scholarly journals An ichthyosaur (Reptilia: Ichthyosauria) specimen from the Lower Cretaceous (Berriasian) Spilsby Sandstone Formation of Nettleton, Lincolnshire, UK

2017 ◽  
Author(s):  
John P. Green ◽  
Dean Lomax
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Sandstone Formation

A fragmentary ichthyosaur specimen collected in situ at Castle Top Quarry in Nettleton, Lincolnshire, UK from exposures of the Lower Cretaceous (Berriasian) Spilsby Sandstone Formation (Subcraspedites ?preplicomphalus Zone) is reported. In general, Early Cretaceous ichthyosaurs from the Berriasian to Barremian are poorly understood. Despite the fragmentary nature of the described specimen, it is the first ichthyosaur reported from this specific zone and adds to the literature another rare ichthyosaur from the Berriasian.

Skeletal reconstruction and life restoration of Sauropelta (Ankylosauria: Nodosauridae) from the Cretaceous of North America

1984 ◽  
Vol 21 (12) ◽  
pp. 1491-1498 ◽  
Author(s):  
Kenneth Carpenter
Keyword(s):  
British Columbia ◽  
North America ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Foot Morphology ◽  
Skeletal Reconstruction

A skeletal reconstruction and life restoration are presented for the Early Cretaceous nodosaurid ankylosaur Sauropelta edwardsi. This composite is based on several partial skeletons having armor preserved in situ from the Lower Cretaceous Cloverly Formation of Wyoming and Montana. Comparison of foot morphology with that of the ichnofossil Tetrapodosaurus borealis, from the Lower Cretaceous Gething Formation of British Columbia, suggests that the footprint is that of Sauropelta. A hypothesis is presented suggesting that most ankylosaurs are found on their backs because of bloating.

scholarly journals Convergent evolution of ramified antennae in insect lineages from the Early Cretaceous of Northeastern China

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161448 ◽  
Author(s):  
Taiping Gao ◽  
Chungkun Shih ◽  
Conrad C. Labandeira ◽  
Jorge A. Santiago-Blay ◽  
Yunzhi Yao ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Motion Detection ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
Convergent Evolution ◽  
Chemical Cues ◽  
Northeastern China ◽  
Environmental Cues ◽  
Key Innovation ◽  
Temperature Levels

Antennae are important, insect sensory organs that are used principally for communication with other insects and the detection of environmental cues. Some insects independently evolved ramified (branched) antennae, which house several types of sensilla for motion detection, sensing olfactory and chemical cues, and determining humidity and temperature levels. Though ramified antennae are common in living insects, occasionally they are present in the Mesozoic fossil record. Here, we present the first caddisflies with ramified antennae, the earliest known fossil sawfly, and a scorpionfly also with ramified antennae from the mid-Lower Cretaceous Yixian Formation of Northeastern China, dated at 125 million years ago (Ma). These three insect taxa with ramified antennae consist of three unrelated lineages and provide evidence for broad structural convergence that historically has been best demonstrated by features such as convergent mouthparts. In addition, ramified antennae in these Mid-Mesozoic lineages likely do not constitute a key innovation, as they are not associated with significantly increased diversification compared with closely related lineages lacking this trait, and nor are they ecologically isolated from numerous, co-occurring insect species with unmodified antennae.

New multituberculate mammal from the Early Cretaceous of eastern North America

2013 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Richard L. Cifelli ◽  
Cynthia L. Gordon ◽  
Thomas R. Lipka
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Early Cretaceous ◽  
North American ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Relative Length ◽  
Central Position ◽  
Eastern North America ◽  
The North

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

Palaeoenvironmental significance of storm coquinas in a Lower Cretaceous coastal lagoonal succession (Vectis Formation, Isle of Wight, southern England)

2000 ◽  
Vol 137 (2) ◽  
pp. 193-205 ◽  
Author(s):  
JONATHAN D. RADLEY ◽  
MICHAEL J. BARKER
Keyword(s):  
High Resolution ◽  
Principal Components ◽  
Lower Cretaceous ◽  
Coastal Lagoons ◽  
Trace Fossils ◽  
Isle Of Wight ◽  
Southern England ◽  
Desiccation Cracks ◽  
Stratigraphic Framework

Thin bioclastic limestone beds (‘coquinas’) in the Vectis Formation (Wealden Group, Lower Cretaceous) of the Isle of Wight, southern England, exhibit a range of biofabrics and internal stratigraphies. These features are attributed to both simple and complex storm deposition of allochthonous biogenic and siliciclastic materials in coastal lagoons and on adjacent mudflats. These modes of deposition facilitated preservation of dinosaur trackways, desiccation cracks, shallow-tier trace fossils and in situ bivalve colonies through rapid burial. The coquinas thus preserve a record of surficial muds, commonly lost through reworking. The principal components of the coquinas comprise dispersed elements from within the argillaceous ‘background’ facies. Some of these beds are laterally traceable for up to 27 km, providing the foundations for a high-resolution event-stratigraphic framework.

A new assemblage of Early Cretaceous green lacewings (Chrysopidae: Neuroptera) from Transbaikalia

2016 ◽  
Vol 107 (2-3) ◽  
pp. 195-202 ◽  
Author(s):  
Alexander V. Khramov
Keyword(s):  
New Species ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
New Genus ◽  
Green Lacewings

ABSTRACTOne new genus and four new species of Chrysopidae are described from the Lower Cretaceous of Khasurty, Transbailakia (Russia):Mesypochrysa cannabinasp. nov.;M. naranicasp. nov.;Aberrantochrysa buryaticagen. & sp. nov.; andA. pulchellagen. & sp. nov. The abundance of Chrysopidae in Mesozoic localities is discussed.

Early Cretaceous redbeds from the Minle Basin, Hexi Corridor, northwest China: Mineralogy and geochemistry implications for paleoweathering, provenance, and tectonic settings

2019 ◽  
Vol 7 (2) ◽  
pp. T525-T545
Author(s):  
Yaxiong Sun ◽  
Wenlong Ding ◽  
Yang Gu ◽  
Gang Zhao ◽  
Siyu Shi ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Chemical Weathering ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Northwest China ◽  
Hexi Corridor ◽  
Sediment Supply ◽  
Compositional Variation ◽  
Tectonic Settings

Redbeds with a large thickness in the lower Cretaceous record abundant geologic information in the Minle Basin. We have conducted the paleoweathering conditions, provenance, and tectonic settings based on mineralogy and geochemistry. Our results indicate that mudstone samples are characterized by abundant illite with negligible amounts of K-feldspars and analcime. The lower part of the lower Cretaceous is rich in quartz, whereas the upper part is dominated by dolomite and analcime. We suggest that this is caused by the decreasing input of the clastic influx during the middle-late early Cretaceous. High index of compositional variation values (average 1.33) indicate first-cycle sediment supply, suggesting an overall compositional immaturity and short-distance transportation. These characteristics are consistent with an active regional extension tectonic setting. The [Formula: see text] system ([Formula: see text];[Formula: see text];[Formula: see text]) and Th/U versus Th consistently reveal that the lower Cretaceous experienced a positive gradient in chemical weathering from young to old formations. Although the patterns of trace elements in three formations of the lower Cretaceous are different, those of the rare earth elements (REEs) tend to be consistent. The significant enrichment of light REEs, heavy REEs fractionation, and distinctive negative Eu anomalies suggest derivation from an old, upper continental crust composed of predominantly felsic sediments. This interpretation is supported by several discrimination diagrams such as titanium dioxide-nickel ([Formula: see text]), which shows the characteristics of immature recycled sediments. A few sensitive elements, ratios, and normalized REE patterns indicate a provenance of an active continental margin and a continental island arc (CIA). The La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 discrimination plots further confirm the CIA signature. Thus, we conclude that the early Cretaceous redbeds in the Minle Basin, Hexi Corridor, were deposited in a dustpan-shaped half-graben basin in a CIA setting when northwest China was influenced by intense regional extension.

New record of Tettigarctidae (Insecta, Hemiptera, Cicadoidea) from the Lower Cretaceous of Brazil

Zootaxa ◽  
2005 ◽  
Vol 1087 (1) ◽  
pp. 53 ◽  
Author(s):  
FEDERICA MENON
Keyword(s):  
Southern Hemisphere ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
New Record ◽  
New Genus ◽  
New Genus And Species ◽  
New Discovery

Tettagalma striata, new genus and species of Tettigarctidae (Hemiptera: Cicadoidea), is described from the Lower Cretaceous laminated limestones of the Crato Formation, Brazil. The new discovery represents the first certain record of this family in Brazil and confirms its presence in the Southern Hemisphere during the early Cretaceous. Architettix Hamilton, 1990, from the same formation, and all the taxa originally placed in Cicadoprosbolidae, are also included in Tettigarctidae, as the former is considered a synonym.

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