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Pachycymbiola brasiliana is a marine snail found in the seas adjacent to the coasts of Brazil, Uruguay, and Argentina, whose eggshells are composed primarily of chitin. In this work, Pachycymbiola brasiliana eggshells were used to prepare films and their structural and physicochemical characteristics were investigated. The main focus was on their mechanical stability, water sorption, and methylene blue rejection. From the FTIR spectra, the bands corresponding to chitin were identified. The differential scanning calorimetric (DSC) data showed that the biopolymer has a glass transition temperature of around 32 °C. The morphological analysis was carried out by using SEM and XRD. The study of the films' mechanical stability showed an improvement with an increase in water activity. Regarding the methylene blue separation processes, a low permeation through the film and a rejection rate of 94 to 99% were demonstrated. Therefore, Pachycymbiola brasiliana eggshell can be considered a promising source of biopolymers for preparing biodegradable, non-toxic films with valuable separative properties. [ABSTRACT FROM AUTHOR]

The calcitic eggshell units of amniote eggs are underlain by a soft organic layer, the Membrana Testacea (MT), which has a mesh-like texture consisting of fibrils of organic material. Because of its soft anatomy, the MT is rarely preserved in fossils and only a few fossil reports of MT are known so far. Here we report the preservation of a mineralized MT layer in titanosaur eggshells recovered from a marlstone facies interbedded with the Deccan lava flows exposed near Piplanarayanwar village of Chhindwara District, Madhya Pradesh state in Central India. The MT layer is mesh-like, resembling protein membranes of extant reptiles and the MT reported in titanosaurid eggshells of the Upper Cretaceous Anacleto Formation at Auca Mahuevo, Argentina. The presence of tendrils and fibres of calcite in the MT layer testifies to the fact that the calcium layer represents the original fibrous MT. It also supports the view that fossilization of soft tissues like MT is possible because of the inferred anaerobic conditions that prevailed during the deposition of Piplanarayanwar intertrappean sediments in lacustrine or paludal bodies in a coastal-plain setting. [ABSTRACT FROM AUTHOR]

Experimental paleoparasitological approaches have been used in order to optimize the methodology previously to the application in archeological samples. In this study we evaluated the action of dehydration and local soil (Central Argentina) on the loss of parasite eggs in experimental coprolites, using two parasitological techniques: spontaneous sedimentation and sucrose-flotation. Experimental coprolites comprised fresh human feces, positive for Hymenolepis nana, Ascaris sp., and Enterobius vermicularis, submitted to controlled artificial dehydration. Experimental coprolites with soil addition were prepared by mixing archeological sediment with equal mass of fresh feces. Helminth eggs were counted and eggs per gram were estimated in each subsample. Statistical analyses were applied to compare subsamples before and after desiccation and with and without addition of soil sediment. The performance of parasitological methods statistically differed, the sucrose flotation technique being the less effective when fresh feces and experimental coprolites were analyzed. Partial deformation of eggs was observed via both techniques only in subsamples containing H. nana eggs. However, this was not seen in Ascaris sp. subsamples, possibly due to eggshell composition. We found that sample desiccation significantly decreased the number of eggs in the experimental coprolites. Mixing archeological sediment with the fecal material also resulted in significantly fewer eggs surviving, independent of desiccation. This shows that climate and soil in which archeological fecal samples are found can strongly influence the survival of parasite eggs from past populations. The small amount of parasite evidence often found in paleoparasitological analyses, including Central Argentina, could be attributed to the action of taphonomic processes rather than to the real absence of infection in these ancient populations. Importantly, the study highlights the role of local soil, confirmed for the first time by empirical data. The research provides valuable insights into the understanding of the paleoparasitological results of the region and of general paleoparasitology. [ABSTRACT FROM AUTHOR]

We report the youngest fossil egg of avian affinities from the Cretaceous (Allen Formation, Campanian-Maastrichtian) of Patagonia, Argentina. The fossil consists in most of the internal cast of a single egg, preserving some eggshell fragments on one of its poles. Its axes are 4.5 cm and 3.06 cm. The eggshell surface is smooth, and its thickness average is 400 µm. The eggshell has two layers, with an ornithoid basic type and a ratite morphotype. The well-developed mammillary layer is 154 µm thick, with petal-shaped mammillae, the continuous layer is 251 µm thick. Shell microstructure is consistent with Laevisoolithidae, an ootaxon traditionally associated with enantiornithid birds. The shape of fibers of the testaceous membrane (TM) is preserved; these are flattened, with a thickness of 1.1 µm and a width of 4.8 µm each. The arrangement of the fibers of the TM is random, similar to that observed in extant reptiles. EDAX analysis reported that fibers are enriched in traces of Mg, Al, Si, P, F, and K, elements that are also present in both extant and fossil shell membrane. Cladistic analysis performed is consistent with the avian affinities established on the basis of macro, micro and ultrastructural characteristics. [ABSTRACT FROM AUTHOR]

Concentrations of six trace metals were determined in the eggshells of American oystercatchers ( Haematopus palliatus ) from the Bahía Blanca estuary, Argentina. All metals measured in selected samples presented concentrations above the detection limit. Means found for Cu, Pb, Cr, Zn and Ni were as follow: 2.02 ± 0.52, 7.23 ± 2.33, 0.78 ± 0.03, 2.22 ± 1.13 and 6.05 ± 0.89 mg/kg dw. The mean concentrations of Cd found were surprisingly high: 13.28 ± 3.38 mg/kg dw. Previous studies made on prey items of the American oystercatchers showed low to medium concentrations of the six trace metals. This may indicate a possible transfer of the metals that are available in the environment through food chains. Our study indicates that American oystercatchers sequester heavy metals in their eggshells. Therefore the eggshells may be useful as biomonitors for trace metal contamination in the Bahía Blanca estuary. [ABSTRACT FROM AUTHOR]

The eggshell oospecies from India and Argentina are compared and reviewed in detail. These eggshells resemble each other in having a nodular outer surface ornamentation and clearly arched growth lines of the shell units. Microstructurally, the eggshell oospecies belonging to the oofamily Megaloolithidae shows fan-like shell units, which are sharply separated from each other throughout the thickness of the eggshell and can be traced up to the surface of the eggshell. Comparisons between four oospecies from India and Argentina reveal three groupings, which show similarities between megaloolithids of both countries: (1)Megaloolithus jabalpurensis,M. matleyiandM. patagonicus; (2)M. cylindricus,M. rahioliensisand Tipo 1d; and (3)M.megadermusand Tipo 1e. The other two types of eggshell oospecies from India and Argentina show partially fused external nodes and shell units. As a result, growth lines enter into the adjacent shell units with a marked concavity. A new oogenusFusioolithushave been erected due to fusion between shell units and tubospherulitic morphotype, which include two new oospeciesF. baghensisandF. berthei. Till date, morphostructurally, a total of 15 eggshell oospecies belonging to different oofamilies have been recorded from India and seven oospecies from Argentina. [ABSTRACT FROM AUTHOR]

Abstract: The Alvarezsauridae represents a branch of peculiar basal coelurosaurs with an increasing representation of their Cretaceous radiation distributed worldwide. Here we describe a new member of the group, Bonapartenykus ultimus gen. et sp. nov. from Campanian–Maastrichtian strata of Northern Patagonia, Argentina. Bonapartenykus is represented by a single, incomplete postcranial skeleton. The morphology of the known skeletal elements suggests close affinities with the previously described taxon from Patagonia, Patagonykus, and both conform to a new clade, here termed Patagonykinae nov. Two incomplete eggs have been discovered in association with the skeletal remains of Bonapartenykus, and several clusters of broken eggshells of the same identity were also found in a close proximity. These belong to the new ooparataxon Arriagadoolithus patagoniensis of the new oofamily Arriagadoolithidae, which provides first insights into unique shell microstructure and fungal contamination of eggs laid by alvarezsaurid theropods. The detailed study of the eggs sheds new light on the phylogenetic position of alvarezsaurids within the Theropoda, and the evolution of eggs among Coelurosauria. We suggest that plesiomorphic alvarezsaurids survived in Patagonia until the latest Cretaceous, whereas these basal forms became extinct elsewhere. [Copyright &y& Elsevier]

