The Triassic paleoflora of cerro Cacheuta, Mendoza Province, Argentina. Bryopsida, Lycopsida, Sphenopsida, Filicopsida and Gymnospermopsida (Corystospermales and Peltaspermales). Four stratigraphic logs were measured in detail at the Cacheuta hill (northwestern Mendoza Province, Argentina), and seven plantiferous levels were determined at Puesto Míguez and Agua de las Avispas. The systematic study of the paleoflora found in these localities is presented in this paper. Bryopsida, Lycopsida, Sphenopsida, Filicopsida and Gymnospermopsida (Corystospermales y Peltaspermales) are analized in this first contribution. The systematic study include 25 taxa identified as Muscites guescelini Townrow, Pleuromeia sp., Equisetites fertilis (Frenguelli) Frenguelli, Neocalamites carrerei (Zeiller) Halle, Nododendron suberosum Artabe et Zamuner, Asterotheca truempyi Frenguelli, Cladophlebis copiosa Frenguelli, C. grahami Frenguelli, C. kurtzi Frenguelli, C. mendozaensis (Geinitz) Frenguelli, C. mesozoica (Kurtz) Frenguelli, Coniopteris harringtoni Frenguelli, Dicroidium argenteum (Retallack) Gnaedinger et Herbst, D. lancifolium (Morris) Gothan, D. odontopteroides (Morris) Gothan, D. pinnis-distantibus (Kurtz) Frenguelli, Zuberia feistmanteli (Johnston) Frenguelli emend. Artabe, Johnstonia coriacea (Johnston) Walkom, J. stelzneriana (Geinitz) Frenguelli, Xylopteris argentina (Kurtz) Frenguelli, X. elongata (Carruthers) Frenguelli, Scytophyllum argentinum (Frenguelli) Morel et al. comb. nov. emend., Pachydermophyllum dubium (Burges) Retallack, P. pinnatum (Walkom) Retallack and P. praecordillerae (Frenguelli) Retallack.

Biomechanical and morphofunctional study of the appendicular skeleton of Homalodotherium Flower 1873 (Mammalia, Notoungulata). Homalodotherium (Santacrucian- Friasian; early Miocene) is the best represented genus of the Family Homalodotheriidae (Notoungulata). It was proposed as a digging form, browser on trees in food habits, and with potential for adopting bipedal posture. The appendicular skeleton is studied morphometrical and biomechanically, considering proportions, principal bone accidents, and muscular insertions, comparing with extant mammals. Bone elements of the appendicular skeleton are described, the musculature reconstructed, and 10 morphometric measurements used for calculating eight functional indices. Indices include deltoid proportion and epicondilar development of the humerus, ulnar robustness and olecranon proportion, femoral and tibial robustness, and distal extension of the fore and hind limbs. The forelimb preponderates force development in humeral flexion and protraction of the limb, but it can develop speed movements in the distal portion of the limb. The hindlimb lies upon the lateral side of the autopodium, and has an important development of force for body support and ankle stabilization (flexion and adduction of the femur, limb flexion, extension of the pelvic girdle, zeugopodium flexion, and extension, inversion and reversion of the autopodium). Homalodotherium would be able of adopting a bipedal posture. An arboreal browser habit is supported, but digging habit is discarded. Possibility of speed flexion of the zeugopodium could indicate a use of the forelimb for defence.

Dentition of titanosaurs (Dinosauria, Sauropoda) from the Upper Cretaceous of Río Negro Province, Argentina: morphology, implantation and replacement. A fragment of dentary of a titanosaur sauropod from the Anacleto Formation (Upper Cretaceous of the Río Negro Province) is described. Inside the alveoli, functional and replacement teeth in successive “premature” stages are observed. At least in the preserved portion, an alternate teeth replacement pattern is observed. The histological analysis of this specimen allowed identifying the attachment dental tissues (alveolar bone, cementum and periodontal ligament). Numerous isolated teeth from the same unit and from the overlying Allen Formation are described. Based on these, a classification of the wear facets is proposed: 1) Teeth with only one facet: on the labial side, on the lingual side, or on the lateral side. 2) Teeth with two facets: the bigger on the labial side and the smaller on the lingual side; the bigger on the lingual side and the smaller on the labial side; the bigger on the lingual side and the smaller on the mesial or distal edge. 3) Teeth with three facets: one on the lingual side, the others on the mesial and distal edges; one on the lingual side, the others on the labial and mesial or distal edges; one on the labial side, the others on the mesial and distal edges. 4) Teeth with four facets: the smaller on the labial side, the bigger on the lingual side, and two lateral facets, one on the mesial and the other on the distal edges. Finally, we propose a hypothesis about the origin of the wear facets.

