A description of Colbertia lumbrerense Bond (Mammalia, Notoungulata) is presented. This species is recorded in levels of the Lumbrera Formation (Eocene) in northwestern Argentina. Several specimens were collected; yet its cranial osteology has not been studied in detail. The new description provided herein is based on five specimens, including the type specimen. The external surface of the posterior zone of the skull in this species shows a generalized notoungulate morphology. The development of certain elements (external auditory meatus, meatal crest, epitympanic sinus) is similar to that observed in other Paleogene notoungulates such as Simpsonotus Pascual, Vucetich, and Fernández; Brachystephanus Simpson, Minoprio, and Patterson; and Xenostephanus Simpson, Minoprio, and Patterson. In spite of this generalized arrangement, the skull shows some distinctive features, particularly in the petrosal. Some traits of this bone are shared with Dolichostylodon saltensis García López and Powell, a notoungulate recorded in upper levels of the same formation. The morphology described in this study is consistent with recent phylogenetic analyses of Paleogene notoungulate taxa that place C. lumbrerense in a basal position.

NEW POSTCRANIAL MATERIAL OF SAUROSUCHUS GALILEI REIG (ARCHOSAURIA: CRUROTARSI) FROM THE LATE TRIASSIC OF CENTRAL-WESTERN ARGENTINA. Saurosuchus galilei Reig is a “rauisuchid” from the Ischigualasto Formation (late Carnian, Late Triassic) located in central-western Argentina. This paper is the first detailed description of the proatlas-atlas-axis complex of this taxon, of a complete and articulated vertebral column, and of both scapulae. Overall morphology of the proatlas-atlas-axis complex is similar to that of other “rauisuchids”. This complex and the post-axial cervical vertebrae show the typical traits of an animal with a short and strong neck. The cervical vertebrae are anteroposteriorly compressed and dorsoventrally elongated. Vertebral laminae, interlaminar depressions, and lateral depressions on the centra are present in the cervical and dorsal vertebrae, as in other “rauisuchids”. The presacral series bears ventrally keeled centra and large transversal expansions of the distal ends of the neural spines. The caudal series shows axially compressed centra with a longitudinal ventral groove. The scapulae are very robust and have a brief expansion and a slightly curved scapular blade. The remarkable diversity of “rauisuchids” in general, makes a detailed analysis necessary in order to approach morphofunctional and phylogenetic problems; this new material is expected to contribute towards the solution of these problems.

An ichnological assemblage from the Middle Jurassic La Matilde Formation at Estancia Laguna Manantiales, Santa Cruz Province, Argentina, is exceptional both in diversity and abundance. It includes four dinosaurian ichnotaxa (Wildeichnus, Grallator, and the endemic Delatorrichnus and Sarmientichnus), the mammalian Ameghinichnus, several vertebrate tracks of uncertain ichnogeneric assignment and invertebrate and root cavities. Because of its importance, an updated ichnotaxonomic revision and a detailed study are needed. In this contribution, the dinosaur ichnogenera are revised and emended diagnoses of three of them are provided. Recorded together with ichnogenera originally named by Casamiquela —Delatorrichnus, Sarmientichnus and Wildeichnus— is the cosmopolitan Grallator. A few tracks of dubious assignment are described. Casamiquelichnus Coria and Paulina Carabajal, 2004, from the same locality, is a junior synonym of Sarmientichnus. The paleocommunity represented by the La Matilde ichnofauna was dominated by small-bodied species with high regenerative and resettling capacity.

ALTERATIONS IN LATE CRETACEOUS DINOSAUR EGGSHELLS FROM RÍO NEGRO, ARGENTINA. Abnormal dinosaur eggshells are described from the Allen Formation (Late Cretaceous) at Salitral de Santa Rosa (Río Negro Province). Two different types of abnormalities were identified, i.e., (1) eggshells with altered microstructure and heterogeneous ornamentation, among which can be distinguished (1a) eggshells without rosettes (in megaloolithids and faveoloolithids), and (1b) eggshells with rosettes (in faveoloolithids); and (2) multilayered eggshells (only in megaloolithids). In the first group (1a) the eggshells display a greater range of diameters than the normal ones and the surface nodules are overgrown by recrystallization. Thin sections show alterations of the normal eggshell structure of the units. In the second group (1b) eggshells present groups of flower-shaped nodules (or rossettes) on certain sectors of their surface. In thin sections it is possible to observe that the outline of the eggshell units is completely irregular, while the pore channels are corroded. Two identical layers were identified in the double eggshell (2), the externalmost of which is the thinnest and lacks growth nuclei. Cathodoluminescence analysis established that double eggshells and eggshells with heterogeneous ornamentation with rossettes have a pathological origin, while eggshells with heterogeneous ornamentation without rossettes are only strongly altered diagenetically.

