Maastrichtian representatives of the dragonfly family Aeschnidiidae question the entomofaunal turnover of the early Late Cretaceous

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
ANDRÉ NEL
Keyword(s):  
Late Cretaceous ◽  
Aquatic Insects ◽  
Fossil Record ◽  
Current Knowledge ◽  
Alternative Scenario ◽  
Family Level ◽  
Early Late ◽  
Freshwater Environments

Gaps in the fossil record are the major challenge for estimations of impacts of crises of biodiversity of the various clades. They can lead to important misinterpretations in the effects of the different events on the fauna and flora. It is especially the case for the end-Cretaceous, which is ‘near the midpoint of a 16-million-year gap in the insect fossil record’ (Schachat & Labandeira, 2021: 111). All the important Cretaceous insect Konzentrat Lagerstätten are before the Turonian. The analysis of Schachat et al. (2019) has reconstructed a massive loss of family-level diversity for the insects at the boundary Cretaceous-Cenozoic, a possible artefact due to this gap. An alternative scenario was that a turnover in the entomofauna occurred during the early Late Cretaceous in relation to the floristic changes of the Albian–Cenomanian (Nel et al., 2018). This turnover would have also affected the aquatic insects through important changes in the freshwater environments (Sinitshenkova & Zherikhin, 1996; Ivanov & Sukatsheva, 2002). The current knowledge on the odonatan fossil record suggests a pronounced turnover with the last records of several major clades during the Cenomanian-Turonian and first records of several modern ones during the same period (Nel et al., 2015). The widespread and very diverse Jurassic-Cretaceous family Aeschnidiidae is among the best examples of such extinctions supposed to have occurred after the Cenomanian, because of the absence of any fossil in younger strata.

A mid-Cretaceous angiosperm-dominated macroflora from the Cedar Mountain Formation of Utah, USA

2016 ◽  
Vol 90 (4) ◽  
pp. 640-662 ◽  
Author(s):  
Elisha B. Harris ◽  
Nan Crystal Arens
Keyword(s):  
Late Cretaceous ◽  
Coastal Plain ◽  
Fossil Record ◽  
Leaf Mass Per Area ◽  
Coastal Plains ◽  
Detailed Report ◽  
Cedar Mountain Formation ◽  
Ecological Evolution ◽  
The Tropics ◽  
Early Late

AbstractAngiosperms first appeared in the fossil record as pollen during the Valanginian–Hauterivian; they spread out of the tropics in the Aptian and Albian, and radiated in the Late Cretaceous. Despite these general patterns, details of the taxonomic, geographic, and ecological evolution of Cretaceous angiosperms are relatively poorly known because only a handful of Early and mid-Cretaceous macrofloras have been reported. This is the first detailed report of a fossil leaf flora from the Cedar Mountain Formation from the mid-Cretaceous of the Western Interior. We describe a flora that is overwhelmingly dominated by angiosperms (152 of 153 identified specimens are angiosperms) from the Albian–Cenomanian transition that is preserved in a clay- and carbonate-rich, lacustrine mudstone from the uppermost Cedar Mountain Formation of Emery County, Utah. We recognize 18 leaf morphotypes, all of which are dicotyledonous angiosperms. The majority of the Cedar Mountain morphotypes have taxonomic affinities with forms of similar age described from the Atlantic and Gulf coastal plains and other localities from the Western Interior. From this, we infer that a relatively diverse angiosperm flora grew along the margins of a small pond on the coastal plain. Palynological preparations of the fossil matrix were barren; however, previous studies of other facies within the formation showed that both conifers and ferns were important components of the regional vegetation during Cedar Mountain time. The effective absence of conifers and ferns in this macroflora and low leaf mass per area values among the angiosperms measured suggests that even at the Early–Late Cretaceous transition, angiosperms had come to dominate some sites, particularly those that were disturbed or seasonally ephemeral, where fast-growth or seasonal deciduousness would have been favored.

scholarly journals Dinosaurs from the Santonian–Campanian Atlantic coastline substantiate phylogenetic signatures of vicariance in Cretaceous North America

2021 ◽  
Vol 8 (8) ◽  
pp. 210127
Author(s):  
Chase Doran Brownstein
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Coastal Plain ◽  
Fossil Record ◽  
Atlantic Coastal Plain ◽  
Terrestrial Vertebrates ◽  
Small Juvenile ◽  
The Poor ◽  
Atlantic Coastal ◽  
Early Late

During the Cretaceous, diversifications and turnovers affected terrestrial vertebrates experiencing the effects of global geographical change. However, the poor fossil record from the early Late Cretaceous has concealed how dinosaurs and other terrestrial vertebrates responded to these events. I describe two dinosaurs from the Santonian to Early Campanian of the obscure North American paleolandmass Appalachia. A revised look at a large, potentially novel theropod shows that it likely belongs to a new clade of tyrannosauroids solely from Appalachia. Another partial skeleton belongs to an early member of the Hadrosauridae, a highly successful clade of herbivorous dinosaurs. This skeleton is associated with the first small juvenile dinosaur specimens from the Atlantic Coastal Plain. The tyrannosauroid and hadrosaurid substantiate one of the only Late Santonian dinosaur faunas and help pinpoint the timing of important anatomical innovations in two widespread dinosaur lineages. The phylogenetic positions of the tyrannosauroid and hadrosaurid show Santonian Appalachian dinosaur faunas are comparable to coeval Eurasian ones, and the presence of clades formed only by Appalachian dinosaur taxa establishes a degree of endemism in Appalachian dinosaur assemblages attributable to episodes of vicariance.

