Campanian and Maastrichtian hippuritid rudists (Hippuritida, Bivalvia) of the Chiapas Central Depression (southern Mexico) and implications for American multiple-fold hippuritid taxonomy

2018 ◽  
Vol 93 (2) ◽  
pp. 291-311
Author(s):  
Jose Maria Pons ◽  
Enric Vicens ◽  
Pedro García-Barrera
Keyword(s):  
Layer Structure ◽  
Outer Shell ◽  
Shell Layer ◽  
Left Valve ◽  
Canal System ◽  
Southern Mexico ◽  
Central Depression ◽  
Pore Canal ◽  
The Caribbean ◽  
The Right

AbstractHippuritids, particularly those with multiple-folds, are one of the most characteristic components in uppermost Cretaceous rudist-bearing strata of the Caribbean Province. The hippuritid rudist fauna of the Chiapas Central Depression includes the following taxa:Vaccinites vermuntiMac Gillavry, 1937 andBarrettiacf.B. ruseaeChubb, 1967 from the early Campanian Suchiapa Formation;B. moniliferaWoodward, 1862,B. gigasChubb, 1955, andParastroma trechmanniChubb, 1967 from the mid Campanian Suchiapa Formation; andPraebarrettia sparcilirata(Whitfield, 1897) from the early Maastrichtian Ocozocoautla Formation. These six species are described herein in detail. New observations on the outer shell layer structure of the right valve and the pore-canal system of the left valve led to amending the diagnoses of the g|eneraBarrettiaWoodward, 1862,ParastromaDouvillé, 1926, andPraebarrettiaTrechmann, 1924. Also, the revision of Chiapas’ and other American species of multiple-fold hippuritids led to proposed changes in their generic adscription.

scholarly journals Paleoecological and paleobiogeographical significance of the rudist Macgillavryia chubbii sp. n. in the Campanian of Oman

GeoArabia ◽  
2003 ◽  
Vol 8 (1) ◽  
pp. 129-146
Author(s):  
Jean M. Philip
Keyword(s):  
New Species ◽  
Sea Water ◽  
Potential Candidate ◽  
Pacific Region ◽  
Left Valve ◽  
The Pacific ◽  
The Caribbean ◽  
The Right ◽  
First Time ◽  
A New Species

ABSTRACT Excellently preserved specimens of the large rudist Macgillavryia have been described for the first time from the Campanian Samhan Formation in the vicinity of Filim and Hayy on the eastern side of the Haushi-Huqf massif in Oman. A new species, M. chubbii, was named and found to be equivalent to other species of Macgillavryia from the Caribbean domain. The exceptionally well-preserved holotype with its articulated valves allowed the reconstruction of the functional morphology of the mantle. The indications are that the left valve of M. chubbii covered only a small part of the commissural area, leaving a large part of the mantle of the right valve directly exposed to sea water and sunlight. As a result, M. chubbii has been proposed as a potential candidate for an association with zooxanthellae. Macgillavryia is a typical epifaunal rudist that probably lived in very shallow, clear seas. The shell was not buried during its lifetime but was exposed to epibionts and bioeroders. The excellent exposures allowed the reconstruction of relationships between Macgillavryia and other biotic or abiotic components. They formed a densely packed association with spaces filled by a very coarse bioclastic material. The superpositioning of two or more layers with superstratal growth fabrics created individual rudist banks more than 1 m thick covering several hundred square meters. Paleobiogeographic reconstructions have connected M. chubbii in Arabia with Macgillavryia in the Caribbean by eastward dispersion through the Pacific region.

Morphology, phylogeny, and systematic revision of genera in the Dimyidae (Mollusca, Bivalvia, Pteriomorphia)

2012 ◽  
Vol 86 (5) ◽  
pp. 829-851 ◽  
Author(s):  
Thomas R. Waller
Keyword(s):  
Late Triassic ◽  
New Combinations ◽  
Shell Layer ◽  
Left Valve ◽  
Systematic Revision ◽  
The Family ◽  
Cryptic Habitats ◽  
Original Habitat ◽  
The Right ◽  
Submarine Caves

