial osteology of the mid-Cretaceous elasmosaurid Thalassomedon haningtoni from the Western Interior Seaway of North America
- 2021
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Ingår i: Cretaceous Research. - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- Thalassomedon haningtoni is one of the most completely preserved elasmosaurid plesiosaurians described to date. Unlike most other elasmosaurid fossils, both the holotype and a second referred specimen — which were recovered from the middle Cenomanian Graneros Shale in the mid-western USA — are represented by intact skulls with articulated postcranial skeletons. Thalassomedon haningtoni thus constitutes an ideal ‘model elasmosaurid taxon’ that contributes significant character state data towards resolving contested relationships within the clade. Here, we present a detailed reassessment of the cranial osteology of T. haningtoni with the aim of evaluating its disputed species-level monophyly, together with its broader phylogenetic affinities. We identify several key diagnostic cranial traits including a sharply tapered premaxillary rostrum with a pronounced dorsomedian ridge that extends to the tip of the snout, a proportionately very small and rounded external bony nasal opening, and an anisodont functional dentition that incorporates a pair of enlarged ‘fangs’ in the second maxillary tooth position. Our phylogenetic analyses using first-hand scores unequivocally support classification of the Graneros Shale specimens as conspecific. Furthermore, consistent nesting with other North American elasmosaurid taxa suggests that T. haningtoni could evidence successive lineage divergences that took place within the Western Interior Seaway during the middle to latest Cretaceous.
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| 18. |
- Sachs, Sven, et al.
(författare)
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Enigmatic plesiosaur vertebral remains from the middle Turonian of Germany
- 2020
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Ingår i: Cretaceous research (Print). - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 0195-6671 .- 1095-998X. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- The Turonian (93.9-89.8 Ma) was a key transitional interval of plesiosaur evolution, during which pliosaurid apex predators (dominant since the Middle Jurassic) rapidly declined, and polycotylids correspondingly radiated as middle trophic-level pursuit hunters. Paradoxically, however, the fossil record of Turonian plesiosaurs is globally sparse, especially in continental Europe where only a handful of fragmentary specimens have been recovered from localities in the Czech Republic, Germany and Poland. Here, we report on a new European Turonian plesiosaur occurrence from the Bochum Grunsand Member of the Duisburg Formation in the city of Unna, western Germany. These remains comprise a series of eight mid-series cervical vertebrae with articulated ribs that can be precisely correlated to the lower middle Turonian UC8a-UC8b calcareous nannofossil biozones. The vertebrae display a distinctive character state combination, including transversely broad lozenge-shaped centra that are anteroposteriorly compact, bear amphicoelous articular surfaces, inset lateral sides, and large zygapophyses that are broader than the corresponding centra. Although phylogenetically inconclusive, these features are compatible with coeval polycotylids. The Bochum Grunsand Member vertebrae thus augment the currently scant knowledge of Turonian plesiosaurs from Europe, and support assertions that the regional assemblage was taxonomically diverse at that time.
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| 19. |
- Sachs, Sven, et al.
(författare)
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Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco
- 2017
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 74, s. 205-222
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Tidskriftsartikel (refereegranskat)abstract
- The holotype of Libonectes atlasense is an almost complete skeleton from Upper Cretaceous (mid-Turonian) rocks of the Goulmima area in eastern Morocco. Initial assessment of this specimen in 2005 proposed generic referral based on stratigraphical contemporaneity with Libonectes morgani from the Cenomanian-Turonian of Texas, U.S.A. Nevertheless, relative differences in the profile of the premaxillary-maxillary tooth row, position of the external bony nasal opening, number of teeth and rostrad inclination of the mandibular symphysis, proportions of the axial neural arch, and number of cervical and pectoral vertebrae were used to distinguish between these species. As part of an on-going comparative appraisal of elasmosaurid plesiosaurian osteo-anatomy, we re-examined the type and formally referred material of both L atlasense and L morgani in order to establish species validity, as well as compile a comparative atlas for use in future works. Our inspections revealed that these reportedly distinct species-level fossils are in fact virtually indistinguishable in gross morphology. Indeed, the only substantial difference occurs in relative prominence of the midline keel along the mandibular symphysis, which might be explained by intraspecific variation. Furthermore, our observations permit an amendment to the published generic diagnosis of Libonectes with the confirmation of important states such as the likely presence of a pectoral bar, distocaudad expansion of the humerus, and an epipodial foramen. In addition, novel features include a prominent 'prong-like' ventral midline process on the coracoids, and the development of a median pelvic bar that encloses a central fenestration. The composite remains of L morgani thus constitute one of the most complete elasmosaurid skeletal hypodigms documented worldwide, and evidence a trans-Atlantic distribution for this apparently dispersive species during the early Late Cretaceous.