Large predatory marine reptiles from the Albian–Cenomanian of Annopol, Poland

2015 ◽  
Vol 153 (1) ◽  
pp. 1-16 ◽  
Author(s):  
NATHALIE BARDET ◽  
VALENTIN FISCHER ◽  
MARCIN MACHALSKI
Keyword(s):  
Late Cretaceous ◽  
Current Knowledge ◽  
Marine Ecosystems ◽  
Marine Reptiles ◽  
Marine Reptile ◽  
Early Late ◽  
Temporal Extent

AbstractDuring the Early–Late Cretaceous transition, marine ecosystems in Eurasia hosted a diverse set of large predatory reptiles that occupied various niches. However, most of our current knowledge of these animals is restricted to a small number of bonebed-like deposits. Little is known of the geographical and temporal extent of such associations. The middle Albian – middle Cenomanian phosphorite-bearing succession exposed at Annopol, Poland produces numerous ichthyosaurian and plesiosaurian fossils. These are mostly isolated skeletal elements (e.g. teeth, vertebrae), but disarticulated partial skeletons and an articulated, subvertically embedded ichthyosaur skull are also available. The following taxa are identified: ‘Platypterygius’ sp., cf. Ophthalmosaurinae, Ichthyosauria indet.,Polyptychodon interruptus, Pliosauridae indet., Elasmosauridae indet. and Plesiosauria indet. The large-sized ichthyosaur ‘Platypterygius’ and the pliosauridPolyptychodon interruptuspredominate within the upper Albian – middle Cenomanian deposits. The Annopol record, combined with data from England, France and western Russia, suggests that ‘Platypterygius’ andPolyptychodon interruptusformed a long-term, stable ecological sympatry in marine ecosystems of the European archipelago, at least during the Albian – middle Cenomanian. In addition, the marine reptile assemblage from Annopol is distinct from other Eurasian ecosystems in containing also elasmosaurids in its Albian portion.

scholarly journals Isolated pliosaurid teeth from the Albian–Cenomanian (Cretaceous) of Annopol, Poland

2017 ◽  
Vol 67 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Daniel Madzia ◽  
Marcin Machalski
Keyword(s):  
Cross Section ◽  
Late Cretaceous ◽  
Type Species ◽  
Late Jurassic ◽  
Morphological Variability ◽  
Original Material ◽  
Tooth Crown ◽  
Similar Morphology ◽  
Faunal Turnover ◽  
Early Late

AbstractBrachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic- Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian-middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.

scholarly journals Depositional setting and limiting factors of early Late Cretaceous glaucony formation: implications from Cenomanian glauconitic strata (Elbtal Group, Germany)

Facies ◽  
2021 ◽  
Vol 67 (3) ◽  
Author(s):  
Markus Wilmsen ◽  
Udita Bansal
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Time Scales ◽  
Late Cretaceous ◽  
Limiting Factors ◽  
High Accumulation ◽  
Spatio Temporal ◽  
Facies Types ◽  
Facies Succession ◽  
Early Late

AbstractCenomanian strata of the Elbtal Group (Saxony, eastern Germany) reflect a major global sea-level rise and contain, in certain intervals, a green authigenic clay mineral in abundance. Based on the integrated study of five new core sections, the environmental background and spatio-temporal patterns of these glauconitic strata are reconstructed and some general preconditions allegedly needed for glaucony formation are critically questioned. XRD analyses of green grains extracted from selected samples confirm their glauconitic mineralogy. Based on field observations as well as on the careful evaluation of litho- and microfacies, 12 glauconitc facies types (GFTs), broadly reflecting a proximal–distal gradient, have been identified, containing granular and matrix glaucony of exclusively intrasequential origin. When observed in stratigraphic succession, GFT-1 to GFT-12 commonly occur superimposed in transgressive cycles starting with the glauconitic basal conglomerates, followed up-section by glauconitic sandstones, sandy glauconitites, fine-grained, bioturbated, argillaceous and/or marly glauconitic sandstones; glauconitic argillaceous marls, glauconitic marlstones, and glauconitic calcareous nodules continue the retrogradational fining-upward trend. The vertical facies succession with upwards decreasing glaucony content demonstrates that the center of production and deposition of glaucony in the Cenomanian of Saxony was the nearshore zone. This time-transgressive glaucony depocenter tracks the regional onlap patterns of the Elbtal Group, shifting southeastwards during the Cenomanian 2nd-order sea-level rise. The substantial development of glaucony in the thick (60 m) uppermost Cenomanian Pennrich Formation, reflecting a tidal, shallow-marine, nearshore siliciclastic depositional system and temporally corresponding to only ~ 400 kyr, shows that glaucony formation occurred under wet, warm-temperate conditions, high accumulation rates and on rather short-term time scales. Our new integrated data thus indicate that environmental factors such as great water depth, cool temperatures, long time scales, and sediment starvation had no impact on early Late Cretaceous glaucony formation in Saxony, suggesting that the determining factors of ancient glaucony may be fundamentally different from recent conditions and revealing certain limitations of the uniformitarian approach.

