scholarly journals Morphometric changes in two Late Cretaceous calcareous nannofossil lineages support diversification fueled by long-term cooling

2020 ◽  
Author(s):  
mohammad javad razmjooei ◽  
Nicolas Thibault ◽  
Anoshiravan Kani
Keyword(s):  
New Species ◽  
Climate Variability ◽  
Late Cretaceous ◽  
Calcareous Nannofossil ◽  
The Core ◽  
Two New Species ◽  
Climatic Evolution ◽  
Biometric Measurements

Biometric measurements undertaken on two relevant taxa, Cribrosphaerella and Microrhabdulus, make the core of this chapter. The results of this paper allowed us to describe two new species of Microrhabdulus and suggest that the peculiar climatic evolution across the Campanian and Maastrichtian triggered a rise in diversity and size of nannofossils following both Cope’s and Bergmann’s rules and its possible effects on the morphometric changes of Cribrosphaerella and Microrhabdulus. In this study, the link between climate variability and diversification has been discussed, and two new species of Microrhabdulus are described.

scholarly journals Morphometric changes in two Late Cretaceous calcareous nannofossil lineages support diversification fueled by long-term cooling

2020 ◽  
Author(s):  
mohammad javad razmjooei ◽  
Nicolas Thibault ◽  
Anoshiravan Kani
Keyword(s):  
New Species ◽  
Climate Variability ◽  
Late Cretaceous ◽  
Calcareous Nannofossil ◽  
The Core ◽  
Two New Species ◽  
Climatic Evolution ◽  
Biometric Measurements

Biometric measurements undertaken on two relevant taxa, Cribrosphaerella and Microrhabdulus, make the core of this paper. The results of this paper allowed us to describe two new species of Microrhabdulus and suggest that the peculiar climatic evolution across the Campanian and Maastrichtian triggered a rise in diversity and size of nannofossils following both Cope’s and Bergmann’s rules and its possible effects on the morphometric changes of Cribrosphaerella and Microrhabdulus. In this study, the link between climate variability and diversification has been discussed, and two new species of Microrhabdulus are described.

Late Santonian megaspore floras from the Gulf Coastal Plain (Georgia, USA)

2011 ◽  
Vol 85 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Richard Lupia
Keyword(s):  
New Species ◽  
North America ◽  
Late Cretaceous ◽  
Coastal Plain ◽  
Eastern North America ◽  
Gulf Coastal Plain ◽  
Two New Species ◽  
Western Interior Basin ◽  
Heterosporous Ferns

Fossil megaspore floras from the Late Cretaceous of North America have been studied extensively, but primarily from the Western Interior Basin. Two new megaspore floras are described from eastern North America along the Gulf Coastal Plain. Cumulatively, 10 genera and 16 species of megaspores are recognized from Allon, Georgia and along Upatoi Creek, Georgia (both late Santonian in age, ~84 Ma). Megaspores identified have affinities to both heterosporous lycopsids, e.g., Erlansonisporites, Minerisporites, and Paxillitriletes, and to heterosporous ferns, e.g., Ariadnaesporites, and Molaspora. Lycopsid megaspores are more diverse than fern megaspores in the Allon and the Upatoi Creek floras. Two new species—Erlansonisporites confundus n. sp. and Erlansonisporites potens n. sp.—are proposed.

scholarly journals Calcareous nannofossil assemblages of the Late Cretaceous Fiqa Formation, north Oman

2019 ◽  
Vol 38 (1) ◽  
pp. 25-54
Author(s):  
Zainab Al Rawahi ◽  
Tom Dunkley Jones
Keyword(s):  
Late Cretaceous ◽  
Side Wall ◽  
Inverse Correlation ◽  
Hydrocarbon Exploration ◽  
High Fertility ◽  
Calcareous Nannofossil ◽  
Fine Grained ◽  
Taxonomic Description ◽  
Main Components

Abstract. This study presents the first detailed calcareous nannofossil assemblage data from the Late Cretaceous succession of the subsurface Aruma Basin, north Oman. The taxonomic description and documentation of assemblage composition are based on extensive quantitative analysis of ditch cuttings and side-wall samples from eight hydrocarbon exploration wells across north Oman. The samples studied from those wells cover the Coniacian to earliest Maastrichtian deep marine shales and marls of the subsurface Fiqa Formation. These fine-grained siliciclastic deposits often yield moderately to well-preserved nannofossil assemblages, especially in the Campanian intervals. Consequently, diverse assemblages have been recorded from the Fiqa Formation, with a total diversity of ∼200 species, including two new species, Staurolithites ormae sp. nov. and Chiastozygus fahudensis sp. nov., which are illustrated and described. Extensive imaging of this diversity is provided here, as are stratigraphic distributions of the main components from a key reference well in north Oman, W-4. Poorly described groups such as Staurolithites are closely investigated and their utility for stratigraphic applications is highlighted. Relative abundances of nannofossil taxa with strong palaeoenvironmental preferences have revealed new insights into the palaeo-productivity of the basin. High-fertility species like Discorhabdus ignotus, Biscutum constans and Zeugrhabdotus erectus show substantial variations in abundance throughout the Fiqa Formation, reflecting long-term shifts in the productivity conditions of the basin. This is supported by abundance patterns of Watznaueria barnesiae and Micula staurophora that show a broadly inverse correlation with the high-fertility species. The Fiqa Formation represents a key regional seal unit for the Cretaceous hydrocarbon reservoirs of Oman, as well as being a productive unit elsewhere in the Arabian Peninsula. Beyond the Aruma Basin of Oman, this study will provide a key reference point for future biostratigraphic or palaeoenvironmental analyses of the Late Cretaceous calcareous nannofossil assemblages across the Middle East and other southern Tethyan areas.

scholarly journals Two new species of the genus Archaeopolycentra (Trichoptera: Polycentropodidae) from Cretaceous Taimyr amber

2021 ◽  
Vol 444 ◽  
pp. 1-7
Author(s):  
S.I. Melnitsky ◽  
◽  
V.D. Ivanov ◽  
Keyword(s):  
New Species ◽  
Late Cretaceous ◽  
The Family ◽  
Two New Species

Two new caddisfly species Archaeopolycentra turvalsia sp. n. and Archaeopolycentra achupomotet sp. n. (Polycentropodidae) from Late Cretaceous Taymyr amber (Santonian, Kheta Formation, 85 Ma) are described and illustrated. Totally, now the list of caddisflies from Taymyr amber includes 13 species, and the family Polycentropodidae is represented by five species.

Two new species of the Clubiona corticalis-group from Guizhou Province, China (Araneae: Clubionidae) 

Zootaxa ◽  
2018 ◽  
Vol 4415 (2) ◽  
pp. 393
Author(s):  
JIANSHUANG ZHANG ◽  
HAO YU ◽  
YANG ZHONG
Keyword(s):  
New Species ◽  
Species Composition ◽  
Guizhou Province ◽  
Core Group ◽  
The Core ◽  
Two New Species ◽  
Species Groups ◽  
High Diversity

Clubiona Latreille, 1804, the largest genus in family Clubionidae, currently includes 495 species worldwide with 126 species from China (Li & Lin 2016; World Spider Catalog 2018). Due to the high diversity in Clubiona, several subgenera and species-groups have been proposed (Wang et al. 2015). While there is no agreement on the limits of most species-groups of Clubiona (Deeleman-Reinhold 2001), the corticalis-group has been widely considered as putatively monophyletic. The group presents a distinct set of characters (Mikhailov 1995; Deeleman-Reinhold 2001; Liu et al. 2016) and the species composition of the core-group is relatively stable (Mikhailov 1995; Deeleman-Reinhold 2001; Dankittipakul & Singtripop 2008; Wu et al. 2015). At least two generic names are available for the corticalis-group, Atalia Thorell, 1887 and Paraclubiona Lohmander, 1944 (Mikhailov 2012). Spiders of the corticalis-group are well studied in China and several new species have been described in recent years (Yu et al. 2012; Zhu et al. 2012; Wang et al. 2015; Wu et al. 2015; Liu et al. 2016; He et al. 2016). Up to now, the Clubiona corticalis-group has more than 28 Chinese species (Wang et al. 2015; Wu et al. 2015; Liu et al. 2016; He et al. 2016; Yu et al. 2017), making it one of the most well known clubionid groups in China. While examining spiders collected from Guizhou Province, China, we came across some specimens from the Clubiona corticalis-group, which are described here as belonging to two new species. 

scholarly journals Two new species in the Micarea prasina group from Western Europe

2017 ◽  
Vol 49 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Pieter P. G. VAN DEN BOOM ◽  
A. Maarten BRAND ◽  
Brian J. COPPINS ◽  
Emmanuël SÉRUSIAUX
Keyword(s):  
New Species ◽  
The Netherlands ◽  
Western Europe ◽  
Anatomical Studies ◽  
Core Group ◽  
The Core ◽  
Two New Species ◽  
Gyrophoric Acid

AbstractDetailed morphological and anatomical studies informed by molecular inferences with mtSSU as a marker revealed two new species of Micarea in Western Europe, both belonging to the core group of the genus, namely the M. prasina group: M. herbarum from the Netherlands and Poland and M. meridionalis from Portugal and Italy. Micarea herbarum looks like a small or depauperate M. denigrata but clearly differs by the lack of gyrophoric acid, while M. meridionalis is distinguished by its granular thallus and the production of micareic acid.

Ordovician geology of Akpatok Island, Ungava Bay, District of Franklin

1976 ◽  
Vol 13 (1) ◽  
pp. 157-178 ◽  
Author(s):  
Robert H. Workum ◽  
Thomas E. Bolton ◽  
Christopher R. Barnes
Keyword(s):  
New Species ◽  
Carbonate Rocks ◽  
Drill Hole ◽  
Hudson Bay ◽  
Similar Sequence ◽  
The West ◽  
The Core ◽  
Two New Species ◽  
Conodont Fauna ◽  
Early Upper

The Paleozoic sequence of Akpatok Island consists of a least 800 ft ([Formula: see text]) of exposed limestone, underlain by 1098 ft (334.7 m) of limestone, shale, and sandstone, as recognized in Premium Homestead Akpatok L-26 drill hole located on the west-central coast. The exposed carbonate rocks contain a megafaunal sequence and a limited conodont fauna ranging in age from late Middle (Barneveld) to early Upper (Maysvillian) Ordovician; a similar sequence is present within the upper Bad Cache Rapids – Churchill River Groups of Southampton Island, Hudson Bay. A conodont fauna present in the core 119 to 231 ft (36.3–70.4 m) above the Precambrian is of early Middle (Whiterockian) Ordovician age; a similar fauna is reported from the upper Ship Point Formation of Foxe Basin.One new species of the colonial coral Crenulites from the Maysvillian exposures and two new species of conodonts from the subsurface Whiterockian carbonate interbeds are erected.

scholarly journals Notes on some Late Cretaceous goniasterid starfish (Echinodermata, Asteroidea) from Belgium and Germany

2021 ◽  
Vol 73 (3) ◽  
pp. A030321
Author(s):  
John W. M. Jagt ◽  
Elena A. Jagt-Yazykova ◽  
Barry W. M. Van Bakel ◽  
René H. B. Fraaije
Keyword(s):  
New Species ◽  
Late Cretaceous ◽  
Type Species ◽  
Radial Line ◽  
Large Crater ◽  
Two New Species ◽  
Large Spine ◽  
Upper Maastrichtian ◽  
Upper Campanian

Both partially articulated specimens and dissociated marginal ossicles form the basis for erection of two new species of Late Cretaceous goniasterids from the Mons and Liège-Limburg basins (Belgium) and the Hannover area (Germany). Chomataster breizh sp. nov., which recalls the type species, Chomataster acules Spencer, 1913, but differs in several respects, is based on a partial external mould of the marginal frame of disc and arms in flint (upper Campanian Spiennes Chalk Formation; Mons Basin), as well as on a more or less complete individual, preserving small, spherical spines and granules and encased in a flint nodule from the upper Maastrichtian Nekum Member (Maastricht Formation; Liège-Limburg Basin). In Ch. breizh sp. nov., supero- and inferomarginals bear close-set granule pits, of varying sizes, as well as bivalved alveolar scars of pedicellariae; median superomarginals and all inferomarginals lack large, crater-shaped spine pits – such are found only in the disc/arm transition and along the arms. Dissociated supero- and inferomarginal ossicles from the lower and upper Campanian of the Hannover area and the upper Campanian of northeast Belgium, previously recorded either as indeterminate astropectinids or as Nymphaster obtusus (Forbes, 1848) var. nov. and as Nymphaster sp., respectively, here are assigned to Nymphaster mudzborgh sp. nov. This species is characterised by a row of 3–5 large spine pits on the aboral and lateral surfaces of superomarginals; inferomarginals have an angular profile and a close cover of granule pits. Nymphaster tethysiensis Villier, 2001, from the upper Campanian of Landes (southwest France; Villier and Odin, 2001) appears best accommodated in Chomataster as well, because in the arm superomarginals alternate rather than meet over the mid-radial line.

scholarly journals Psoralea diturnerae and P. vanberkelae (Psoraleeae, Fabaceae): two new species restricted to the Core Cape Region of South Africa

PhytoKeys ◽  
2015 ◽  
Vol 44 ◽  
pp. 97-107 ◽  
Author(s):  
Abubakar Bello ◽  
Charles H. Stirton ◽  
Samson M. B. Chimphango ◽  
A. Muthama Muasya
Keyword(s):  
South Africa ◽  
New Species ◽  
The Core ◽  
Two New Species

Khunnuchelys gen.nov., a new trionychid (Testudines: Trionychidae) from the Late Cretaceous of Inner Mongolia and Uzbekistan

1993 ◽  
Vol 30 (10) ◽  
pp. 2214-2223 ◽  
Author(s):  
Donald B. Brinkman ◽  
L. A. Nessov ◽  
Jiang-Hua Peng
Keyword(s):  
New Species ◽  
North America ◽  
Late Cretaceous ◽  
Inner Mongolia ◽  
Monophyletic Clade ◽  
Two New Species ◽  
Faunal Similarity

A new trionychid, Khunnuchelys gen.nov., represented by two new species, Khunnuchelys erinhotensis sp.nov. and Khunnuchelys kizylkumensis sp.nov. is described. Khunnuchelys erinhotensis is based on a large, well-preserved skull from the Iren Dabasu Formation in Inner Mongolia, and K. kizylkumensis is based on a series of partial skulls and isolated skull elements from the Dzhyrakuduk locality, Bissekty Formation, Uzbekistan. The occurrence of this trionychid in these two localities reinforces the suggestion of faunal similarity between the Iren Dabasu and Bissekty formations. Khunnuchelys is distinctive in the extensive development of the triturating surface, proportions of the skull, and features of the braincase. Conchochelys from the Paleocene of North America shares with Khunnuchelys derived features of the palate and braincase, and the two genera may be members of a monophyletic clade of trionychids. Autapomorphies of the triturating surface and associated features in Khunnuchelys are interpreted as durophagous specializations.

Sign in / Sign up

Export Citation Format

Share Document