CHONDRICHTHYANS FROM THE ARKADELPHIA FORMATION (UPPER CRETACEOUS: UPPER MAASTRICHTIAN) OF HOT SPRING COUNTY, ARKANSAS

2006 ◽  
Vol 80 (4) ◽  
pp. 700-716 ◽  
Author(s):  
MARTIN A. BECKER ◽  
JOHN A. CHAMBERLAIN ◽  
GEORGE E. WOLF
2018 ◽  
Vol 93 (2) ◽  
pp. 278-290
Author(s):  
J. Mark Erickson

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


2020 ◽  
pp. 57-67
Author(s):  
Felix Schlagintweit ◽  
Koorosh Rashidi

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.


2003 ◽  
Vol 72 (2-3) ◽  
pp. 135-136
Author(s):  
Alessandro Garassino ◽  
Giovanni Pasini

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.


1994 ◽  
Vol 68 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Kasana Pitakpaivan ◽  
Joseph E. Hazel

The ostracode assemblage of the Arkadelphia Formation, upper Maastrichtian, of southwestern Arkansas is characterized by a well-preserved, relatively diverse, and abundant fauna representing 36 podocopid species and an undetermined number of species of the platycopid genus Cytherella. Thirteen of these account for 85 percent of the fauna. The dominant forms are Cytherella spp., Brachycythere rhomboidalis (Berry, 1925), Haplocytheridea renfroensis Crane, 1965, Haplocytheridea bruceclarki (Israelsky, 1929), and Brachycythere ovata (Berry, 1925), which account for about 57 percent of the specimens found. Other species that are less common, but are characteristic of the Arkadelphia, are Antibythocypris macropora (Alexander, 1929), Ascetoleberis hazardi (Israelsky, 1929), Aversovalva fossata (Skinner, 1956), Brachycythere ledaforma (Israelsky, 1929), Curfsina communis (Israelsky, 1929), Cytheromorpha arbenzi (Skinner, 1956), Escharacytheridea micropunctata (Alexander, 1929), and Veenia arachoides (Berry, 1925). The ostracode assemblage indicates that the Arkadelphia was deposited in the inner sublittoral zone.The species Veenia parallelopora (Alexander, 1929) and Brachycythere foraminosa Alexander, 1934, are restricted to the Arkadelphia Formation and allow correlation with other Gulf Coastal Plain Upper Cretaceous units. A new ostracode interval zone, the Veenia parallelopora Zone, is proposed. This zone divides the Platycosta lixula Zone.Calcareous planktic microfossils reported from the Arkadelphia and its correlatives in the Veenia parallelopora Zone indicate that these deposits are late Maastrichtian in age, not middle Maastrichtian as some authors have thought.


2019 ◽  
Vol 48 (1) ◽  
pp. 73-101
Author(s):  
Georgi Granchovski

A detailed investigation into the calcareous nannofossils from the upper Campanian–Maastrichtian deposits of the Kladorub Formation (NW Bulgaria) has been carried out in order to examine their taxonomic content and test the applicability of cosmopolitan zonation schemes for this stratigraphic interval in the country. The Kladorub Formation is composed of silty to fine-sandy marlstones and rare marly limestones, occasionally interbedded with sandstone layers. The recovered nannofloras are abundant, taxonomically diverse and exhibit predominantly moderate preservation, which allowed precise taxonomic identifications and biostratigraphic analysis to be made. As a result, the presence of two previously undocumented, biostratigraphically significant taxa has been recorded (i.e., Eiffellithus parallelus and Ceratolithoides kamptneri). Consequently, the studied Upper Cretaceous sediments have been assigned to subzone UC15dTP (pars.)–subzone UC20dTP; in the uppermost 2 m of the section, the presence of zone NP1 has also been indicated, which is in concordance with previous authors’ data. Due to the lack of proper chronostratigraphic framework for the Kladorub Formation, top Uniplanarius trifidus and base Lithraphidites quadratus have, respectively, been used to approximate the Campanian/Maastrichtian and lower/upper Maastrichtian boundaries. The Cretaceous/Palaeogene boundary, however, could not be drawn with precision, because it falls within a 6.5-m interval of non-exposure. The resulting biostratigraphic framework offers higher stratigraphic resolution than previously used local zonation schemes and allows correlation with coeval sedimentary successions from other parts of the Tethyan and Boreal realms.


