Six egg-filled depressions discovered in the Upper Cretaceous Anacleto Formation (Campanian) of Patagonia, Argentina, and interpreted as dinosaur nests, provide the only known evidence of titanosaurid sauropod nest construction. These nest trace fossils show truncation of sedimentary structures as well as differences in texture between the host substrate and in-filling sediment. Titanosaurid sauropods excavated and laid eggs in open nests rather than burying clutches in sediment. In addition, this paper establishes criteria for definitive recognition of excavated nests in the stratigraphic record.

An embryonic oviraptorid skeleton is described within an egg from the Late Cretaceous Djadokha Formation of Ukhaa Tolgod, Mongolia. The specimen comprises the ventral part of the skull and most of the mandible, a poorly preserved axial skeleton missing most of the tail, and portions of the forelimbs, shoulder girdles, pelvis, and hindlimbs. The skull is readily referable to the theropod dinosaur clade Oviraptoridae on the basis of several skull specializations (edentulous, vertically oriented premaxilla, a sinusoidally shaped lower jaw, and an unusual articulation of the vomer and premaxilla), and the postcranial skeleton is consistent with this identification. The egg is equivalent in overall shape and microstructure to those found beneath several oviraptorid skeletons recovered from the same formation. The skeleton is well ossified and, in comparison with ossification patterns in living Aves, the evidence suggests that this species was closer to the precocial end of the precocial-altricial spectrum of developmental patterns.

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The stratigraphy and age of a sauropod nesting ground containing the first definitive embryonic remains of sauropods preserved inside their eggs is analyzed. The fossil locality, called Auca Mahuevo, occurs in the Anacleto Member of the Río Colorado Formation in Neuquén Province, Argentina. The 5 m thick interval of overbank mudstones containing the fossilized eggs and embryos occurs near the middle of a 35 m sequence of thin, fluvial, concretionary sandstones and thicker units of silty sandstone. Flooding of shallow stream channels deposited overbank silt and mud on the eggs, killing the embryos and initiating the process of fossilization. Egg fragments containing patches of fossilized integument were found as float weathering out of the mudstone on local flats. Complete eggs containing embryonic bones and teeth were quarried from a steep ridge where the mudstone was exposed.Twelve paleomagnetic samples collected throughout the lower 30 m of the section establish the presence of a Reverse geomagnetic polarity interval. This constitutes the first magnetostratigraphic characterization for this part of the Río Colorado Formation and for the late Cretaceous sequence of formations that comprise the Neuquén Group. Biochronologic age estimates for the Río Colorado fauna combined with the Reverse polarity determinations for the fossiliferous sediments in the Anacleto Member argue for an age younger than the long

Rahonavis ostromi, a paravian from the Maastrichtian Maevarano Formation, Mahajanga Basin, northwestern Madagascar, preserves morphology germane to understanding the character transformations present among paravian theropods, and in particular, among those non-avialan theropods most closely related to birds. The holotype specimen consists of a partial axial column (including cervicodorsal, dorsal, sacral, and caudal vertebrae and chevrons), most of the hind limbs and pelvis, and a partial forelimb (scapula, ulna, radius). Additional isolated elements referred to Rahonavis include distal humeri, a partial dentary, and a second right ulna; the duplicate right ulna demonstrates that at least two individuals of Rahonavis are present in the collection. All specimens of Rahonavis were recovered from the same level in quarry MAD 93-18 in 1995. All elements are described in detail and illustrated in multiple views, including CT slices of select elements to demonstrate internal morphology. Recent phylogenetic analyses place Rahonavis either within the non-avialan Unenlagiinae, an early-diverging clade within Dromaeosauridae, or at the base of Avialae. Rahonavis is one of the best represented and preserved Gondwanan paravians, and remains a pivotal taxon for understanding the evolution and biogeography of paravians.