scholarly journals Cretaceous cultch: substrate availability for oyster Exogyra in the Maastrichtian of the eastern Mississippi Embayment

2020 ◽  
Vol 37 (3) ◽  
pp. 197-211
Author(s):  
Marvin Kunath ◽  
George Phillips ◽  
Renee M. Clary
Keyword(s):  
Upper Cretaceous ◽  
Southeastern United States ◽  
Taxonomic Diversity ◽  
Skeletal Remains ◽  
Substrate Availability ◽  
Mississippi Embayment ◽  
Shallow Marine ◽  
Northeast Mississippi ◽  
Upper Maastrichtian ◽  
Benthic Population

The gryphaeid oyster Exogyra Say, 1820, is ubiquitous in Upper Cretaceous sediments in the southeastern United States. Like many oysters (Order Ostreida), Exogyra attached its shell to hard surfaces on the seafloor by means of cementation. Throughout its lifetime, Exogyra may preserve through bioimmuration the characteristics and even skeletal remains of substrate organisms, including mollusk shells, echinoids, and bryozoans. Exogyra costata of all sizes were collected from three different localities within upper Maastrichtian deposits in northeast Mississippi and their bioimmurations analyzed. Substrates were identified and classified to compare the three localities’ substrate taxa in order to probe differences in benthic population structure. The results of this pilot study provide an overview of available surfaces on the Late Cretaceous seafloor on the eastern side of the Mississippi Embayment. The data suggest that taxonomic diversity among utilized substrates may increase from north to south, which corresponds to increasing depth from shallow marine to deeper sediments on the shelf.

Neritoptyx hogansoninew species (Gastropoda, Mollusca) from the Upper Cretaceous Fox Hills Formation on the Dakota Isthmus, western United States

2018 ◽  
Vol 93 (2) ◽  
pp. 278-290
Author(s):  
J. Mark Erickson
Keyword(s):  
Heat Transfer ◽  
United States ◽  
New Species ◽  
North America ◽  
Upper Cretaceous ◽  
Gulf Coast ◽  
Western United States ◽  
Western Interior Seaway ◽  
Decapod Crustaceans ◽  
Upper Maastrichtian

AbstractIn midcontinent North America, the Fox Hills Formation (Upper Cretaceous, upper Maastrichtian) preserves the last marine faunas in the central Western Interior Seaway (WIS).Neritoptyx hogansoninew species, a small littoral snail, exhibited allometric change from smooth to corded ornament and rounded to shouldered shape during growth. Specimens preserve a zig-zag pigment pattern that changes to an axial pattern during growth.Neritoptyx hogansoninew species was preyed on by decapod crustaceans, and spent shells were occupied by pagurid crabs. Dead mollusk shells, particularly those ofCrassostrea subtrigonalis(Evans and Shumard, 1857), provided a hard substrate to which they adhered on the Fox Hills tidal flats. This new neritimorph gastropod establishes a paleogeographic and chronostratigraphic proxy for intertidal conditions on the Dakota Isthmus during the late Maastrichtian. Presence of a neritid extends the marine tropical/temperate boundary in the WIS northward to ~44° late Maastrichtian paleolatitude. Late Maastrichtian closure of the isthmus subsequently altered marine heat transfer by interrupting northward flow of tropical currents from the Gulf Coast by as much as 1 to 1.5 million years before the Cretaceous ended.UUID:http://zoobank.org/3ba56c07-fcca-4925-a2f0-df663fc3a06b

scholarly journals BROECKINELLA HENSONI N. SP., A NEW LARGER BENTHIC FORAMINIFERA FROM THE UPPER MAASTRICHTIAN OF IRAN AND A REVISION OF THE GENUS BROECKINELLA HENSON, 1948

2020 ◽  
pp. 57-67
Author(s):  
Felix Schlagintweit ◽  
Koorosh Rashidi
Keyword(s):  
Benthic Foraminifera ◽  
Upper Cretaceous ◽  
Test Chamber ◽  
First Record ◽  
Generic Diagnosis ◽  
Larger Benthic Foraminifera ◽  
Zagros Zone ◽  
Sw Iran ◽  
Tarbur Formation ◽  
Upper Maastrichtian

new larger benthic foraminifera is described as Broeckinella hensoni from the upper Maastrichtian Tar-bur Formation of SW Iran (Zagros Zone). In comparison to the type species of the genus, Broeckinella arabica Henson, which also occurs in the Tarbur Formation, the new species has distinctly larger dimensions (e.g., size and thickness of test, chamber height). The first record of a microspheric specimen of B. arabica shows previously unrecorded annular chambers in the final test stage. Therefore, the generic diagnosis is herein emended. In the Tarbur Formation, both B. hensoni n. sp. and B. arabica occur in foraminiferal-algal wackestones. However, B. arabica occurs in a wider range of microfacies, including packstones and grainstones. It is assumed that Broeckinella originated in the Upper Cretaceous with Broeckinella neumannae Gendrot. The upper Albian Broeckinella aragonensis Peybernès is herein transferred to the porcellaneous genus Peneroplis Montfort.

scholarly journals First record of Calappoidea and Dromioidea from the Upper Cretaceous (Upper Maastrichtian) of NW Madagascar

2003 ◽  
Vol 72 (2-3) ◽  
pp. 135-136
Author(s):  
Alessandro Garassino ◽  
Giovanni Pasini
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
First Record ◽  
Upper Maastrichtian

The crustaceans from the marine Berivotra Formation, dated as late Cretaceous, from 50 km south of Mahajanga, Madagascar contains macrurans, brachyurans and thalassinideans. Two brachyuran families, Raninidae and Dynomenidae, were previously identified with the genera Notopocorystes, Caloxanthus, Titanocarcinus, Xanthosia, and Dromiopsis. Fragmentary material now also allows the recognition of Dromioidea, Calappoidea and Xanthoidea.

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