Lower and middle Cambrian rhynchonelliform brachiopods from the Precordillera terrane of Argentina

2012 ◽  
Vol 86 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Juan L. Benedetto ◽  
Rodolfo D. Foglia
Keyword(s):  
Cluster Analysis ◽  
New Species ◽  
Warm Water ◽  
Carbonate Platforms ◽  
Middle Cambrian ◽  
Central Argentina ◽  
Mountain Belt ◽  
West Central ◽  
Lowermost Part

The first Cambrian rhynchonelliformean brachiopods are described from the Precordillera mountain belt of west-central Argentina, including the new species Wimanella mollensis and Nisusia ancauchensis. Other forms are Diraphora cf. D. borealis (Walcott), Diraphora sp., and an indeterminate bohemiellid. Brachiopods come from the lowermost part of the Precordilleran Cambrian succession (El Estero and Soldano Members of the La Laja Formation, Cerro Totora Formation) and from the Ancaucha olistolith within the Los Sombreros olistostrome. The associated trilobites constrain the fossiliferous levels to the Bonnia-Olenellus, Poliella denticulata and Ehmaniella biozones. A re-assessment of paleobiogeographic affinities of lower and early middle Cambrian rhynchonelliform brachiopods using cluster analysis supports the existence of a widespread warm-water Tropical Realm—to which the described Precordilleran faunas belong—and a more restricted ‘Mediterranean’ Realm developed on the temperate, mixed clastic-carbonate platforms.

First articulated stalked crinoids from the Mesozoic of South America: two new species from the Lower Cretaceous of the Neuquén Basin, west-central Argentina

2020 ◽  
Vol 94 (4) ◽  
pp. 716-733
Author(s):  
Darío G. Lazo ◽  
Graciela S. Bressan ◽  
Ernesto Schwarz ◽  
Gonzalo D. Veiga
Keyword(s):  
New Species ◽  
Lower Cretaceous ◽  
Carbonate Sediments ◽  
Exceptional Preservation ◽  
Central Argentina ◽  
West Central ◽  
Subaqueous Dunes ◽  
Neuquen Basin ◽  
Neuquén Basin ◽  
Slender Column

AbstractTwo new isocrinids are described from the Lower Cretaceous Agrio Formation of the Neuquén Basin, west-central Argentina. Isocrinus (Chladocrinus) covuncoensis new species is based on several beautifully preserved specimens from Valanginian beds of the Pilmatué Member. It is characterized by a small size, multiramose crown with six arm divisions, 240 arm tips, mostly isotomous branching, seven (or rarely eight) secundibrachials, smooth and stout column, short noditaxis, and pentalobate columnals. The species occurs in a 30 m thick interval of cross-bedded sandstones and mixed clastic-carbonate sediments that represent the migration of large, tidally influenced, subaqueous dunes developed in the offshore. Sudden burial of crinoids that dwelled on the dune toes and interdunes, possibly by the acceleration of the lee face migration, provided the exceptional preservation of specimens and thus this finding can be considered as a local crinoid Konservat Lagerstätte. Isocrinus (Chladocrinus) pehuenchensis new species is described from a single articulated specimen preserved in a silty calcareous concretion collected from a late Hauterivian concretion level of the Agua de la Mula Member. It is characterized by isotomous branching, eight or nine secundibrachials (IIBr), slender column ornamented with medial ridge of fine tubercles, interradius acuminated with fine tubercles on its tip, short noditaxis, and pentastellate columnals. It is associated with low-energy fall-out deposits in the offshore. The excellent state of preservation was due to an early cementation process by carbonate that enhanced lithification around the specimen.UUID: http://zoobank.org/4763ae70-9d0a-4015-b1c9-6a7ceeedfb1a

The gastropod family Aporrhaidae in the Lower Cretaceous of the Neuquén Basin, west-central Argentina

2014 ◽  
Vol 88 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Cecilia S. Cataldo
Keyword(s):  
New Species ◽  
Lower Cretaceous ◽  
Single Species ◽  
Central Argentina ◽  
West Central ◽  
Neuquen Basin ◽  
Moderate Energy ◽  
Neuquén Basin ◽  
Water Carbonate

The gastropod fauna of the Lower Cretaceous of the Argentinian Neuquén Basin contains three aporrhaid species.Protohemichenopus neuquensisCamacho, 1953 is the most abundant, longest-lived, and most geographically widespread of the aporrhaids of this basin, and its protoconch and early teleoconch whorls were unknown until now. The new speciesDimorphosoma weaverifeatures convex to subtly angular spire whorls with opisthocyrt collabral ribs that are more prominent towards the mid-whorl, a bicarinate last whorl with small rounded nodes on the adapical carina, a simple, falcate labral wing which is more or less rectangular proximally and tapering and curving towards its distal end, and a short, straight rostrum.Tylostoma jaworskiiWeaver, 1931 is now placed inHarpagodes, and other previous, scattered, coeval records of this genus in the basin are now recognized as part of this single species. It is believed that whereasH. jaworskiipreferred shallower-water carbonate settings of low to moderate energy,P. neuquensisandD. weaverifavored siliciclastic to mixed clastic-carbonate environments, in deeper waters. In spite of its endemic elements, this aporrhaid association depicts a predominantly Tethyan influence.

scholarly journals Further contributions to the knowledge of the Palaeozoic of Slagelse no. 1, Western Sealand

1974 ◽  
Vol 101 ◽  
pp. 1-42
Author(s):  
Chr. Poulsen
Keyword(s):  
New Species ◽  
Lower Cambrian ◽  
Upper Permian ◽  
Deep Borehole ◽  
Middle Cambrian ◽  
Lower Silurian ◽  
Alum Shale ◽  
Framboidal Pyrite ◽  
Lowermost Part ◽  
A New Species

The material described and discussed in the present paper originates from a deep borehole near Slagelse on western Sealand. The lowermost strata have been referred to the Lower Cambrian (Sorgenfrei & Buch 1964 and C. Poulsen 1969). The present paper deals with the succession of strata between the Lower Cambrian and the Upper Permian evaporite series. The sediments in question are: Alum shale (lowermost part possibly Middle Cambrian and uppermost part possibly basal Ordovician), shales and siltstones with Lower Silurian graptolites (Table 2, p. 11), red, silty claystone (Rotliegendes?), and finally grey dolomite and dark grey, thinly laminated shale with Upper Permian gymnosperm pollen and numerous remains of a vigorous vegetation of hepatics.The description and discussion of the Silurian fossils embrace trace fossils, brachiopods, eurypterids, asteroids, graptolites (e.g. two new species of Dictyonema and a new species of Monograptus), and finally a few vertebrate scales. A study of numerous Silurian specimens of framboidal pyrite resulted in several new observations; the framboids may be explained as primitive pyritized algae.The Upper Permian microflora contains a very predominant new species of Lueckisporites; the macroflora consists exclusively of new species of hepatics referable to Jungermannites and Gessella n.g.The Palaeozoic palaeogeography and geological development of the Slagelse region is discussed in connection with a comparison with sections of some other localities.

scholarly journals Enlarging rodent diversity in west-central Argentina: a new species of the genusHolochilus(Cricetidae, Sigmodontinae)

2013 ◽  
Vol 94 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Ulyses F. J. Pardiñas ◽  
Pablo Teta ◽  
Damián Voglino ◽  
Fernando J. Fernández
Keyword(s):  
New Species ◽  
Central Argentina ◽  
West Central ◽  
A New Species

Cenozoic tectonics of the High Andes of west-central Argentina (30–36°S latitude)

1996 ◽  
Vol 259 (1-3) ◽  
pp. 185-200 ◽  
Author(s):  
Victor A. Ramos ◽  
Marcelo Cegarra ◽  
Ernesto Cristallini
Keyword(s):  
Central Argentina ◽  
West Central ◽  
Cenozoic Tectonics

A New Species of Cupressinocladus from the Lower Cretaceous of Guyang Basin, Inner Mongolia, China and Cluster Analysis

2017 ◽  
Vol 91 (4) ◽  
pp. 1200-1214 ◽  
Author(s):  
Peihong JIN ◽  
Teng MAO ◽  
Junling DONG ◽  
Zixi WANG ◽  
Mingxuan SUN ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
New Species ◽  
Lower Cretaceous ◽  
Inner Mongolia ◽  
And Cluster Analysis ◽  
A New Species

New well-preserved scleritomes of Chancelloriida from early Cambrian Guanshan Biota, eastern Yunnan, China

2018 ◽  
Vol 92 (6) ◽  
pp. 955-971 ◽  
Author(s):  
Jun Zhao ◽  
Guo-Biao Li ◽  
Paul A. Selden
Keyword(s):  
New Species ◽  
Detailed Comparison ◽  
The Body ◽  
Single Element ◽  
Early Cambrian ◽  
Top Down ◽  
Middle Cambrian ◽  
Unusual Form ◽  
Guanshan Biota ◽  
A New Species

AbstractA large number of well-preserved chancelloriid scleritomes from the Guanshan biota, early Cambrian of Yunnan, China, are described as a new species,Allonnia tenuisn. sp., and provide solid evidence for the original appearance of these enigmatic animals, based on specimens compacted laterally and top-down. With the assistance of a flexible integument, chancelloriids, especiallyAllonniafrom early and middle Cambrian, may have had the ability to partially or completely expand and contract the body, which might have played an important role in feeding. A new metazoan with single-element spines,Nidelric gaoloufangensisn. sp., is also described. Preservation and affinity are discussed. Detailed comparison of the morphology of the body and spines of this metazoan indicate that it shares many similarities with chancelloriids, of which it may be an unusual form.UUID:http://zoobank.org/2708d95a-1fae-46fc-afea-9707ae97a4d7

Kochiella Poulsen, 1927, and Hadrocephalites new genus (Trilobita: Ptychopariida) from the early Middle Cambrian of western North America

2002 ◽  
Vol 76 (1) ◽  
pp. 76-94 ◽  
Author(s):  
Frederick A. Sundberg ◽  
Linda B. McCollum
Keyword(s):  
New Species ◽  
North America ◽  
New Genus ◽  
Western North America ◽  
Type Specimens ◽  
Middle Cambrian ◽  
Informal Group ◽  
Nomen Dubium

Kochaspids are an informal group of ptychopariid trilobites that were both abundant and widespread in the early Middle Cambrian of North America. Based on the reassociation of pygidia and cranidia of some kochaspids, Kochiella Poulsen, 1927, is redefined and Hadrocephalites n. gen. is proposed. Hadrocephalites includes taxa previously assigned by Rasetti and Palmer to Schistometopus Resser, 1938a. Schistometopus is considered nomen dubium. Representatives of Kochiella and Hadrocephalites from the Pioche Shale and Carrara Formation of Nevada are described, including the new species Kochiella rasettii, K. brevaspis, Hadrocephalites lyndonensis, and H. rhytidodes. Other kochaspids previously assigned to Kochaspis Resser, 1935; Eiffelaspis Chang, 1963; Schistometopus; and Kochiella are discussed and some are reassigned. The type specimens of Kochiella augusta (Walcott, 1886); K. crito (Walcott, 1917b); K. chares (Walcott, 1917a); K. mansfieldi Resser, 1939; K. arenosa Resser, 1939; Hadrocephalites carina (Walcott, 1917b), and H. cecinna (Walcott, 1917b) are re-illustrated.

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