Differences in the mineralogy of hinge teeth and inner shell layers in the family Dimyidae form the basis for a revision of genera. The stem genusAtreta(Late Triassic to Late Cretaceous) has aragonitic denticulate hinge teeth on the right valve articulating with pitted sockets on the left valve. The same arrangement is present inNeoatretan. gen. (Paleocene? Miocene to Recent) but with the appearance of extensive calcitic overarching of the resilifer. InDimyella(Eocene to Recent), aragonitic teeth and sockets are still present but are modified into hook shaped denticulate teeth with corresponding sockets. All three of these genera have inner aragonitic crossed-lamellar shell layers that extend well outside the pallial line. In contrast,Dimya(Eocene to Recent) andBasiliomya(Pliocene to Recent) comprise a second clade in which aragonitic hinge teeth are absent and hinge articulation is calcitic, derived from the calcitic rim.Dimyahas only weak hinge articulation and has an aragonitic inner shell layer delimited by the pallial line; inBasiliomyacalcitic hinge teeth are more prominent and the entire inner shell layer inside the pallial line is foliated calcite.Diploschiza(Cretaceous, Albian to Maastrichtian), here reinstated from synonymy withAtreta, is probably a precursor of theDimya-Basiliomyaclade based on incipient calcitic hinge teeth. Predation pressures probably drove the evolution of this cemented family from its original habitat on hardgrounds in moderately deep water into much greater depths or into cryptic habitats, including submarine caves.New combinations areDimyella malnatrensis(Corselli and Bernocchi),D. molokaia(Dall, Bartsch, and Rehder),D. similis(v. Koenen),Neoatreta dissimilis(Tate),N. filipina(Bartsch),N. kaiparaensis(Laws),N. phaidra(Woodring),and N. plana(Martin).

scholarly journals Campanian and Maastrichtian plagioptychid rudists (Hippuritida, Bivalvia) of the Chiapas Central Depression, southern Mexico

2017 ◽  
Vol 91 (2) ◽  
pp. 230-244 ◽  
Author(s):  
Jose Maria Pons ◽  
Enric Vicens ◽  
Pedro García-Barrera
Keyword(s):  
Phylogenetic Analysis ◽  
Minor Component ◽  
Southern Mexico ◽  
Central Depression ◽  
Significant Difference ◽  
The Caribbean ◽  
The Mediterranean ◽  
Lines Of Evidence

AbstractPlagioptychids are a conspicuous, although minor, component in uppermost Cretaceous rudist-bearing outcrops of the Caribbean Province, where other rudist families are more abundant and diverse. In the Chiapas Central Depression, the plagioptychid rudist fauna includes the following taxa: Plagioptychus antillarum (Douvillé) and Mitrocaprina sp. from the middle Campanian Suchiapa Formation, Plagioptychus muellerriedi Alencáster from the early Maastrichtian Ocozocoautla Formation, and Plagioptychus fragilis Chubb and Mitrocaprina tschoppi (Palmer) from the late Maastrichtian Angostura Formation. These five species are described in detail and some probable synonymies are discussed. Analysis of the literature on American plagioptychids reveals that the characters of too many taxa are still insufficiently known to attempt any thorough phylogenetic analysis. Other lines of evidence also seem to indicate that American Plagioptychidae diversity is probably higher than recognized today, which might result in a more significant difference to Plagioptychidae of the Mediterranean Tethys.

scholarly journals National research for health systems in Latin America and the Caribbean: moving towards the right direction?

2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Francisco Becerra-Posada ◽  
Miryam Minayo ◽  
Cristiane Quental ◽  
Sylvia de Haan
Keyword(s):  
Latin America ◽  
Health Systems ◽  
The Caribbean ◽  
The Right

Taxonomy and phylogeny of the Triassic bivalve families Mysidiellidae Cox, 1964 and Healeyidae new family

2008 ◽  
Vol 82 (3) ◽  
pp. 555-564 ◽  
Author(s):  
M. Hautmann
Keyword(s):  
Outer Shell ◽  
Junior Synonym ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Great Similarity ◽  
Shell Layer ◽  
Shell Microstructure ◽  
General Shape ◽  
New Family

