The lithographic limestones of the Los Catutos Member (Vaca Muerta Formation, Neuquén Province, Argentina) (late middle—early late Tithonian) bear a great diversity of marine reptiles. These deposits are unique In the Southern Hemisphere as the record of lithographic limestones from the Upper Jurassic is restricted to the Northern Hemisphere, particularly to Western Europe. Some European basins are very close In age (late Kimmeridgian—early Tithonian) but they do not reach the middle—late Tithonian. Additionally, In the European basins the marine reptiles are mixed with continental biota whereas In Los Catutos Member the biota is exclusively marine, with the pterosaurs being the only exception. The strictly marine biota is composed by ichthyosaurs, two different species of turtles, one crocodyliform, and one plesiosaur. The taxonomic composition of Los Catutos Member is very similar to that found in Cerro Lotena (Portada Covunco Member, middle Tithonian) (Vaca Muerta Formation). These members share the same turtle species and one metriorhynchid genus, while ichthyosaurs only coincide at a family level. The study of marine reptiles from the Los Catutos Member, along with studies from other localities of the Neuquén Basin, have made an important contribution In filling the gaps In the evolutionary history of each of the represented clades. In this regard, they represent the only known marine reptiles from Gondwana throughout the Jurassic/Cretaceous transition, which Is poorly represented in other regions of the world.

Much of the current paleobiological knowledge on titanosaur sauropods was attained in just the last fifteen years, in particular that related to reproductive and developmental biology. Recent years have also seen progress on other poorly explored topics, such as pneumaticity, muscle architecture and locomotion, and endocast reconstruction and associated structures. Some titanosaurs laid numerous, relatively small Megaloolithidae eggs (with diameters ranging from 12 to 14 cm) in nests dug In the ground and, as known from the South American records, probably eggs of the multispherulitic morphotype. During ontogeny, certain titanosaurs displayed some variations in cranial morphology, some of them likely associated with the differing feeding habits between hatchlings and adults. The bone tissue of some adult titanosaurs was rapidly and cyclically deposited and shows a greater degree of remodeling than in other sauropods. Saltasaurines in particular show evidence of postcranial skeletal pneumaticity in both axial and appendicular skeleton, providing clues about soft tissue anatomy and the structure of the respiratory system. Titanosaurs, like all sauropods, were characterized by being fully quadrupedal, although some appendicular features and putative trackways indicate that their stance was not as columnar as in other sauropods. These anatomical peculiarities are significantly developed In saltasaurines, a derived group of titanosaurs. Compared with other sauropods, some titanosaurs seem to have had very poor olfaction but would have been capable of capturing sounds In a relatively wide range of high frequencies, although not to the extent of living birds.

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 plectambonitoids.

In order to reassess and amend previously published palynological data drawn from the Novo Remanso Formation, central Amazonia, we revisited the organic-rich samples from their work using systematic and quantitative biostratigraphic analyses, with possible implications in the biodiversity and paleoecological studies of Late Neogene deposits of Amazonia. In the study area, the Novo Remanso Formation is characterized by sandstones and mudstones deposited in a meandering river environment. The palynological assemblage comprises 46 morphotypes, including 21 species of pollen and 25 species of spores. Polypodiisporites usmensis, Retitrescolpites? irregularis and Mauritiidites franciscoi var. franciscoi, typical of lowland freshwater forests and shallow water lakes dominate the assemblage. Also, lower frequencies of Grimsdalea magnaclavata co-occur with Psilatricolporites crassoexinatus, Proteacidites triangulatus, Bombacacidites simpliciriloensis, Pteridaceoisporis gemmatus and Cingulatisporites laevigatus. Based on quantitative biostratigraphic techniques, the Novo Remanso Formation Is assigned a middle Miocene—Pliocene age In our study area. The presence of Elaterosporites klaszii (Albian-Cenomanian) In the Novo Remanso deposits strongly indicates Cretaceous rocks in the source-area, whereas absence of Andine palynomorphs may be indicative of a nearby source area for the deposits during the deposition of the Novo Remanso Formation.

We describe Equisetum dimorphum sp. nov. from the Lower Jurassic of Chubut Province, Patagonia, Argentina. This new species Is based on fertile and vegetative remains preserved as Impressions of stems, leaves, strobili, transversal sections of the stems showing their anatomy, and terminal pagoda-like structures. The fine-grained sedimentary matrix also preserved detailed Impressions of epidermal features. The morphological characters allow a whole-plant reconstruction and assignment to Equisetum. Equisetum dimorphum sp. nov. shows a mosaic of morphological characters that are commonly present in other Mesozoic forms and representatives of the two extant Equisetum subgenera, e.g., sunken stomata and a blunt strobilus apex. Compared to other well-known Mesozoic equisetalean taxa, Equisetum dimorphum sp. nov. appears to be most closely related to a group of Jurassic Equisetum-like plants including Equisetum laterale Phillips and Equisetites ferganensis Seward. Additional evidence for the morphological stasis of the fertile and vegetative organs of extant horsetails is supplied with this new material, adding further support to the hypothesis that the extant horsetails are a successful group that has undergone only little morphological changeover time and that has been present, nearly worldwide, since Jurassic times.

Sloth remains recovered from Actun Lak, Cayo District, Belize, during archaeological excavations by the Pacbitun Regional Archaeological Project include numerous though mainly fragmentary elements. Among the identifiable remains are a lower molariform tooth and several elements of the manus and pes. Although no complete cranial and long bone postcranial remains are available, the sloth is confidently assigned to the nothrotheriid species Nothrotheriops shastensis (Sinclair). This is the most southern certain record of the North American genus Nothrotheriops Hoffstetter and the first record of a nothrotheriid from Central America. Based on our knowledge of the species' diet and habitat preference from dry caves In the southwestern United States, its presence in Belize has paleoecological and biogeographic implications. The Belize remains clearly Indicate that sloth diversity in northern Central America was greater than previously suspected. They also suggest that a greater variety of habitats existed In this region during the Pleistocene, and that vegetation communities underwent more dramatic changes during this Interval than previously thought.