Radiolarian assemblages of Middle and Late Jurassic to early Late Cretaceous (Cenomanian) ages from an olistolith record pelagic deposition within the Bornova Flysch Zone in western Turkey

2012 ◽  
Vol 183 (4) ◽  
pp. 307-318 ◽  
Author(s):  
Ugur Kagan Tekin ◽  
M. Cemal Göncüoglu ◽  
Seda Uzuncimen
Keyword(s):  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Western Turkey ◽  
Oceanic Basin ◽  
Platform Margin ◽  
Lowermost Part ◽  
Early Late ◽  
Radiolarian Assemblages

Abstract The Bornova Flysch Zone (BFZ) in NW Anatolia comprises several olistoliths or tectonic slivers, representing various parts of the Izmir-Ankara ocean. Radiolarian assemblages extracted from one of the olistoliths of the BFZ, cropping out along the Sögütlü section, to the NE Manisa city, were studied in detail. The lowermost part of the section contains latest Bajocian – early Callovian radiolarian taxa, followed by radiolarian assemblages indicating Late Jurassic to early Late Cretaceous (Cenomanian) ages. Previous studies reveal that the Izmir-Ankara oceanic basin was initially opened during late Ladinian – early Carnian. The new radiolarian data obtained from this olistolith reveals that relatively condensed, and possibly more or less continuous, pelagic sedimentation took place during the late Middle Jurassic to early Late Cretaceous in a non-volcanic oceanic basin closer to the Tauride-Anatolide platform margin.

An early Late Cretaceous (Cenomanian) sturgeon (Acipenseriformes) from the Dunvegan Formation, northwestern Alberta, Canada

2014 ◽  
Vol 51 (7) ◽  
pp. 677-681 ◽  
Author(s):  
Matthew J. Vavrek ◽  
Alison M. Murray ◽  
Phil R. Bell
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Recent Survey ◽  
Peace River ◽  
Northern Regions ◽  
Early Late

A recent survey of the middle Cenomanian Dunvegan Formation along the Peace River, Alberta, has yielded a partial skull of a large acipenseriform fish. The fossil was from an animal approximately 5 m in length, based on comparisons with living relatives. Though incomplete, this represents an important record of mid-Cretaceous fish from northern North America, as formations of this age are virtually unexplored in northern regions. This fossil is the oldest acipenserid from North America, and one of the most northerly known.

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

2010 ◽  
Vol 57 (5) ◽  
pp. 391-412 ◽  
Author(s):  
L. Cavin ◽  
H. Tong ◽  
L. Boudad ◽  
C. Meister ◽  
A. Piuz ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Early Late

scholarly journals Otomorphs (= otocephalans or ostarioclupeomorphs) revisited

2018 ◽  
Vol 16 (3) ◽  
Author(s):  
Gloria Arratia
Keyword(s):  
Fossil Record ◽  
Morphological Character ◽  
Neotropical Region ◽  
Morphological Features ◽  
Heterogeneous Group ◽  
Vertebral Centra ◽  
Molecular Studies ◽  
Gas Bladder ◽  
Parietal Bones ◽  
Freshwater Environments

ABSTRACT A morphological revision is presented here on the cohort Otomorpha, a clade currently interpreted as the most primitive among the large supercohort Clupeocephala. Otomorpha is a morphologically heterogeneous group represented by clupei forms , alepocephaliforms, and ostariophysans (gonorynchiforms, cypriniforms, characiforms, siluriforms, and gymnoti forms) that inhabit various marine and freshwater environments worldwide. Otomorphs have a long (ca. 145 Ma) and diverse fossil record. They are the largest fish teleostean clade worldwide, as well as the largest of the Neotropical Region. While molecular studies strongly confirm the monophyly of Otomorpha, most potential morphological synapomorphies of the group become homoplastic largely due to the peculiar morphological character states (either losses or transformations) present in alepocephaliforms. The fusion of haemal arches with their respective vertebral centra anterior to preural centrum 2 stands as an unambiguous synapomorphy of the clade. The ankylosis or fusion of the extrascapular and parietal bones, and silvery areas associated with the gas bladder are also interpreted as synapomorphies, although they are homoplastic characters mainly due to secondary losses or further transformations of the morphological features in the alepocephaliforms.

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