The Mysidiellidae are morphologically isolated among Triassic bivalves but share important characters with Late Paleozoic Ambonychioidea. Apart from a great similarity in the general shape of the shell, the most primitive mysidiellid genus Promysidiella resembles ambonychioids in the presence of a duplivincular-opisthodetic ligament system. Within the Mysidiellidae, this ligament type evolved into the transitional ligament system that characterizes Late Triassic Mysidiella. The phyletic polarity indicates that this evolution probably took place by paedomorphosis. New examinations of the shell microstructure of Mysidiella demonstrate the presence of simple prismatic and possibly foliated structures in the calcitic outer shell layer, which further supports an ambonychioid affinity. Therefore, the Mysidiellidae are removed from the Mytiloidea and assigned to the Ambonychioidea. The poorly known genus Protopis, which was originally included in the Mysidiellidae, probably had a parivincular ligament system and was hence a member of the Heteroconchia. Joannina, which was previously considered a junior synonym of Protopis, is re-established. The hinge margin of Joannina carries a well developed nymph but lacks teeth. These characters as well as its modioliform shape, anterior shell lobe, and pronounced diagonal carina link Joannina with the Late Triassic genus Healeya (Modiomorphoidea). Both taxa are herein placed in the new family Healeyidae, which differs from the morphologically similar Kalenteridae in the absence of elaborated hinge teeth. Protopis, as well as the recently described genera Leidapoconcha, Waijiaoella, and Qingyaniola, are tentatively assigned to the Healeyidae.

Geographical review of the ostracod genus Vestalenula (Darwinulidae) and a new subterranean species from southern France

2007 ◽  
Vol 21 (5) ◽  
pp. 471 ◽  
Author(s):  
Malvina Artheau
Keyword(s):  
New Record ◽  
Cladistic Analysis ◽  
Left Valve ◽  
Southern France ◽  
Recent Species ◽  
European Program ◽  
The Right ◽  
Subterranean Species ◽  
A New Species ◽  
Subterranean Environment

A new species of Vestalenula is described. Vestalenula carveli, sp. nov. was found in the interstitial habitat of rivers during the PASCALIS European program when sampling three sites on the Aude River and Tech River basins (Roussillon region, southern France). With its large caudal brooding cavity, the presence of an external keel on the right valve and an internal tooth on the left valve, V. carveli is a typical representative of the genus. This new record brings the worldwide number of Vestalenula species to 24. Vestalenula representatives are known from the Lower Miocene to the present. A review of present-day knowledge of the geographical distribution of the genus and a cladistic analysis are presented in order to assess the biogeography of this genus and the importance of the discovery of a new subterranean species in southern France. The geographical review of the genus showed that most species of Vestalenula occur in subtropical regions. However, V. cylindrica, V. boteai and V. danielopoli lived, or are living, in the Palearctic. Vestalenula pagliolii occurs in both hemispheres. Many of the Recent species live in semiterrestrial and/or interstitial habitats and occur in geographically restricted areas. The distribution of the species of Vestalenula suggests independent colonisation of the subterranean environment by several species; this hypothesis is supported by the cladistic analysis.

scholarly journals The Generative Organs of the Oyster

1890 ◽  
Vol 1 (3) ◽  
pp. 268-281 ◽  
Author(s):  
Gilbert C. Bourne
Keyword(s):  
Adductor Muscle ◽  
Reproductive Organs ◽  
Posterior Surface ◽  
Anterior Surface ◽  
Left Valve ◽  
Left Hand ◽  
Natural Position ◽  
The Right ◽  
Ventral Border ◽  
Generative Organs

The following description of the reproductive organs of the oyster cannot well be understood without some acquaintance with the general anatomy of the animal. With the help of Pl. XXII, fig. 1, the most important features of its anatomy may readily be understood. It must be remembered that the valves of the oyster's shell lie right and left of the animal; that the concave valve which lies undermost in the natural position of the animal is the left valve, and the flat upper valve is the right valve. The hinge marks the dorsal border of the animal, and the opposite border is the ventral border. That side which is on the observer's right in fig. 1 is the anterior surface, and that on the left hand is the posterior surface. As the animal is compressed from side to side the anterior and posterior surfaces are very narrow. The great adductor muscle, by which the valves of the shell are closed, is seen lying in the centre of the animal in fig. 1.

Introduction

2018 ◽  
Author(s):  
Mia L. Bagneris
Keyword(s):  
Caribbean Sea ◽  
British Art ◽  
Palm Trees ◽  
Natural Beauty ◽  
The Caribbean ◽  
The Right

July 2007, Yale Center for British Art – reflections on Agostino Brunias’s A Planter and his Wife (fig. 1) … The painting is relatively small – about 12 x 10 inches – and a wonderfully exquisite little gem, its bright gold frame setting off the work of a talented colourist. Pristine whites and vivid pale blues are punctuated with punches of coral red; deep greens and rich ochres define the landscape. In the background are all the hallmarks of an idyllic island day; under a perfect canopy of blue sky and fluffy white clouds, a pair of palm trees rise in the right margin of the picture, nestled against the calm, crystal waters of the Caribbean Sea. However, in the midst of this quintessential tropical splendour, two figures in the foreground, a man and a woman, command the viewer’s immediate attention. Although he is dressed to beat the heat, the man manages to cut an impressive figure in long white trousers, white shirt, and white waistcoat – all immaculately spotless. He accessorises the outfit with black cravat, black shoes with silver buckles, and a long mustard-coloured dress coat with shiny gold buttons, completing the ensemble with a black ‘planter’s hat’. Surely his elegant dress demonstrates his wealth and status, but not so much as his pose, for the artist has frozen him in a perpetual state of showing off; his outstretched arm gestures towards the splendid natural beauty all around him as he turns his face to the lady at his side in a move that silently proclaims his ownership of all that surrounds them....

From Christian to Jew

2021 ◽  
pp. 27-45
Author(s):  
Laura Arnold Leibman
Keyword(s):  
Jewish Community ◽  
Caribbean Sea ◽  
People Of Color ◽  
South American ◽  
Crucial Step ◽  
The Caribbean ◽  
American Colony ◽  
The Right

The next crucial step in the siblings’ journey to gain the right to live and pray as they pleased came in 1811 when they moved to Suriname, a South American colony on the Caribbean Sea. In Suriname, Sarah and Isaac found their home among the largest multiracial Jewish community in the Americas and formally converted to Judaism. This community provided a spiritual home for Sarah and Isaac, but it also marked them as second-class citizens. Since their father, Abraham, had not married their mother, Surinamese law considered Sarah and Isaac people of color. This racial designation followed them into the synagogue, where they would sit separately from whites and couldn’t partake in synagogue honors. This chapter places the siblings’ experiences alongside that of other multiracial Jews who lived in Paramaribo at that time, highlighting their battles against oppression.

Soil Particle Surface Charge

2016 ◽  
Author(s):  
Garrison Sposito
Keyword(s):  
Layer Structure ◽  
Particle Surface ◽  
Electronic Charge ◽  
Isomorphic Substitution ◽  
Hexagonal Symmetry ◽  
Cleavage Surface ◽  
Octahedral Sheet ◽  
Weak Hydrogen Bonds ◽  
Lower Valence ◽  
The Right

Structural charge arises on the surfaces of soil mineral particles in which either cation vacancies or isomorphic substitutions of cations by cations of lower valence occur. The principal minerals bearing structural charge are therefore the micas (Section 2.2), the 2:1 clay minerals (Section 2.3), or the Mn(IV) oxide, birnessite (Section 2.4). These three classes of mineral are all layer type and the cleavage surface on which their structural charge is manifest is a plane of O ions. The plane of O ions on the cleavage surface of a layer-type aluminosilicate is called a siloxane surface.This plane is characterized by hexagonal symmetry in the configuration of its constituent O ions, as shown at the top of Fig. 2.3 and, more explicitly, on the right side of Fig. 2.4, where a portion of the siloxane surface of the micas is depicted. Reactive molecular units on the surfaces of soil particles are termed surface functional groups. The functional group associated with the siloxane surface is the roughly hexagonal (strictly speaking, ditrigonalbecause the hexagonal symmetry is distorted when the tetrahedral sheet is fused to an octahedral sheet to form a layer) cavity formed by six corner-sharing silica tetrahedra. This cavity has a diameter of about 0.26 nm. The reactivity of the siloxane cavity depends on the nature of the electronic charge distribution in the layer structure. If there are no nearby isomorphic cations substitutions to create a negative charge, the O ions bordering the siloxane cavity function as an electron cloud donor that can bind molecules weakly through the van der Waals interaction. These interactions are akin to those underlying the hydrophobic interaction, discussed in Section 3.5, because the O in the siloxane surface can form only very weak hydrogen bonds with water molecules. Therefore, uncharged patches on siloxane surfaces may be considered hydrophobic regions to a certain degree, with, accordingly, an attraction for hydrophobic organic molecules. However, if isomorphic substitution of Al3+ by either Fe2+ or Mg2+ occurs in the octahedral sheet, the resulting structural charge is manifest on the siloxane cavities, as discussed in Section 2.3.

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