2000 ◽  
Vol 74 (2) ◽  
pp. 224-229 ◽  
Author(s):  
Dale Tshudy ◽  
Ulf Sorhannus

A new genus and species of clawed lobster, Jagtia kunradensis, is described from the Upper Cretaceous (Upper Maastrichtian) Kunrade Limestone facies of the Maastricht Formation, The Netherlands. Three nephropid lobster genera and at least three species (Oncopareia bredai Bosquet, 1854, sensu Tshudy, 1993, Oncopareia sp. Tshudy, 1993, Hoploparia beyrichi Schlüter, 1862, and Jagtia kunradensis) have now been collected from limestones of the Maastrichtian type area (southeastern Netherlands and northeastern Belgium). Cladistic methods were employed in re-evaluating the phylogenetic relationships of the nephropid lobsters, including Jagtia. These analyses indicate that Jagtia is part of a clade that includes the recent Thymops and Thymopsis. The new genus is the first fossil form to be closely allied with these deep-water genera.


2005 ◽  
Vol 84 (3) ◽  
pp. 167-175 ◽  
Author(s):  
N. Bardet ◽  
X. Pereda Suberbiola ◽  
M. Iarochène ◽  
M. Amalik ◽  
B. Bouya

AbstractThree durophagous mosasaur species are represented by isolated teeth in the Upper Cretaceous (Maastrichtian) phosphatic beds of Morocco. Globidens phosphaticus nov. sp. is characterised mainly by a strong heterodonty, with mid-posterior teeth being bulbous, irregularly oval in crosssection, and having an inflated posterior surface, a large eccentric located and recurved apical nubbin, vertical sulci on medial and lateral faces, no carinae and an enamel surface covered by anastomosing ridges. Teeth of Prognathodon currii are broad and tall, straight cones, slightly swollen at the base, and with two serrated carinae. These two taxa have been collected from all the phosphatic series (lower to upper Maastrichtian) in the Ganntour Basin (Morocco). Globidens phosphaticus nov. sp. is probably also represented at other Maastrichtian phosphatic sites along the southern margin of the Mediterranean Tethys. Prognathodon currii was previously known only from the Upper Cretaceous phosphates of Negev. Of the third taxon, Carinodens belgicus, only a single tooth (now lost) is known from the Oulad Abdoun Basin (Morocco); this is low, swollen, laterally compressed and bicarinate with a large apical nubbin. Previous records of this species include Europe and Brazil.


1987 ◽  
Vol 61 (1) ◽  
pp. 101-111 ◽  
Author(s):  
Victor A. Zullo ◽  
Ernest E. Russell ◽  
Frederic F. Mellen

Brachylepas americana n. sp. is described from abundant and well-preserved capitular and basal whorl plates from a littoral facies in the basal part of an Upper Cretaceous (upper Campanian) conglomerate questionably assigned to the Brownstown Formation in Hot Spring County, Arkansas. The new species resembles the European littoral Campanian–Maastrichtian species B. guascoi (Bosquet), and differs markedly from the only other known American species, B. angulosa Collins, from the Upper Cretaceous middle Ripley Formation of Mississippi. A few juvenile carinae of Virgiscalpellum may represent V. gabbi apertus Collins, previously known from the Ripley and basal Prairie Bluff Formations in Mississippi.


2001 ◽  
Vol 34 (1) ◽  
pp. 111 ◽  
Author(s):  
A. PHOTIADES ◽  
F. ΡΟΜΟΝΙ-ΡΑΡΑΙΟΑΝΝΟΥ

The Rhodiani area geologically is comprised of a sequence of Mesozoic and Tertiary thrust sheets, including the Jurassic ophiolite and sedimentary covers; they composed of an ultramafic unit overlain by an Albian to Cenomanian redeposited limestone cover, and at the top a volcanic unit that is overlain by neritic to pelagic Upper Jurassic to Upper Cretaceous age limestone and Upper Maastrichtian flysch deposits. These thrust sheets were emplaced over the Pelagonian platform. Therefore the Rhodiani "ophiolite" is not a single thrust unit, but it is an imbricated ophiolite tectonic structure resulting from a two-stage emplacement process; the ultramafic unit was overthrust on the melange of the Pelagonian platform during the initial emplacement (Jurassic) and the volcanic unit was re-thrust on the former during subsequent post-Eocene tectonic phase


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