Abstract: Zooarchaeological research carried out on South-American ostrich eggshells from late pre-Hispanic site Arroyo Talainín 2 (ca. 1100–300BP, Sierras of Córdoba, Argentina) is presented in this paper. The resource importance has been assessed focusing mainly on its economic and political dimensions for social-unit integration rather than its classical use as a seasonal indicator. Eggshells taxonomic identification was performed by quantifying shell-pore density, and determining two Rheidae species: greater rhea (Rhea americana) and lesser rhea (Rhea pennata). High frequencies of burned eggshell fragments indicate an unequivocal association between this resource and the human occupations recorded at this site. Regional-scale data suggests that egg consumption took place disassociated from the main-residential camps. These locations were rock-shelters occupied by small-dispersed household groups or large-group food processing and consumption sites such as Arroyo Talainín 2. Thus, a flexible approach for a food-consumption study is required to account for its spatial dimension. Only a regional-scale archaeological research will allow advances to be made in our understanding of the subsistence patterns and socio-political organization of late pre-Hispanic human societies. [Copyright &y& Elsevier]

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Abstract: Twenty three different sites in two areas of Río Negro Province (Salitral Ojo de Agua and Salitral de Santa Rosa-Salinas de Trapalcó), preserving eggs and eggshells from the Allen Formation (Upper Cretaceous) were studied, and five egg levels were identified. Three different types of eggshell were recognized. Eggs possessing thick eggshells of Type 1 are abundant in both areas, sometimes associated with eggs having thinner shells. Eggs of eggshell Type 1 are included in the oofamily Faveoloolithidae of the parataxonomic classification. Eggshell Type 2 is subdivided into two groups (Types 2A and 2B), mostly based on the mean thickness of the eggshells and other parameters. Eggs of eggshell Type 2 are assigned to the oofamily Megaloolithidae of the parataxonomic classification, and ascribed to titanosaurs. A third type of eggshell (Type 3) is only recorded at one of the localities (Salitral Ojo de Agua, egg level 2). This type is intimately associated with theropod bones, and its microstructure agrees with an assignation to the Theropoda. It is assigned to the oofamily Elongatoolithidae. [Copyright &y& Elsevier]

Exceptionally preserved sauropod eggshells discovered in Upper Cretaceous (Campanian) deposits in Patagonia, Argentina, contain skeletal remains and soft tissues of embryonic Titanosaurid dinosaurs. To preserve these labile embryonic remains, the rate of mineral precipitation must have superseded post-mortem degradative processes, resulting in virtually instantaneous mineralization of soft tissues. If so, mineralization may also have been rapid enough to retain fragments of original biomolecules in these specimens. To investigate preservation of biomolecular compounds in these well-preserved sauropod dinosaur eggshells, we applied multiple analytical techniques. Results demonstrate organic compounds and antigenic structures similar to those found in extant eggshells. [ABSTRACT FROM AUTHOR]

Eggshells represent an important part of the fossil record of Titanosauria (Dinosauria – Neosauropoda) and their stable isotope compositions are valuable palaeoenvironmental proxies. A new set of conventional (δ18O and δ13C) and clumped (Δ 47) stable isotope compositions of titanosaurian eggshells is presented, together with that of a bone and a single associated tooth, sampled in three Late Cretaceous nesting sites from La Rioja Province, NW Argentina. The preservation state of the fossils was first evaluated using optical and analytical techniques, such as transmitted light and optical cathodoluminescence (CL) microscopy, energy dispersive X-ray spectroscopy (EDX), and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The isotopic compositions of the fossils were then compared to those of associated carbonate rocks and nodules, hydrothermal calcite and quartz, and those reported for eggshells from other nesting sites worldwide. This large, combined sample set allows us to define an isotopic hallmark (δ13C VPDB = −15 to −11‰; δ18O VSMOW = 27 to 33‰) typical for well-preserved mid-palaeolatitude titanosaurian eggshells. This hallmark is intended to identify the oological specimens best suited for palaeoenvironmental reconstructions, for instance in museum collection samples that may lack associated abiogenic materials such as host rocks. In addition, our isotopic data support that titanosaurians were animals with an elevated body temperature, mainly feeding on C3 plants, and reproducing under conditions more arid than the long-term average. The data are in excellent agreement with the isotopic data reported from other mid-palaeolatitude nesting sites around the world, indicating that titanosaurians needed similar environmental conditions to reproduce, regardless of the palaeogeographic location of their habitat. Finally, we raise the question whether titanosaurians experienced reproduction-related fasting, as noted for several extant vertebrates, and discuss the complexity of interpreting Δ 47 -derived temperatures, despite very consistent bulk isotopic data. [Display omitted] [ABSTRACT FROM AUTHOR]