Esta tese aborda a geobiologia do único Atol do Oceano Atlântico Sul. Diferentes classificações foram realizadas para o complexo recifal de Rocas ao longo dos séculos XIX e XX, as quais são avaliadas historicamente. Análises biogeomorfológicas e de mapeamento das unidades recifais foram realizadas no Atol das Rocas para a compreensão da dinâmica sedimentar e do relevo deste recife oceânico. Os diferentes compartimentos recifais são afetados por processos biogeomorfológicos como controle de processos erosivos, bioproteção, bioerosão recifal, bioturbação, cimentação de areia carbonática biogênica, produção de sedimentos biodetríticos e bioconstrução (principalmente de algas calcáreas, corais, vermetídeos e foraminíferos). Organismos diversos incluindo aves, peixes, tartarugas, corais, zoantídeos, algas, moluscos, poliquetas, sipunculídeos, foraminíferos e microorganismos agem nos diferentes grupos de processos biogeomorfológicos gerando as características únicas do Atol. O recife oceânico se desenvolveu provavelmente nos últimos 7000 anos do Período Neógeno. A paleohidrodinâmica da corrente oceânica, variações no gradiente de energia no lado a barlavento e sotavento e, sobretudo, as oscilações eustáticas holocênicas foram preponderantes na evolução recifal. Em níveis de mar alto uma grande laguna composta por comunidades bentônicas se formou com grande diversidade biológica. Eventos regressivos e de erosão por ação de ondas e correntes levou as feições observadas atualmente, tais como o ambiente lagunar raso (<6m profundidade), de um amplo depósito arenoso e das ilhas à sotavento. A dinâmica temporal e espacial de sete comunidades principais de ambientes submersos, intertidais e emersos é demonstrada pela primeira vez. / This thesis approaches the geobiology of the only Atoll in the South Atlantic Ocean. Different classifications were made for Rocas Reef Complex along the nineteenth and twentieth century, which are evaluated historically. Biogeomorphological analysis and mapping of the reef units were done on the Rocas Atoll for the comprehension of the sedimentary dynamic and of the relief of this oceanic reef. The different reef compartments are affected by biogeomorphological processes such as erosive process control, bioprotection, bioerosion, bioturbation, cementing of the biogenic carbonate sand, production of biodetritic sediments and bioconstruction (especially of calcareous algae, vermetids, corals and foraminifers). Different organisms including birds, fishes, turtles, corals, zoanthids, algae, mollusks, polychaets, sipunculids, foraminifers and microorganisms act in the different groups of biogeomorphological processes generating the unique characteristics of the Atoll. The oceanic reef developed over the past 7000 years in the Neogene Period. The paleohydrodynamic of the oceanic current, variations of the gradient of energy on the leeward/windward side and, above all, the eustatic holocenic oscillations were predominant in the reef evolution. In high sea levels a lagoon composed by bentonic communities formed with great biological diversity. The regression and erosion by waves and currents led to the formation of shallow lagoon environment, extensive sandy deposit and the Islands in leeward side. The temporal and spatial dynamic of seven main communities of underwater, intertidal and emerged environments is shown for the first time.

Dicinodontes (Therapsida: Anomodontia) compreendem os principais herbívoros do intervalo Permiano Médio-Triássico Superior. Algumas de suas características morfofuncionais cranianas têm se mostrado boas adaptações à herbivoria e ao eficiente processamento oral de materiais vegetais, bem como à termorregulação. Dentre estas, a aquisição da propalinia (movimentação ânteroposterior da mandíbula) e a substituição de um aparelho mastigatório com dentes por uma ranfoteca cobrindo boa parte da extremidade anterior do crânio são os mais característicos. Na anatomia corpórea como um todo, a aquisição de uma postura mais ereta (upright), o aumento do tamanho corpóreo e a presença de turbinais são indicativos de que o grupo evoluiu para um padrão de vida mais ativo e, consequentemente, com um maior gasto energético. Neste trabalho, é apresentada uma revisão bibliográfica sobre tais adaptações e uma discussão sobre sua origem e evolução no clado Anomodontia, focando a espécie Jachaleria candelariensis Araújo & Gonzaga, 1980 do Triássico Superior do Rio Grande do Sul, Brasil. / Dicynodonts (Therapsida: Anomodontia) comprise the main herbivores of the Middle Permian - Upper Triassic interval. Some of their morphological and functional cranial characteristics revealed to be adaptations to herbivory and efficient oral processing of plant materials, as well thermoregulation. Among these, the acquisition of propaliny (anteroposterior movements of mandible) and the replacement of the teeth by a ramphoteca covering most of the snout are the most characteristic adaptations. Regarding to their overall shape, the acquisition of a more erect (upright) gait, the increase in body size and the presence of turbinals indicate that this group evolved toward a more active lifestyle and, consequently with a most energetic cost. In this dissertation, is presented a bibliographic revision about such adaptations and a discussion about its origin and evolution within Anomodontia, focusing the Upper Triassic Jachaleria candelariensis Araújo & Gonzaga, 1980, from Rio Grande do Sul State, southern Brazil. / Los dicinodontes (Therapsida: Anomodontia) fueron los principales herbívoros durante el intervalo Pérmico Medio - Triásico Tardío. Presentaban varios caracteres morfofuncionales que reflejan adaptaciones al hábito herbívoro, así como a la termoregulación. Entre las más comunes están la adquisición de la propalinía (movimentación antero-posterior de la mandíbula) y la sustitución de un aparato masticatorio con dientes post-caninos por uno con forma de pico cubierto por una ranfoteca. Otros caracteres como la adquisición de una posición mas erecta (upright), aumento de la talla corporal y la presencia de turbinales son indicativos de que el clado evolucionó hacia un patrón de vida mas activo, y consecuentemente, de un mayor consumo de energía. En este trabajo se realizó una revisión bibliográfica de dichas adaptaciones y se discutió sobre su origen y evolución dentro del grupo Anomodontia, con un enfoque en el taxon Jachaleria candelariensis Araújo & Gonzaga, 1980 del Triásico Tardío de Rio Grande do Sul, Brasil.

Mollusk shells contain proteins within and between the crystals of calcium carbonate. These organic molecules play an important role in biomineralization and shell function, and their stable isotope ratios of carbon and nitrogen are also thought to record important ecological information about the animal's diet and nutrient sources. These proteins can be preserved for millions of years, offering potential insight into pre-anthropogenic ecological conditions. However, shell organics in older shells are typically recovered in reduced abundances due to leaching and remaining organics are often converted from insoluble proteins to soluble, free amino acids, making them difficult to detect and recover. Therefore, demineralization and organics-capture methods must be optimized for yield to extract much-needed ecological information from older shells. This project compared insoluble and soluble organic yields of modern gastropod Strombus alatus shells demineralized with acids of varying concentrations and temperatures. Results suggested that demineralizing shell fragments with 0.1 M HCl at a ratio of 0.9 L HCl/g of shell was optimal. Average percent organic yields ~0.2% for modern and ~0.06% for fossil Strombus spp. Future applications of this work include using this refined method to reconstruct food webs across broad temporal scales.

The Neogene history of Caribbean deep-sea benthic foraminifera was investigated by calculating changes in paleoproductivity, diversity and paleobiogeography ~26 to 2 Ma, which includes the progressive closure of the Central American Seaway. Three hypotheses were tested: (1) Paleoproductivity values prior to closure of the Central American Seaway are similar in both the Caribbean and equatorial Pacific and then diverge by the time of early shoaling events; (2) Diversity values of benthic foraminifera prior to the closure of the Central American Seaway were similar in the Caribbean and EEP, and had changed by the time of early shoaling; and (3) during the Miocene and into the Pleistocene, the progressive constriction of the CAS affected deep-sea benthic foraminiferal assemblages by increasing their dissimilarity between the Caribbean and equatorial Eastern Pacific. These hypotheses were tested with 104 samples from five Caribbean and EEP deep-sea cores by calculating paleoproductivity with multiple proxies, determining diversity indices and calculating biogeographic similarity coefficients. The data supported the first two hypotheses: The greatest change in paleoproductivity occurred at ~8 Ma during seaway constriction, when values diverged between the Caribbean and EEP. After complete seaway closure at ~4 Ma, the Caribbean became oligotrophic, noted by a decrease in high-organic flux species, and an increase in Nuttalides umbonifera, an indicator species. The largest changes in species-level diversity occurred with the barrier to deep-water flow at ~12 Ma, and Caribbean diversity increased at ~8 Ma with seaway constriction. However, the third hypothesis was rejected: Increases in assemblage similarity actually occurred during most major paleoceanographic events, with the only decrease in Caribbean-EEP similarity occurring at ~12 Ma, coincident with a drop in diversity and emplacement of the Panama isthmian sill. Thus, the barrier to deep-water flow at ~12 Ma affected the composition of tropical American benthic foraminifera more than the largest change in paleoproductivity at ~8 Ma, or closure of the Central American Seaway at ~4 Ma.