Palynology Of The Rio Bonito and Palermo Formations (lower Permian, Paraná Basin) in Candiota, Rio Grande Do Sul, Brazil: new data and biostratigraphic implications. New palynologic associations were recovered from an outcrop located at BR 293 Highway, between Bagé and Candiota municipalities, Rio Grande do Sul state, Brazil, related to the Rio Bonito and Palermo formations, Lower Permian of Paraná Basin. Eight samples were colected and studied, showing rich and diversified palynofloras. A total of 76 species were recognized, 42 corresponding to spores, 24 to pollen grains and 10 related to algae and fungi. Palynomorphs registered in the section here analysed indicate the recognition of the Vittatina costabilis and Lueckisporites virrkiae zones. Species with stratigraphic ranges limitated to Itararé Subgroup and Rio Bonito Formation were identified in a higher stratigrapical levels, meaning for instance, increasing on the stratigraphic range of these taxa. On the other hand, other stratigraphic interpretations are possible, constituting the scope of the present contribution.

We describe a new megaloolithid locality discovered near Coll de Nargó (Catalonia, northeastern Iberian Peninsula). Eggs at the Pinyes site occur within extensively developed, vertically-stacked paleosols of an alluvial system. Eight clutches were excavated and mapped and biological and taphonomic aspects recorded. Three-dimensional maps were constructed using a Trimble total station, supplementing traditional plan-view mapping to allow more accurate interpretation of egg and clutch distribution. The Megaloolithus siruguei eggs are compressed, presenting an ellipsoidal shape. The three-dimensional geometry of two large clutches suggests that the eggs were laid in shallow, bowl-shaped depressions. Tangential thin sections of eggshells also reveal abundant pores, consistent with incubation in a high humidity/ low oxygen environment. These data support previous inferences that M. siruguei eggs were buried in shallow pits.

Since 1991 when the coinciding occurrence of megaloolithid eggs and hatchlings of the hadrosaurid Telmatosaurus transsylvanicus was suggested by few limb bone remains found close to the first discovered eggs in the Hateg Basin, tens of eggs grouped in clutches together with neonate bones were unearthed within the place that become “Tustea nesting site”. In the meantime the original vertical escarpment near the village of Tustea was leveled and converted into a horizontal platform. By their external characters and eggshell microstructure all the eggs belong to the Megaloolithus oogenus, closer to M. siruguei; similarly, all the baby remains whose state of preservation allows their taxonomic assignment belong to Telmatosaurus transsylvanicus, one of the common dinosaur species from the rich Maastrichtian faunal assemblage of the Hateg Basin (Romania), and the basalmost hadrosaurid. Most of the baby remains consist of isolated bones and teeth, but partial skeletons with articulated elements were also found. The preliminary ontogenetic study reveals a rapid growth of the hatchlings, a fact also supported by the discovery of most of the skeletal remains outside the egg clutches, but in their close vicinity. In few cases bones were found within the egg clutches and even inside the egg. It is worth to mention that no sauropod remains were found within the nesting horizon from Tustea.

Outcrops of Anacleto Formation at Auca Mahuevo nesting site (Neuquén Province, Argentina) can be divided into two main sections. The lower section (51 m), exhibits a succession of point bar, levee, crevasse channel and crevasse splay deposits, typifing a fine-grained, mixed load, meandering fluvial system. Twenty five km toward south (Los Barreales locality) these deposits become progressively to distal floodplain facies. Egg-layers are exposed along this 25 km, however a higher concentration of egg-clutches occur into paleosols and abandoned channel deposits developed at ancient levee and meander belt areas. Lithofacial evidences allow attributing for this lower section semiarid climatic condition, with marked alternations of wet and dry seasons. Exceptional muddy sheet-floods burying the eggs and nests with a thick bed of mud, facilitating their preservation. The upper section (17 m), is composed by finer sediments of sloughs and lacustrine deposits developed over a poorly drained floodplain, under conditions of major aridity. South toward Los Barreales, evaporitic deposits was formed in saline-lakes. The tectonic and volcanic processes that affected the basin from the middle to upper Campanian were responsible for the variations in the environmental conditions during the latest phase of the Anacleto Formation deposition. Possibly, these changes provoked the abandonment of this area as nesting-ground.