The eoorthid brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the dispersal pathways along western Gondwana

The eoorthid brachiopod Apheoorthina is reported for the first time from the Lower Ordovician of NW Argentina. It is represented by a species similar to A. ferrigena from the Tremadocian of the Prague Basin, increasing the faunal affinities between the Central Andean Basin and the South European microcontinents, in particular the Bohemian region (Perunica). Nine out of the fourteen brachiopod genera reported from the Tremadocian of the Central Andean Basin (~64 %) are shared with the Mediterranean region, four of which (~ 28 %) have been recorded in the Prague Basin, and two (Kvania and Apheoorthina) are restricted to the Central Andes and Perunica. Dispersal pathways around Gondwana are analyzed in the light of major factors affecting large-scale distribution of brachiopods (environment, larval capacity for dispersal, oceanic currents).The presence in Apheoorthina aff. ferrigena of a well-preserved larval protegulum measuring 420 μm in width and 210 μm in length strongly suggests that this species had planktotrophic larvae capable of long-distance dispersal. According to recent oceanatmosphere general circulation models for the Ordovician Period, the Central Andean margin was dominated by the cold-water Antarctica Current. Despite the complex nonzonal pattern produced by current deflections around the peri-Gondwanan microcontinents, the general westward circulation sense favoured larval dispersal from the Andean region to North Africa, Avalonia, the Armorican Terrane Assemblage, and Perunica. On the other hand, the eastwards flowing Gondwana Current connected the North Gondwana waters with the South American epicontinental seas, which could explain the reversed migration of some brachiopods.Fil: Muñoz, Diego Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Linguloidean brachiopods from the Lower Ordovician (Tremadocian) of northwestern Argentina

The new obolid Torobolus subplanus gen. et sp. nov., from the lower Temadocian Devendeus Formation, the new species Libecoviella tilcarensis and Leptembolon argentinum, and Ectenoglossa sp. from upper Tremadocian beds of the Santa Rosita Formation are described and ilustrated. Libecoviella is typical of the upper Tremadocian and Floian strata of the Prague basin (Trenice and Klabava formations, respectively) and it has been reported recently from Australia. Leptembolon has been recorded in the same Bohemian formations, but together with other taxa it forms the Thysanotos-Leptembolon Association present in northern Estonia and a series of high-latitude terranes. The record of Leptembolon and Libecoviella in the high- to temperate-latitude Central Andean region attests for a peri-Gondwanan distribution of these genera. The presence of Bohemian-like obolids in northwestern Argentina suggests a migratory route linking the Central Andean basin with north Gondwana and Perunica along the clastic platforms fringing the North African and Brazilian shieldsFil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Muñoz, Diego Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Reassessment of the spinose polytoechiid brachiopod pinatotoechia Benedetto from the Lower Ordovician of western Argentina

PINATOECHIA (type species Pinatotoechia acantha Benedetto) is a peculiar spinose polytoechiid hitherto confined to the Famatina-Puna volcanic-arc system fringing the Andean margin of Gondwana during the Ordovician. This genus was described originally from the volcanosedimentary Aguada de la Perdiz Formation exposed west of Salar del Rincón in the Puna region of NW Argentina, a few kilometers from the international border with Chile. According to the associated trilobites as well as the graptolites from correlatable units, the age of these beds is latest Floian-early Dapingian. New and better preserved specimens of Pinatotoechia acantha were subsequently collected from the nearly coeval volcaniclastic Suri Formation of the Famatina Range (Benedetto, 2003). Rubel (2007), in the supplement of the revised Treatise, put in synonymy Pinatotoechia Benedetto with Tritoechia Ulrich and Cooper arguing that the spines of the former are, in fact, identical to the aditicules of the type species Tritoechia typica (Schuchert and Cooper, 1932). The purpose of this paper is to present conclusive evidence on the presence of true hollow spines erected on the tops of costellae in order to support the validity of the genus and to improve its description and illustration. Likewise, the ventral interior of Pinatotoechia is redescribed and reillustrated to show that its pseudospondylium and ventral muscle pattern clearly differ from those of Tritoechia.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Phylogenetic relationships of the Silurian Afro-South American brachiopods Anabaia, Harringtonina and Clarkeia: New insights from their ontogeny