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| 20. |
- Sachs, Sven, et al.
(författare)
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Turonian marine amniotes from the Opole area in southwest Poland
- 2018
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 84, s. 578-587
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Forskningsöversikt (refereegranskat)abstract
- 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 mosasauroid 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.
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| 21. |
- Schwarz-Wings, Daniela, et al.
(författare)
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Lower Cretaceous Mesoeucrocodylians from Scandinavia (Denmark and Sweden)
- 2009
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Ingår i: Cretaceous Research. - : Elsevier BV. - 0195-6671. ; 30:5, s. 1345-1355
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Tidskriftsartikel (refereegranskat)abstract
- The crocodyliform faunas of the lowermost Cretaceous Rabekke and Jydegard Formations on the Baltic island of Bornholm, Denmark, and the Annero Formation of Skane, southernmost Sweden, are represented by isolated teeth, osteoderms, and vertebrae. The rich Berriasian assemblage of the Rabekke Formation includes at least three distinctive taxa: Bernissartia sp., Theriosuchus sp., and Goniopholis sp., an association that is also known from several other contemporaneous European vertebrate localities. In contrast to this fauna, the Jydegard and Annero Formations have yielded only rare mesoeucrocodylian remains, which are assigned to Theriosuchus sp. and an undetermined mesoeucrocodylian taxon, possibly Pholidosaurus. Geographically, the Scandinavian localities represent the easternmost and northernmost distribution of typical continental Jurassic-Cretaceous crocodyliform communities in Europe. (C) 2009 Elsevier Ltd. All rights reserved.
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| 22. |
- Shevchuk, Olena, et al.
(författare)
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The first Cretaceous megaspores from Ukraine
- 2021
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Ingår i: Cretaceous research (Print). - Amsterdam : Elsevier. - 0195-6671 .- 1095-998X. ; 118, s. 104649-104649
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Tidskriftsartikel (refereegranskat)abstract
- The first megaspores recovered from Ukrainian Lower Cretaceous strata are described and illustrated by reflected light and scanning electron micrography. Four lycopsid megaspore taxa are identified in core samples from north of Kherson (Khersons'ka Oblast), in the Black Sea Basin, southern Ukraine. Miospore assemblages recovered from the same samples reveal a slightly higher diversity of lycopsid microspores and, in conjunction with previous foraminiferal biostratigraphy, indicate an Aptian-Albian age for the strata. The megaspore suite shares genera with mid-Mesozoic assemblages from widely distributed parts of the world, but most of the Ukrainian specimens have subtle morphological differences from congeneric forms established in other regions. The megaspores accumulated in fluvial floodplain facies and highlight the potential of this region for investigating other Cretaceous mesofossils including early flowers.
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| 23. |
- Solonin, Sergey, V, et al.
(författare)
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Late Cretaceous marine reptiles from Malyy Prolom in Ryazan Oblast, Central Russia
- 2021
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Ingår i: Cretaceous research (Print). - : Elsevier. - 0195-6671 .- 1095-998X. ; 127
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Tidskriftsartikel (refereegranskat)abstract
- During the Cenomanian-Turonian transition (similar to 94 Ma), what is today Central Russia formed part of the northern epicontinental margin of the Tethys Ocean. Diverse marine vertebrate faunas inhabited these palaeoenvironments, but their fossils are incompletely documented. Here, we report the discovery of marine reptile remains, recovered together with pterosaur, chondrichthyan, and actinopterygian fish material from a basal-most glauconitic sand and gravel layer of the Dmitrov Formation. These strata are exposed in an active quarry near the village of Malyy Prolom in the Shatsky District of Ryazan Oblast, Central Russia. The Dmitrov Formation deposits are middle-upper Santonian, but unconformably contact the underlying lower-middle Cenomanian Yakhroma Formation via a condensed boundary horizon that contains the vertebrate fossils with bivalve shell fragments and siliceous and phosphatic clasts. Such sedimentary characteristics indicate a high-energy shoreface setting where the vertebrate teeth and bones were likely reworked during cyclical regressions commencing in the latest Cenomanian-early Turonian. Time-averaging is also evidenced by the mixed occurrences of brachauchenine pliosaurids, elasmosaurid and polycotylid plesiosauroids, ophthalmosaurid ichthyosaurians similar to Pervush-ovisaurus, and a possible yaguarasaurine mosasauroid. These taxa are typical of Cenomanian-Turonian assemblages from across the northern peri-Tethys, and represent components of what were probably palaeobiogeographically widespread marine reptile faunas.
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| 24. |
- Sorensen, Anne Mehlin, et al.
(författare)
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Food resources and habitat selection of a diverse vertebrate fauna from the upper lower Campanian of the Kristianstad Basin, southern Sweden
- 2013
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Ingår i: Cretaceous Research. - : Elsevier BV. - 0195-6671. ; 42, s. 85-92
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Tidskriftsartikel (refereegranskat)abstract
- During the latest early Campanian, a diverse vertebrate assemblage inhabited the shallow coastal waters of the Kristianstad Basin, southernmost Sweden. The taxon-rich fauna includes numerous species of sharks, rays, chimaeroids, bony fish, mosasaurs, plesiosaurs, aquatic birds, crocodiles, and turtles. Vertebrate fossils have been found at several localities within the basin, representing at least three different environments: near-shore waters around a rocky island, presumably murky, shallow waters adjacent to a river mouth, and more open coastal waters. Many vertebrates in the marine faunal community were high-level predators, others were piscivorous, bottom-dwellers that fed primarily on benthic invertebrates and fish, or omnivores that fed on algae and invertebrates. The fauna thus exploited a wide range of food sources and habitats. Six trophic levels, ranging from primary producers to fifth-level consumers, are recognised, indicating a high loss of energy and reflecting a mixture of shallow coastal and more open water ecosystems. The trophic structure suggests that the basin was a rich palaeoenvironment with high faunal diversity and productivity. (c) 2013 Elsevier Ltd. All rights reserved.
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| 25. |
- Vajda, Vivi, et al.
(författare)
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A snapshot into the terrestrial ecosystem of an exceptionally well preserved dinosaur (Hadrosauridae) from the Upper Cretaceous of North Dakota, USA
- 2013
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Ingår i: Cretaceous research (Print). - Elsevier : Elsevier BV. - 0195-6671 .- 1095-998X. ; 46, s. 114-122
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Tidskriftsartikel (refereegranskat)abstract
- A palynological investigation of sedimentary rocks enclosing an exceptionally well-preserved fossil dinosaur (Hadrosauridae) discovered in the upper part of the Hell Creek Formation in south western North Dakota was conducted in order to document the immediate paleoenvironment of this dinosaur. The specimen, an Edmontosaurus annectens is remarkable in having exceptional three-dimensional preservation of soft tissue around the skeleton, indicating rapid burial. A well-preserved palynological assemblage dominated by fern and bryophyte spores, with lesser gymnosperm and angiosperm pollen was recovered. Sparse fresh-water algae and marine dinoflagellate cysts were also recorded. The palynofacies is dominated by wood fragments, including charcoal, with little amorphous organic matter. The presence of some typical pollen taxa of the Wodehouseia spinata Assemblage Zone including Striatellipollis striatellus, Tricolpites microreticulatus, Leptopecopites pocockii as well as a diverse suite of Aquilapollenites, is fully consistent with a Late Cretaceous (late Maastrichtian) age. The palynoflora indicates a local vegetation composed of a canopy of conifers dominated by Pinaceae and a minor sub-canopy of Taxodium and cycads, as well as an understory of hydrophilous ferns, mosses and herbaceous angiosperms, indicative of a warm and humid climate e an environment where this specific hadrosaur roamed over 66 million years ago.
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| 26. |
- Wanntorp, Livia, et al.
(författare)
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Past diversity of Proteaceae on subantarctic Campbell Island, a remote outpost of Gondwana
- 2011
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Ingår i: Cretaceous Research. - : Elsevier BV. - 0195-6671. ; 32:3, s. 357-367
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Tidskriftsartikel (refereegranskat)abstract
- Twelve fossil species of Proteaceous pollen, predominantly attributable to Proteacidites and Beaupreaidites, were recovered from the Maastrichtian-Paleocene sedimentary succession of the Garden Cove Formation on Campbell Island, the southernmost landmass of the Zealandia continent. Among these are two new species, Proteacidites campbellensis and Proteacidites hortisinus. The high diversity of Proteaceae pollen in the sediments encompassing the Cretaceous-Paleogene boundary on Campbell Island is consistent with the fossil record from neighbouring landmasses but strongly contrasts with the impoverished record of the family in the extant New Zealand flora. Examples of Beauprea- and Knightia-like pollen in the Campbell Island assemblages confirm the presence of these lineages on Zealandia by the end of the Cretaceous and suggest that their present endemism in New Caledonia and New Zealand can be explained in terms of relictual vicariant distributions, perhaps modified by northward tracking of warmer climates on Zealandia through the Cenozoic. (C) 2011 Elsevier Ltd. All rights reserved.
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