VERTEBRAL MORPHOLOGY OF BOA CONSTRICTOR (SERPENTES: BOIDAE) AND THE VALIDITY OF THE MIOCENE GENUS PSEUDOEPICRATES AUFFENBERG, 1923. The vertebral morphology of the extant Neotropical snake Boa constrictor Linnaeus, is discussed on the basis of clearly described and illustrated characters that can be observed in isolated fossil vertebrae. Mid-precloacal vertebrae of B. constrictor are mainly characterized by a high neural spine; generally high and vaulted neural arch; robust and very high zygosphene, with a narrow basis; notched or concave anterior edge of zygosphene in dorsal view, without a medial protuberance or tubercle; long zygapophyseal articular facets oriented more laterally than anterolaterally, slightly inclined above the horizontal; constant presence of small paracotylar foramen; very short neural arch and vertebral centrum; and very thin, clearly defined, and prominent haemal keel. Posterior precloacal vertebrae are longer (neural arch and vertebral centrum) and have shorter zygapophyses, thinner zygosphene, and broader and less prominent haemal keel than the mid precloacal vertebrae. Based on the knowledge of the morphology of the vertebrae of B. constrictor and its intracolumnar and intraspecific variation, the genus Pseudoepicrates from the Miocene of Florida is synonymyzed with Boa. This implies that this genus reached the Greater Antilles and Florida during the Miocene, becoming later extinct in these areas.

Three new species of the Ataphridae are described here: Ataphrus mulanguiniensis sp. nov., Chartronella paganiae sp. nov. and Chartronella spiralis sp. nov.; in addition, another doubtfully referred member of the family is recorded from the studied sections, i.e., Lewisiella? sp. The new findings here reported from the Early Jurassic of Chubut Province contribute towards the knowledge on the systematics of the family in Argentina, extending its paleogeographic distribution into the Jurassic of South America. An abundant and diverse invertebrate fauna found in association with the ataphrid genera indicates a littoral marine environment for the gastropod-bearing rocks.

FORAMINIFERA FROM THE AGRIO FORMATION (LOWER CRETACEOUS), NEUQUÉN BASIN, ARGENTINA. Forty-six species of benthic foraminifera recovered from the Pilmatué and Agua de la Mula Members of the the Agrio Formation are described and illustrated. The genus Eomarssonella and Epistomina hechti Bartenstein et al. are recorded for the first time in the Neuquén Basin, and Trocholina infragranulata North is found in the central area of the basin. The stratigraphic range of Epistomina australis Masiuk and Viña, Reinholdella hofkeri (Bartenstein and Brand), Trocholina infragranulata North, Marssonella sp. and Marssonella subtrochus Bartenstein is expanded to both marine members of the Agrio Formation. Differences recognized in the foraminiferal assemblages suggest marginal marine to marine inner-middle shelf environments. Nutrients, oxygen and salinity fluctuations are observed throughout the sedimentary sequence.

The first description of insect-plant interaction in a Glossopteris flora from the Permian of Argentina (La Golondrina Formation, Santa Cruz) is presented. Four specimens are described; these are referred to Glossopteris browniana (Brongniart), G. damudica (Feistmantel), and G. sp. cf. G. ampla Archangelsky. Different types of interaction recorded include marginal feeding and oviposition. This is the first evidence of insect-damage in the flora from the La Golondrina Formation, and also presently the only formal description of this kind available for a Paleozoic megaflora in Argentina.

This paper analyzes evidences of predation observed in ostracod populations collected in the southwestern Spanish shelf (0–70 m depth). Examination of seventy-two samples and almost 17,300 specimens allowed recovering more than 135 bored valves and carapaces. Percentages of bored specimens are very low (< 2%), with the highest values in isolated samples with low to very low ostracod densities. Two main types of boreholes can be distinguished: a) Oichnus paraboloides Bromley, accounting for over 70% of the total boreholes; and b) Oichnus simplex Bromley. Boreholes are concentrated mainly in the central and dorsal areas of the valves. Borehole diameter shows a positive but not significant correlation with the sizes of the predated valves. This diameter is usually higher in shallow marine areas. Predation affects the most abundant species of this shallow marine environment (mainly adults and the last juvenile instars). Ornamentation seems to be secondary in the predatory strategy.