Hundreds of specimens of the rhynchonellide brachiopod Clarkeia antisiensis (d’Orbigny) recovered from the stratotype of the Tarabuco Formation of Bolivia form a complete series of growth stages providing a good opportunity for reconstructing its ontogenetic development. The fact that juvenile specimens of C. antisiensis are nearly indistinguishable from adult individuals of Harringtonina australis Boucot strongly suggests that Clarkeia evolved from Harringtonina by the heterochronic process of peramorphosis. On the other hand, adult specimens of both the Brazilian Anabaia paraia Clarke and the Precordilleran specimens of Anabaia never exceed the youngest ontogenetic stage of Harringtonina australis, to which share small hinge plates supported by a septalium-like structure and absence of cardinal process. The overlap of adult morphology of Anabaia with the juvenile morphology of Harringtonina australis allows interpreting this succession as an evolutionary lineage showing increasingly more peramorphic characters. This hypothesis is supported by the correlation between the stratigraphic record of taxa and the inferred developmental sequence being Anabaia the oldest member (Early Silurian), Harringtonina australis the intermediate form (Wenlock-Ludlow), and Clarkeia antisiensis the youngest (Pridoli). This interpretation raises a systematic problem because the leptocoeliids Anabaia and Harringtonina are currently classified within the superfamily Uncinuloidea whereas Clarkeia is placed among the Rhynchotrematoidea. If the hypothesis is proven, these superfamilies, as presently constituted, would be polyphyletic groups.Fil: Leone, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

An in situ shelly fauna from the lower Paleozoic Zapla diamictite of northwestern Argentina: implications for the age of glacial events across Gondwana

A shelly fauna from the upper part of the Zapla glacial diamictite includes thelingulate brachiopod Orbiculoidea radiata Troedsson, the rhynchonelliforms Dalmanella cf. testudinaria (Dalman) and Paromalomena sp., the bivalve Modiolopsis? sp., and the trilobite Dalmanitina subandina Monaldi and Boso. Both taphonomic and paleoecologic data indicate a lack of transport reflecting the original community. The assemblage is closely comparable to the widespread latest Ordovician Hirnantia-Dalmanitina fauna. The Hirnantian age of the Zapla diamictite is further corroborated by the record of the northern Gondwana chitinozoans Spinachitina cf. oulebsiri Paris and Desmochitina minor typicaEisenack. The graptolites and chitinozoans from the overlying Lipeón Formation indicate that the postglacial transgression took place in the earliest Llandovery (P. acuminatus Biozone). According to the tectonosedimentary evidence, the Early Silurian age of the Cancañiri and San Gabán diamictites of north-central Bolivia and south Peru based on their palynological record is more likely the age of posglacial gravity flows and not that of the glaciation. We support the hypothesis that the weakly lithified glacigenic deposits ofHirnantian age were reworked and redistributed by high-energy marine processes during the postglacial transgression and then transported to the adjacent deep-marine trough. Ironrich horizons have been recognized in many basins of southern South America reflecting eustatic and paleoclimatic fluctuations. Most of them formed during the early stages of the postglacial transgression at the Ordovician/Silurian transition and are associated with low sedimentation rates and condensed intervals. The mild maritime postglacial climate, the increasing atmospheric CO2, and possibly the presence of incipient vegetated areas led toextensive weathering of glacigenic sediments supplying iron into the marine system to form ferruginous deposits. The sea level fall related to the peak of glaciation is recorded by both paleovalley incision and a sharp subaerial to subglacial unconformity. The transgressive systems tract starts with fluvio-estuarine deposits within incised valleys followed by widespread deposition of subtidal to open marine organic-rich shales onlapping regionally the basement rocks. The recognition of key stratigraphic markers (e.g. sequence boundary, flooding surface, ferruginous beds), alongside reliable micro and macropaleontological evidence allow a more accurate correlation between the Central Andean Basin of Peru, Bolivia and NW Argentina, the W Puna region, the Paraguayan and Brazilian sectors of the Paraná Basin, the Precordillera Basin of W Argentina, and the Cape Basin of South Africa.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Halpern, Karen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: de la Puente, Graciela Susana. Universidad Nacional del Comahue. Facultad de Ingeniería. Departamento de Geología y Petróleo; ArgentinaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentin

Una asociación disaeróbica de braquiópodos del Ordovícico medio (Darriwiliano) del terreno precordillera,argentina: implicaciones para la colonización temprana de las aguas profundas

A rapid increase of water depth associated with dysoxic bottom conditions took place in the central part of the Precordillera basin during the middle Darriwilian. The peak of transgression and drowning of the carbonate ramp are marked by the transition from the uppermost carbonate beds of the San Juan Formation to a rhythmic alternation of graptolitic black shales and marlstones (base of the Los Azules Formation). This lithofacial change is associated to a drastic faunal shift involving a renewal of the ecologic structure. The carbonate facies dominated by filter-feeding organisms were rapidly replaced by new communities characterized by benthic and pelagic trilobites and low-richness assemblages of minute brachiopods. Two main associations are recognized in the Los Azules Formation: a basal ephemeral Sivorthis- Mendolaspis Association and a more persistent Chilcorthis-Palaeoglossa Association inhabiting deeper and more dysoxic sea-bottoms. The new plectorthoid family Chilcorthidae is established to include the new genus Chilcorthis. Five new species are described: Palaeoglossa minima sp. nov., Cyrtonotreta vasculata sp. nov., Philhedra pauciradiata sp. nov., Sivorthis precordillerana sp. nov., and Bockelia canalis sp. nov. Associate taxa are Anomaloglossa? sp., Cyrtonotreta? sp., Protohesperonomia? sp., Syntrophia? sp. and unidentified Finkelnburgiidae, Polytoechiidae and Aegiromenidae. The first successful deep-water incursions are Floian?Dapingian in age, but from the Darriwilian they have been documented in several paleoplates. These pre-Sandbian brachiopod communities were more restricted geographically than the global Foliomena Fauna with which they share some taxa and similar morphotypes but differ in the higher proportion of linguliform brachiopods and less diverse plectambonitoidsA rapid increase of water depth associated with dysoxic bottom conditions took place in the central part of the Precordillera basin during the middle Darriwilian. The peak of transgression and drowning of the carbonate ramp are marked by the transition from the uppermost carbonate beds of the San Juan Formation to a rhythmic alternation of graptolitic black shales and marlstones (base of the Los Azules Formation). This lithofacial change is associated to a drastic faunal shift involving a renewal of the ecologic structure. The carbonate facies dominated by filter-feeding organisms were rapidly replaced by new communities characterized by benthic and pelagic trilobites and low-richness assemblages of minute brachiopods. Two main associations are recognized in the Los Azules Formation: a basal ephemeral Sivorthis-Mendolaspis Association and a more persistent Chilcorthis-Palaeoglossa Association inhabiting deeper and more dysoxic sea-bottoms. The new plectorthoid family Chilcorthidae is established to include the new genus Chilcorthis. Five new species are described: Palaeoglossa minima sp. nov., Cyrtonotreta vasculata sp. nov., Philhedra pauciradiata sp. nov., Sivorthis precordillerana sp. nov., and Bockelia canalis sp. nov. Associate taxa are Anomaloglossa? sp., Cyrtonotreta? sp., Protohesperonomia? sp., Syntrophia? sp. and unidentified Finkelnburgiidae, Polytoechiidae and Aegiromenidae. The first successful deep-water incursions are Floian–Dapingian in age, but from the Darriwilian they have been documented in several paleoplates. These pre-Sandbian brachiopod communities were more restricted geographically than the global Foliomena Fauna with which they share some taxa and similar morphotypes but differ in the higher proportion of linguliform brachiopods and less diverse plectambonitoids.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; Argentin

Braquiópodos del ordovícico superior de la formación San Benito, Cordillera del Tunari, Bolivia

The brachiopod fauna from the San Benito Formation of Bolivia, of late Sandbian-Katian age, is restudied on the basis of material collected in the Cordillera del Tunari. The new heterorthid genus Tunaria is erected to include the species Orthis berthoisi? var. erratica Davidson, 1869 (formerly attributed to Drabovinella) from England, France and Spain, and the new species Tunaria cocksi from Bolivia. The fauna also includes the first record in South America of Rafinesquina pseudoloricata (Barrande), and Hirnantia cf. transgrediens (Havlíek). Overall, the low diversity San Benito fauna corroborates the Mediterranean biogeographic signature of Central Andean brachiopod assemblages.Se describe la fauna de braquiópodos de la Formación San Benito de Bolivia, de edad Sandbiano tardío–Katiano, en base a material coleccionado en la Cordillera del Tunari. Se erige el nuevo género Tunaria para incluir la especie Orthis berthoisi? var. erratica Davidson, 1869 (anteriormente atribuida a Drabovinella), registrada en Inglaterra, Francia y España, y la nueva especie de Bolivia Tunaria cocksi. La fauna también incluye Hirnantia cf. transgrediens (Havlíček) y el primer registro en América del Sur de Rafinesquina pseudolori- cata (Barrande). En su conjunto, esta fauna de baja diversidad corrobora la signatura biogeogeográfica Mediterránea de las asociaciones de braquiópodos de la región Andina Central.Fil: Benedetto, Juan Luis Arnaldo. Universidad Nacional de Cordoba; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; Argentina

Tunariorthis, a New Substitute Name for Tunaria Benedetto, 2013 (Brachiopoda, Heterorthidae)

THE generic name Tunaria was erected by Benedetto (2013) to include the species Orthis berthoisi? var. erratica Davidson, 1869, from England, France and Spain, and the new species Tunaria cocksi Benedetto, 2013, from the Late Ordovician San Benito Formation of Bolivia. According to the ICZN (1999, Art. 53, 60) Tunaria Benedetto, 2013, must be rejected and replaced with a new name because it is a junior synonym of the linguloidean brachiopod Tunaria von Hoek, 1912, p. 247 (type species Tunaria cochabambina), non Link, 1807, which was renamed as Tunarites by Cooper and Muir-Wood (1951). The name Tunaria was used subsequently by Pirán (1957) to designate an acanthosomatid hemiptera from Bolivia (type species Tunaria andicola Pirán 1957) which is also a junior synonym of the cnidarian Tunaria Link 1807. Therefore, the new name Tunariorthis nom. nov is proposed to substitute the illegitimate name Tunaria.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Presence of punctae in the ‘plectorthoidean’ brachiopod Famatinorthis turneri (Middle Ordovician) from western Argentina: implications for early diversification of punctate orthides

Famatinorthis Levy & Nullo is a distinctive orthide brachiopod of Dapingian age from the volcaniclastic rocks of the Famatina Range of western Argentina. Although it was originally classified among the plectorthoideans, a new collection from the La Escondida Formation has yielded exceptionally well-preserved moulds of Famatinorthis turneri in which silicified infillings of punctae are clearly visible, leading to the reassignment of the genus to the dalmanellidines. In this paper, phylogenetic analyses are used to determine the evolutionary relationships of Famatinorthis, the Tremadocian linoporellid Lipanorthis, and other Ordovician Gondwanan genera. The placement of Plectorthoidea in the same major clade as linoporellids, and the separation of Dalmanellidina as an independent clade are the most important features of all shortest trees, supporting the idea that linoporellids may have originated from a plectorthoid ancestor. Cladistic analysis reveals that Lipanorthis lies close to the ancestry of the linoporellid lineage, and Famatinorthis clusters within the more derived taxa of the clade with which it shares a large septalium. It seems that the presence of endopunctae in the orthides does not necessarily indicate close phylogenetic relationships as it could have occurred at different times in different clades. If the homoplasic nature of endopunctae in the order Orthida is supported by further morphologic and phylogenetic studies, the fundamental division of orthides in non-punctate (Orthidina) and punctate (Dalmanellidina) may need revision. h Brachiopods, Ordovician, Gondwana, Famatina, phylogeny, punctate orthides.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Gatosella, a new basal plectambonitoid brachiopod with undercut cardinal process from Middle Ordovician limestones of the Precordillera terrane, Argentina

The plectambonitoid brachiopod Gatosella muricata gen. et sp. nov. is described from the uppermost nodular limestones of the San Juan Formation. The well-constrained early Darriwilian age of these beds leaves Gotosella as one of the oldest known plectambonitoideans possessing an undercut cardinal process. A phylogenetic analysis of representative genera bearing this character reveals that the new Precordilleran genus is a basal member of the subfamily Aegiromeninae (as presently defined). Parsimony analysis supports the existence of three subclades which may be considered as having familial rank in the Linnaean classification: Aegiromenidae, Hesperomenidae and Sowerbyellidae, and also indicates that the xenambonitins are more closely related to the sowerbyellids than to any other group. Copyright © 2012 The Natural History Museum.Fil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin