Bouchardia rosea, a vanishing brachiopod species of the Brazilian platform: taphonomy, historical ecology and conservation paleobiology

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Appendicular robusticity and the paleobiology of modern human emergence

The emergence of modern humans in the Late Pleistocene, whatever its phylogenetic history, was characterized by a series of behaviorally important shifts reflected in aspects of human hard tissue biology and the archeological record. To elucidate these shifts further, diaphyseal cross-sectional morphology was analyzed by using cross-sectional areas and second moments of area of the mid-distal humerus and midshaft femur. The humeral diaphysis indicates a gradual reduction in habitual load levels from Eurasian late archaic, to Early Upper Paleolithic early modern, to Middle Upper Paleolithic early modern hominids, with the Levantine Middle Paleolithic early modern humans being a gracile anomalous outlier. The femoral diaphysis, once variation in ecogeographically patterned body proportions is taken into account, indicates no changes across the pre-30,000 years B.P. samples in habitual locomotor load levels, followed by a modest decrease through the Middle Upper Paleolithic.

Chaetopterid tubes from vent and seep sites: Implications for fossil record and evolutionary history of vent and seep annelids

Vestimentiferan tube worms living at deep-sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube's surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps—as well as a number of fossil tubes from shallow-water environments—also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient “vestimentiferans” based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities.

Antropologia Funerária e Paleobiologia das Populações Pós-Medievais Portuguesas: Os Casos de Nossa Senhora da Anunciada e Espírito Santo

As desigualdades sociais na saúde constituem a problemática abordada nesta dissertação, tendo sido escolhidas para explorar esta questão duas séries esqueléticas – igreja de Nossa Senhora da Anunciada (Setúbal) e capela do Espírito Santo (Loures) – cronologicamente enquadradas no período pós-medieval, entre os séculos XVI e XIX, e cujos indivíduos apresentavam estatutos socioeconómicos diferenciados. Na concretização deste objectivo foi realizada uma primeira abordagem que incidiu no estudo integral – contexto funerário e Paleobiologia – das respectivas séries. Do manancial de resultados obtidos foram seleccionados e explorados na segunda abordagem indicadores de estatuto social e de estatuto biológico (ou esqueléticos de stress fisiológico) capazes de responder à problemática enunciada, procurando demonstrar-se que as desigualdades sociais podem actuar sobre factores fundamentais ao desenvolvimento normal e saúde dos indivíduos, manifestando-se, consequentemente, de forma diferencial entre indivíduos de estatutos socioeconómicos contrastantes. A caracterização geral do contexto funerário revelou que no interior da igreja de N. Sra. da Anunciada, localizada no bairro do Troino, habitado por um segmento da população socialmente mais desfavorecido, registaram-se 93 inumações primárias e 155 secundárias, as quais foram realizadas em covas abertas no subsolo e revelando a quase ausência de espólio votivo e de caixão. Por outro lado, na capela do Espírito Santo foram exumadas 46 inumações primárias e 30 secundárias que foram exclusivamente encontradas em criptas, tendo os indivíduos sido inumados em caixão e identificando-se, igualmente, a presença de espólio votivo associado. A documentação histórica refere o nome de mecenas e benfeitores do respectivo convento com direito a sepultura na sua capela. Na caracterização paleobiológica geral foram revelados os perfis biológicos básicos, tendo sido identificados indivíduos de ambos os sexos e diferentes classes etárias, constatando-se em ambas séries esqueléticas a predominância de indivíduos do sexo feminino. A análise morfológica evidenciou os caracteres discretos e métricos, bem como a estatura dos indivíduos, sendo esta última, igualmente, referida no estudo das desigualdades sociais. Por fim, o estudo paleopatológico revelou a presença de diversas alterações dentárias e ósseas, incluindo condições enquadradas nos indicadores esqueléticos de stress fisiológico. Na segunda abordagem que se centrou no objectivo específico desta investigação, os indicadores de estatuto social – local de inumação, caixão e espólio votivo – mostraram uma associação dos indivíduos com o seu estatuto socioeconómico clara e inequívoca, enquanto os indicadores esqueléticos de stress fisiológico – crescimento, estatura, cáries, perda de dentes ante mortem, hiperostose porótica, cribra orbitalia, hipoplasias lineares do esmalte dentário, formação de osso novo bilateral nas tíbias, fracturas, osteoartrose, discartrose, alterações nas áreas das enteses e DISH – revelaram que a sua interpretação é muito complexa. Concluiu-se que a interpretação das desigualdades sociais na saúde com base em indicadores de estatuto biológico deve ser prudente, já que não é evidente uma associação ii directa com o estatuto socioeconómico dos indivíduos. Esta investigação corroborou a informação histórica e arqueológica que permite aludir ao estatuto socioeconómico dos indivíduos destas séries esqueléticas, mas a associação deste estatuto a uma saúde diferenciada entre grupos revelou-se inconclusiva.

Patterns of hominin occupation and cultural diversity across the Gebel Akhdar of Northern Libya over the last ~200 kyr

Excavations at Haua Fteah cave in Cyrenaica, Libya, have revealed a cultural sequence that may span the last glacial–interglacial-glacial cycle. The TRANS-NAP project has been re-excavating Haua Fteah and conducting geoarchaeological survey of an ecologically diverse landscape that includes the fertile Gebel Akhdar and littoral, pre-desert, and desert biomes. A major aim of this project is to characterize cultural and environmental changes across the region and correlate the surface archaeology with that from Haua Fteah. To date, 181 sites have been recorded, ranging from the Middle Stone Age (MSA) to Late Stone Age (LSA). Their geographic distribution suggests temporal variation in patterns of hominin habitat preference, with significantly more LSA than MSA sites at higher elevations. The surface archaeology also points to substantial spatiotemporal technological variation within the MSA. These patterns may be explained by both paleoenvironmental change and paleodemographic shifts in the region, resulting in a variety of hominin adaptive responses.

Quantitative comparisons and models of time-averaging in bivalve and brachiopod shell accumulations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Major developments in conulariid research: problems of interpretation and future perspectives

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Quantitative estimates of time-averaging in terebratulid brachiopod shell accumulations from a modern tropical shelf

Quantitative estimates of time-averaging in marine shell accumulations available to date are limited primarily to aragonitic mollusk shells. We assessed time-averaging in Holocene assemblages of calcitic brachiopod shells by direct dating of individual specimens of the terebratulid brachiopod Bouchardia rosea. The data were collected from exceptional (brachiopod-rich) shell assemblages, occurring surficially on a tropical mixed carbonate-siliciclastic shelf (the Southeast Brazilian Bight, SW Atlantic), a setting that provides a good climatic and environmental analog for many Paleozoic brachiopod shell beds of North America and Europe. A total of 82 individual brachiopod shells, collected from four shallow (5-25 m) nearshore (<2.5 km from the shore) localities, were dated by using amino acid racemization (D-alloisoleucine/L-isoleucine value) calibrated with five AMS-radiocarbon dates (r(2) = 0.933). This is the first study to demonstrate that amino acid racemization methods can provide accurate and precise ages for individual shells of calcitic brachiopods.The dated shells vary in age from modern to 3000 years, with a standard deviation of 690 years. The age distribution is strongly right-skewed: the young shells dominate the dated specimens and older shells are increasingly less common. However, the four localities display significant differences in the range of time-averaging and the form of the age distribution. The dated shells vary notably in the quality of preservation, but there is no significant correlation between taphonomic condition and age, either for individual shells or at assemblage level.These results demonstrate that fossil brachiopods may show considerable time-averaging, but the scale and nature of that mixing may vary greatly among sites. Moreover, taphonomic condition is not a reliable indicator of pre-burial history of individual brachiopod shells or the scale of temporal mixing within the entire assemblage. The results obtained for brachiopods are strikingly similar to results previously documented for mollusks and suggest that differences in mineralogy and shell microstructure are unlikely to be the primary factors controlling the nature and scale of time-averaging. Environmental factors and local fluctuations in populations of shell-producing organisms are more likely to be the principal determinants of time-averaging in marine benthic shelly assemblages. The long-term survival of brachiopod shells is incongruent with the rapid shell destruction observed in taphonomic experiments. The results support the taphonomic model that shells remain protected below (but perhaps near) the surface through their early taphonomic history. They may be brought back up to the surface intermittently by bioturbation and physical reworking, but only for short periods of time. This model explains the striking similarities in time-averaging among different types of organisms and the lack of correlation between time-since-death and shell taphonomy.

Significado paleobiológico de agrupamentos (coloniais/ gregários) de Conularia quichua Ulrich, 1890 (Cnidaria), Formação Ponta Grossa, Devoniano (Pragiano-Emsiano), Bacia do Paraná, Brasil

The Conularia beds of the Ponta Grossa Formation (Devonian) of the Paraná Basin, southern Brazil, yield well-preserved specimens of Conularia quichua Ulrich and Paraconularia africana Sharpe. Many of these are preserved in life orientation. Also, one of the C. quichua specimens has five faces instead of four, providing additional evidence of a cnidarian affinity for conulariids. Conulariids occur in the Jaguariaíva Member (or Sequence B, transgressive system tract) containing several obrution deposits beneath marine flooding surfaces. Taphonomic data obtained from these beds show conclusively that both C. quichua and P. africana were epibenthic, sessile invertebrates originally oriented with their long axis perpendicular to the bottom and with their aperture opening upward. Of the 136 C. quichua specimens examined here, 125 occur isolated. Eleven of the C. quichua specimens collectively occur in five discrete clusters consisting of two or three specimens. All of the clustered specimens are fully inflated (exhibiting a rectangular transverse cross section) or slightly compressed longitudinally. In all of these specimens the apex is missing, and thus the problem of whether the clusters were clonal colonies or formed through preferential larval settlement cannot be resolved conclusively. However, in the single cluster consisting of three specimens, the specimens are oriented perpendicular to bedding, and thus they do not converge adapically. The three specimens are in contact with each other along the upper portion of their median region. These and the lack of any evidence of a sheet of budding stolons, suggest that this cluster was formed by preferential larval settlement. © Asociación Paleontológica Argentina.

Revisão cladística-filogenética e considerações paleobiogeográficas sobre sebecosuchia (metasuchia, crocodylomorpha), do cretáceo superior ao mioceno

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crowded Rosselia ichnofabric in the Early Devonian of Brazil: An example of strategic behavior

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An Analysis of Anchitherine Equids Across the Eocene–Oligocene Boundary in the White River Group of the Western Great Plains

Anchitherine horses are a subfamily of equids that are abundantly represented in the late Eocene and early Oligocene of North America. This group has been heavily studied in the past, but important questions still remain. Some studies have focused on the Eocene-Oligocene boundary and have used these equids along with other taxa to study mammalian diet and climate change through this interval. I reexamine two anchitherine genera, Mesohippus and Miohippus, from stratigraphic sequences of the White River Group in western Nebraska and southwestern South Dakota. These sequences span the Chadronian (late Eocene), Orellan (early Oligocene), and Whitneyan (early Oligocene) North American land-mammal ages. The most recent revision of these genera was done by Prothero and Shubin (1989). I review the characters used for taxonomic identification. This includes characters such as the hypostyle, the articular facet on the third metatarsal, and dental dimensions. To avoid possible biases caused by combining specimens from different stratigraphic levels, specimens were separated by location and stratigraphic level. The length and width of cheek teeth, and tooth rows were measured on 488 specimens. First molar area serves as a proxy for body mass in horses and other mammals, and can be useful for distinguishing among species. Results indicate that the characters used by Prothero and Shubin were highly variable in anchitherine horses and are not useful for distinguishing between these genera. The development of the articular facet on the third metatarsal may be a function of body size and therefore may be of no more utility than first molar area. Variability in first molar area suggests the presence of three species in the medial and late Chadronian, two species in the Orellan, and at least two species in the Whitneyan. Due to a lack of objective criteria separating Mesohippus from Miohippus, I recommend synonymy of these genera, making Mesohippus a junior subjective synonym.