Palynological, megafloral and mesofossil record from the Bajo Grande area (Anfiteatro de Ticó Formation, Baqueró Group, Upper Aptian), Patagonia, Argentina

The late Aptian flora of Baqueró is one of the best known and accurately dated Cretaceous plant associations from Gondwana, recognized for their well-preserved fossil remains. The Cerro Bayo (Bajo Grande area, Argentinean Patagonia) is one of its classical locations and includes the northernmost fossiliferous outcrops of the Baqueró Group, which belong to the Anfiteatro de Ticó Formation. It yields diverse and numerous plant megafossils and reproductive structures with associated pollen. We report a complete systematic study of a palynological association with 124 species, including 26 that are identified for the first time in the unit. This allowed the first record of three major botanical groups not reported before (i.e., lycophytes, hornworts and angiosperms), as well as algae and fungal spores. The same fossiliferous levels also yielded megafloral remains and the first record of a mesofossils assemblage for the Baqueró flora. By integrating all these floristic data sources, relative abundance analyses, and sedimentological data it is possible to propose a paleoenvironmental reconstruction of the Bajo Grande area during the late Aptian: a diverse forest growing in a temperate to warm climate with subtle variations between those associations from floodplains with water instability within a delta and those that grew into a more stable area out of the flooding influence. Thus, the presumed xeromorphic features identified in the Cerro Bayo flora (sunken stomata, papillae, epicuticular waxes) may have been related to contemporaneous volcanic activity recorded in Patagonia rather than to dry conditions.Fil: Llorens, Magdalena. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez Loinaze, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Vera, Ezequiel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

On the presence of the Cycad Pseudoctenis Dentata Archangelsky and Baldoni in the Punta del Barco formation (late Aptian), Santa Cruz province, Argentina

En el sur de América del Sur más de veinte especies de Pseudoctenis (Cycadales) han sido registradas en depósitos comprendidos entre el Triásico Superior y el Cretácico Inferior. Sin embargo, sólo tres especies, pertenecientes al Grupo Baqueró (Aptiano), conservan restos de cutícula. Uno de ellos, Pseudoctenis dentata Archangelsky y Baldoni, de la Formación Anfiteatro de Ticó (unidad inferior del Grupo Baqueró) se identifica aquí sobre la base de un nuevo espécimen bien conservado obtenido en depósitos del mismo grupo, pero en su unidad superior (Formación Punta del Barco). Este registro extiende la presencia de P. dentata en el Cretácico de Patagonia, a la vez que refuerza la importancia de considerar las características cuticulares en las asignaciones paleotaxonómicas.In southern South America more than twenty species, referred to the cycad genus Pseudoctenis, have been recorded from Upper Triassic to Lower Cretaceous deposits. However only three, identified from the Baqueró Group (Aptian), have cuticle preserved. One of them, Pseudoctenis dentata Archangelsky and Baldoni, from the Anfiteatro de Ticó Formation (basal unit of the Baqueró Group) is here identified on the basis of well-preserved material collected in the same Group, but in its upper unit (Punta del Barco Formation). This record extends the presence of this taxon in the Cretaceous flora of Patagonia and reinforces the importance of the cuticular features in paleotaxonomical assignations.Fil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Korallipteris, a new genus for Mesozoic Gleichenia-like fern fronds

A new morphogenus, Korallipteris, is proposed to accommodate fertile or sterile fern fronds possessing essentially Gleichenia-like morphology (e.g., pinnate fronds with small pecopteroid pinnules) but lacking diagnostic features that allow their classification at fern family-level. The aim is thus, to solve an old nomenclatural problem that involves the use of illegitimate genera, such as Gleichenites Goeppert and Microphyllopteris Arber. Several species of Gleichenites described from the Mesozoic of Argentina and Chile, and Microphyllopteris unisora Cantrill and Nagalingum from Antarctica are here reassigned to Korallipteris gen. nov. The proposal of Nagalingum and Cantrill to preserve Gleicheniaceaephyllum Crabtree emend. Nagalingum and Cantrill for true Gleicheniaceous ferns, diagnosed by having an arrested laminar bud, is here accepted.Fil: Vera, Ezequiel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Cátedra de Paleontología; ArgentinaFil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Gleicheniaceaephyllum San-Martini, a new name for Gleichenites San-Martini Halle Emend. Herbst 1962

The Cretaceous fern species Gleichenites san-martini Halle emend. Herbst is here combined to the genus Gleicheniaceaephyllum, since "Gleichenites" type specimens were transferred to pteridosperm taxa, and thus it is superfluous genus. Repository data of the holotype, as well as synonymy list, are also given.Fil: Vera, Ezequiel Ignacio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional de Rio Negro. Sede Alto Valle; Argentin

Lithraea australis (Berry) comb. nov. (Anacardiaceae) from the upper section of Ñirihuau Formation (middle Miocene), Patagonia

The first records of fossil plants from the Ñirihuau Formation (middle Miocene) were published by Edward Berry at the beginning of the last century. They consist of a small collection of leaf imprints obtained from the southern margin of the Ñirihuau River valley, western Río Negro, Argentina. Based on these records, Berry described a few ferns, gymnosperms and angiosperms. Among these impressions, stand out two specimens that Berry interpreted as pinnate leaves of Cycadaceae (now Zamiaceae) that he assigned to the new species Zamia australis Berry. However, after a review of Berry's original materials of Z. australis, and new specimens collected in recent years in the same fossil locality, it is concluded that these putative zamiaceous remains are in fact angiosperm leaves. They show great similarity with those of the current South American species Lithraea molleoides (Vell.) Engl. (Anacardiaceae). To encompass these remains, a new combination, Lithraea australis (Berry) is proposed. From a paleophytogeographic point of view, the recognition of a L. molleoides closely related species suggests that the plant communities of the upper section of the Ñirihuau Formation were part of the “Transitional Province” or at least constituted the ecotone between it and the “Nothofagidites” Province.Fil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Caviglia, Nicolás Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Vera, Ezequiel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; Argentin

Two new angiosperm leaf morphotypes from the Anfiteatro de Ticó Formation (mid-Aptian) Santa Cruz Province, Argentina

Floodplain deposits of the Anfiteatro de Ticó Formation (Baqueró Group, Aptian), in Patagonia (Argentina), are rich in plant remains and contain some of the oldest angiosperm records of southern Gondwana. Many gymnosperm and pteridophyte species, as well as three morphotypes of medium sized angiosperm leaves, have already been described from this unit at different fossiliferous outcrops. We report two new angiosperm morphotypes from the Bajo Tigre locality. Both morphotypes (AT1 and AT2) consist of nano- to microphyllous leaves, nearly elliptic, with untoothed margins and pinnate brochidodromous venation. These leaves mostly exhibit characteristics of a high first or low second rank vein system. This combination of characters is associated with early angiosperm evolution. Morphotype AT1 is similar to one of the brochidodromous morphotypes from the La Cantera Formation (uppermost Aptian), which could be possibly conspecific. Morphotype AT2 has gross features already observed in leaf records from the younger Kachaike Formation (Albian ̶ lower Cenomanian) though they differ in lamina shape and secondary venation features. The angiosperm leaves of the Anfiteatro de Ticó Formation suggest that the early stages of angiosperm evolution in Patagonia had included forms with more than one type of growth habit.Fil: Romero, Edgardo Juan. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Archangelsky, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

First megafloristic record for the Chubut Group at Somuncurá Canadón Asfalto Basin: An angiosperm dominated flora from the Upper Cretaceous Puesto Manuel Arce Formation, Patagonia Argentina

The first association of fossil plantimpressionsin the Chubut Group at the Somuncurá-Cañadón Asfalto Basin is described herein. Themid-Cretaceous megafloral assemblage from Patagonia, Argentina was recovered from the Puesto Manuel Arce Formation.The taphocenosis consists mostly of leaves preserved as impressions, although a variety of cuticle remains are also present. Angiosperms are both quantitatively and qualitativelythe main component of the flora (at least 9 leaf morphotypes recognized). A few ferns and conifers complete the plant assemblage.The angiosperm leaves exhibit physiognomic heterogeneity with a variety of well-defined venation patterns.The myrtophyll morphotype (Myrtoidea sp.) and palmatilobed palinactinodromous leaves (Bamfordphyllum crassivena gen. et sp. nov.) are significant components of the assemblage. Flora characters are consistent with the Cenomanian - earliest Turonianage proposed for the Puesto Manuel Arce Formation. Comparisons were made with coeval Patagonian and extra-regional floras which suggest both local as well as long-distance gondwanan links.Fil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Llorens, Magdalena. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Páez, Manuel Antonio. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The Chubut Group at the San Bernardo fold belt, Golfo San Jorge basin, Argentina: A review of fossil plant localities and its sedimentological setting

The Chubut Group (Cretaceous) consists of continental volcaniclastic deposits widely distributed in the Golfo San Jorge and Cañadón Asfalto basins of Central Patagonia. In the San Bernardo Fold Belt, numerous outcrops with fossil plants have been historically mentioned. In this contribution, a precise geographical and stratigraphic position of localities with megafloral records was carried out, identifying six plant localities. These fossil assemblages belong to the Matasiete, Castillo and Bajo Barreal formations (Chubut Group) covering a time span ranging from the Aptian ̶ earliest Turonian. The fossiliferous content of each flora is briefly characterized, and the sedimentological context is detailed. Most of these floras have been preserved in proximal floodplain facies, but also occurred as part of debris-flow deposits associated with fluvial channels with high discharge variability. The fossil assemblages are characterized by relatively low species richness. Angiosperms leaves are the main component and their physiognomic traits are homogeneous among floras prevailing microphyll, elongate, untoothed morphotypes. Few gymnosperms and ferns are also present. This study provides a general framework that will support future and more detailed paleobotanical studies, already underway, of each of these florasFil: Romero, Edgardo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Paredes, José Matildo. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Comodoro. Departamento de Geología; ArgentinaFil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Improntas foliares del Cretácico de la provincia de Santa Cruz, Argentina

Leaves imprints from the Cretaceous of Santa Cruz province, Argentina. An assemblage of imprints leaves of the fosiliferous locality Bajo de los Corrales, Santa Cruz province, Argentina is described. This assemblages comprise five angiosperm species, one gymnosperm and one pteridophyte. One of the angiosperm species is well represented, other materials are very scarce. The main species belongs to Myrtoidea patagonica Passalia, Romero and Panza gen. et sp. nov. in the Ochnaceous Alliance and the order Myrtales. It is a narrow elliptic blade, with entire margin and expanded petiole. It has a massive primary vein, irregular secondaries veins, which are almost as thin as the tertiaries veins, intersecondaries veins, and one or sometimes two intramarginal veins. It belongs to the Myrtophyll Morphotype (sensu Crabtree), and has Second Rank (following Hickey). The other species are poorly preserved, but show that the flora has rather diversified angiosperms. The assemblage is compared to Barremian-Coniacian floras from Baqueró Group, Chubut Group and Mata Amarilla Formation. It is suggested that it belongs to a sedimentary body different to the mentioned ones, probably of albian age.Fil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Romero, Edgardo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Panza, José L.. Servicio Geológico Minero Argentino. Delegación General Roca; Argentin

An Early Cretaceous zamiaceous cycad of South West Gondwana: Restrepophyllum nov. gen. from Patagonia, Argentina

The record of Cycadales in Patagonia begins in the Triassic and extends up to the Oligocene. In this region the group is highly diversified and includes several taxa represented by trunks, leaves and pollen cones. A new cycadalean genus and species, Restrepophyllum chiguoides, form the Aptian Anfiteatro de Ticó Formation, Santa Cruz province, Argentina, is described here. The fossil is a leaf compression with well-preserved cuticle. Its morphology, anatomy and ultrastructure are studied by means of light and electron microscopy. The leaf is lanceolate, serrate, and possesses a prominent midvein and decurrent laterals showing an open, simple or dichotomous venation. The leaf is hypostomatic, and the abaxial cuticle is thinner than the adaxial one. The stomata are irregularly distributed and indistinctly oriented between veins. They are monocyclic to imperfectly dicyclic (haplocheilic); the suprastomatal aperture is raised over the epidermis and the guard cells are sunken. Scattered trichomes and crystalliferous idioblasts are also present. The cuticle is composed of three layers: the outer and inner layers are lamellate, while the middle one is granulate. This new cycad leaf is compared with similar fossil leaves from Gondwana and Europe/North America, and also with similar extant cycad leaves. Based on the general morphology and the main characters of the cuticle, R. chiguoides is assigned to the family Zamiaceae; moreover it is more closely related to the living Zamia (Chigua) restrepoi (D. Stevenson) Lindstrom than to any other member of the Cycadales. Paleophytogeographic evidence suggests a South American origin of Zamia/Chigua and a further migration to northern latitudes. This new type of leaf also suggests the putative existence of a Chigua clade that may be traced back to the Early Cretaceous when two cycadalean families, Zamiaceae and Stangeriaceae, were already well-established in Patagonia.Fil: Passalia, Mauro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: del Fueyo, Georgina Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Archangelsky, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin