Kainella Walcott, 1925 (Trilobita, Early Ordovician) in Northwestern Argentina and Southern Bolivia. Systematic Paleontology. A taxonomic study is presented involving different species of Kainella from the Central Andean Basin. These early Tremadocian species come from the Santa Rosita, Cardonal, and Devendeus formations, and also from the Guayoc Chico Group; all units lie exposed at numerous localities in the Argentine Cordillera Oriental. Also analyzed are Kainella species from the Iscayachi Formation exposed in the Yunchará Segment in southern Bolivia. A group of eight species is recognized, suggesting a significantly greater diversity than previously assessed. An emmended diagnosis of K. meridionalis Kobayashi is provided, and a lectotype is designated. On this basis, some of the former assignments to this species are now rearranged into the taxa described herein. Complete morphological information is provided on K. andina Suárez Soruco, based on new collections from its type locality (Cuesta de Erquis), and from Argentina. The new species K. teiichii sp. nov., K. morena sp. nov., Kainella sp. nov. A and Kainella sp. nov. B are described and illustrated. Also, K. colombiana Harrington and Kay from the Güéjar Group (Tremadocian-Floian, Sierra de La Macarena, Colombia) is tentatively referred to Naustia Ludvigsen of Late Cambrian age.

Kainella Walcott (trilobita, Early Ordovician) In Northwestern Argentina And Southern bolivia. Biostratigraphic Significance. The Tremadocian Kainella meridionalis Zone in the Central Andean Basin is is reassessed. This zone has been widely used for regional and intercontinental correlations, but such correlations mostly involved an extended interval that corresponds, in fact, to the whole range of the genus. Species of Kainella recorded in northwestern Argentina and southern Bolivia exhibit a relatively wide geographic distribution and a constrained stratigraphic range. On the basis of their record a succession of biozones is proposed, ranging from the basal Tremadocian to possibly the early middle Tremadocian. Three biozones are proposed on the basis of integrated information drawn from several localities, i.e., the K. andina, K. meridionalis, and K. teiichii zones. In addition, the Jujuyaspis keideli Subzone is here upgraded to the rank of zone. The definition of this succession of biozones is a significant progress in the establishment of a high resolution biostratigraphic framework based on trilobites, leading to more precise correlations in the future.

Expansion of the geographical and temporal range of Elochelys convenarun (Chelonii Bothremydidae) from de Upper Cretaceous of the Iberian Peninsula. The Campanian and Maastrichtian chelonian fauna of Western Europe was mainly composed of endemic taxa. The Bothremydidae-represented by the genera Rosasia, Foxemys, Polysternon and Elochelys-are very abundant in this record. Elochelys is known through relatively scarce material consisting only of isolated plates and carapaces, which are presently assigned to two species, i.e., Elochelys perfecta and Elochelys convenarum. In France, two specimens from the Campanian of Fuveau, Provence, have been assigned to the species Elochelys perfecta; one carapace is now taken to be the holotype of the species, while the anterior half of another carapace was described as the paratype. The holotype of Elochelys convenarum consists of a carapace from the upper Maastrichtian at Cassagnau-2 (Haute-Garonne), and specimens from the upper Campanian-lower Maastrichtian at Fox Amphoux, Provence, have been tentatively assigned to this genus. In Spain, the only reference to this genus is ?Elochelys sp. from the upper Campanian fossil site of Laño, in Treviño County, Burgos. Abundant specimens of pleurodiran turtles have been recognized at the new Upper Cretaceous fossil locality of Lo Hueco (Fuentes, Cuenca, Spain). Herein, we refer to Elochelys convenarum a carapace from this site. This carapace is the most complete specimen referred to Elochelys and constitutes the first robust evidence of the presence of this genus in the Iberian Peninsula, expanding the chronostratigraphic distribution of the species to the late Campanian-early Maastrichtian.

Floian chitinozoans (Lower Ordovician) from the Santa Victoria area, Cordillera Oriental, north-western Argentina. Part 2. Biostratigraphic, paleobiogeographic and paleoenvironmental implications. This is the first study of the Floian chitinozoans in the Acoite Formation exposed at Quebrada La Huerta and Quebrada Grande, Santa Victoria area, northeastern end of the Argentinian Cordillera Oriental (Salta Province). Biostratigraphic analysis of this group is calibrated with the graptolite zones Tetragraptus akzharensis, “Baltograptus deflexus” and Didymograptellus bifidus, previously established in the area and ranging from the latest early Floian to the late Floian. Chitinozoans are also calibrated with acritarchs that include some species of the messaoudensis-trifidum assemblage, among others. According to the most recent studies on chitinozoans conducted in Northwestern Argentina two biostratigraphically meaningful chitinozoan assemblages are proposed for the Santa Victoria area, i.e., Lagenochitina sp. A (early middle Floian) and Eremochitina baculata brevis? (late Floian). The latest early Floian-latest middle Floian chitinozoan assemblages reveal affinities with North Gondwana and South China whereas the late Floian chitinozoan assemblages are cosmopolitan. Distribution of the studied Early Ordovician chitinozoan assemblages suggests that the development of the active thermohaline oceanic circulation for this portion of the Western Gondwana margin—globally recorded in the Middle Ordovician—occurred earlier than in other regions. Chitinozoans also reveal paleoenvironmental differeces between the eastern and central outcrop belts in the Central Andean Basin, Northwestern Argentina.

Thrombolites (microbial reefs) of the form-genus Favosamaceria in the Upper Cambrian of the Eastern Precordillera, San Juan, Argentina. In the upper part of the La Flecha Formation (Furongian, Upper Cambrian) of the eastern Precordillera, Argentina, there are abundant, metre-sized, domical patch-reefs flanked by peloidal and intraclastic grainstone. These shallow-water reefs are thrombolites and they consist of a radial-columnar microbial framework composed mainly of clotted micrite with subordinate micrite, peloids and lumps. In between the framework elements are intraclastic and bioclastic peloidal grainstones. In longitudinal section the framework appears as upward-radiating, branching and anastomosing columns which in transverse section range from roughly circular, elongate, lobate, or labyrinthiform in outline. Morphologically they conform to the form-genus Favosamaceria Shapiro and Awramik. However, despite partial dolomitization, they do not exhibit the distinct secondary microstructure diagnostic of the type form-species, F. cooperi Shapiro and Awramik. Accordingly, the thrombolites are placed in a new taxon -F. precordillerana forma-sp. nov.- which is characterized by a primary clotted and peloidal micritic microstructure.

A detailed study is carried out on the taxonomy of the bryozoan fauna from the upper levels of the San Juan Formation (Darriwilian) in the Talacasto and Cerro Viejo sections, Argentinean Precordillera. Three bryozoan genera are described and two new species are erected: Lamottopora multispinosa sp. nov., Aostiporn sanjuanensis sp. nov., and Phylloporinidae sp. indet. The paleoecological significance of the bryozoan fauna is discussed. The ramose bryozoans Lamottopora and Aostipora dominate in the Talacasto section. Some colonies probably lived attached directly to the substrate, while others occur attached to the surface of the abundant sponge fauna in the section. The majority of bryozoans at the Cerro Viejo section occur as epibionts, with bases attached to the surface of sponges. Bryozoans collected in the matrix are scarce compared to the Talacasto section, and comprise a few fragments of ramose bryozoans and two small fragments of the reticulate Phylloporinidae sp. indet were recorded exclusively in this locality. The presence of this delicate form in Cerro Viejo is further evidence of the quiet water conditions suggested for these levels. Only the laminar form Nicholsonella occurs in slightly older levels (Floian) of the San Juan Formation. The low diversity recorded here shows a slight decoupling with the global pattern. The first local radiation (three genera) is minor compared with the important radiation that the phylum experienced elsewhere.

Inferences about the diet of Miocene platyrrhine monkeys have relied upon the morphology of the molar teeth, specifically the crests on the molars. Using a library of Micro-CT images of a broad comparative sample of living platyrrhines (callitrichines, cebines, pitheciids and atelids), late early Miocene Homunculus, and the early Miocene Tremacebus and Dolichocebus, we extend these inferences by examining the surface areas of the tooth roots, anchor points for the periodontal ligaments. From muscle scars on the skull, we estimate the mechanical leverage of the chewing muscles at bite points from the canine to the last molar. Extant platyrrhines that gouge bark to obtain exudates do not have especially large canine roots or anterior premolar roots compared with their less specialized close relatives. Extant platyrrhines that have more folivorous diets have much larger molar roots than do similar-sized more frugivorous species. Homunculus patagonicus has large postcanine roots relative to body size and poor masticatory leverage compared to the extant platyrrhines in our sample. The large postcanine roots, heavy tooth wear, and moderately-long shearing crests suggests a diet of abrasive, resistant foods. However, relatively poor jaw adductor leverage would have put the masticatory apparatus of Homunculus at a mechanical disadvantage for producing high bite forces compared to the condition in extant platyrrhines. Tremacebus and Dolichocebus, like Homunculus, have larger tooth root surfaces than comparable-sized living platyrrhines. They also resemble Homunculus in being more prognathic and having posteriorly-located temporalis origins - all features of a relatively poor leverage system.

This study analyzes taphonomic alteration of brachiopod shells, i.e., Bouchardia rosea (Mawe) from Ubatuba Bay, northern coast of São Paulo State, Brazil. The average age of the studied shell deposits is 674 years BP. The underlying hypothesis is that taphonomic signatures are not uniformly distributed along a bathymetric gradient. Assemblages were sampled using a Van Veen grab sampler (31 × 40cm) along transect of fourteen stations from zero (beach) to 35 m water depth. Four sedimentary environments were recognized: (a) beach, (b) protected bay with clay bottom, (c) protected bay with sandy bottom, and (d) inner shelf with sandy bottom. All brachiopod shells (i.e., total fraction including fragments) from each of the five stations with appreciable accumulations (up to 1607 shells) were investigated following a protocol of ten taphonomic signatures. Six of these ten taphonomic signatures (articulation, fragmentation, edge alteration, color alteration, bioerosion, and encrustation) were homogeneously distributed among studied environments, indicating that these general types of taphonomic signatures per se are not sensitive to environmental conditions in this case. On the other hand, shell surface texture varied along the bathymetric gradient, thus showing a high potential to be used in taphofacies analyses. Several examples of taphonomic generalizations available in the literature are neither applicable nor comparable to our results, which further confirm that overgeneralizations should be avoided in taphonomic studies.

Bite marks and injuries caused by intraspecific predation or aggressive social behavior are uncommon in fossil vertebrates, and in the fossil record of suchian archosaurs they are extremely unusual. A peirosaurid crocodyliform collected from the Upper Cretaceous beds of the Neuquén Group (northern Patagonia, Argentina) shows abundant bite marks and injuries. These injuries are spread across all the preserved parts of the specimen, with the highest concentration of bite marks, perforations and breakage in the caudal region. Characteristics of these injuries are analyzed, and their possible origin and related taphonomic aspects are assessed. Results indicate that the injuries were not produced by intraspecific fighting, but probably by the predating action of a theropod dinosaur.