Weasels and mink (Mustela and Neogale) can be difficult to distinguish osteologically due to similarities in morphology, thus suggesting the need for an accurate tool in distinguishing among taxa. This study utilized a combination of character state and stepwise discriminant function (DFA) analyses to examine potential distinguishing features of skull and tooth morphology. Measurements and ratios were collected from all 18 extant musteline species, as well as the extinct Neovison macrodon, Mustela rexroadensis, Mustela meltoni, Mustela gazini, and Mustela jacksoni. Unidentified musteline specimens from the Gray Fossil Site were also included. Results of the character state analysis and DFA proved fairly reliable in distinguishing both extant and fossil taxa. The character state analysis revealed six useful morphological characters to aid in distinguishing between genera while the DFA demonstrated reliable separation of genus, species, and clade. For both analyses, morphology of the carnassials (P4, m1) and M1 contributed most to distinction.

The tudlov amber has been the only known fossil resin from the Czech Republic, in which the biological inclusions are preserved, and at the same time the only Czech fossil resin occurring not in the area of the Bohemian Massif, but in outer arch of the Outer Western Carpathians. So far, only single findings of fossil Hymenoptera and Diptera have been published. In contrast to mostly Cretaceous ambers of the Bohemian Massif, the age of tudlov amber is usually estimated from the late Paleocene to mid Eocene. This diploma thesis provides an overview of the fossil organisms found in the tudlov amber in the past two decades and it is also the most comprehensive text dedicated to the palaeodiversity of embedded organisms from this remarkable fossil resin. The presence of various microscopic fungi is proven, as well as the presence of angiosperm trichomes, mites and insects (prevailed by Hymenoptera and Diptera). The discovery of a hymenopteran family Stigmaphronidae (Apocrita) is the first Cenozoic evidence of this family, formerly considered as extinct by the end of Cretaceous. Finding of an isolated gymnosperm twig with wood anatomical characters close to genus Glyptostrobus allows to outline some conclusions about the paleoecosystem. The Eocene age of the resin is confirmed by the combination of...

The quantification of disparity is an important aspect of recent macroevolutionary studies, and it is usually motivated by theoretical considerations about the pace of innovation and the filling of morphospace. In practice, varying protocols of data collection and analysis have rendered comparisons among studies difficult. The basic question remains, How sensitive is any given disparity signal to different aspects of sampling and data analysis? Here we explore this issue in the context of the radiation of the echinoid order Spatangoida during the Cretaceous. We compare patterns at the genus and species levels, with time subdivision into subepochs and into stages, and with morphological sampling based on landmarks, traditional morphometrics, and discrete characters. In terms of temporal scale, similarity of disparity pattern accrues despite a change in temporal resolution, and a general deceleration in morphological diversification is apparent. Different morphometric methods also produce similar signals. Both the landmark analysis and the discrete character analysis suggest relatively high early disparity, whereas the analysis based on traditional morphometrics records a much lower value. This difference appears to reflect primarily the measurement of different aspects of overall morphology. Disparity patterns are similar at both the genus and species levels. Moreover, inclusion or exclusion of the sister order Holasteroida and the stem group Disasteroida in the sampled morphospace did not affect proportional changes in spatangoid disparity. Similar results were found for spatangoid subclades vis-à-vis spatangoids as a whole. The relative robustness of these patterns implies that the choice of temporal scale, morphometric scheme, and taxonomic level may not affect broad trends in disparity and the representation of large-scale morphospace structure.

Many organisms are known to reach high levels of endemism and biodiversity in the temperate forests of Southern Appalachia, especially in the dense forests and rugged terrain of the Blue Ridge physiographic province. Many plants and fungi reach their highest levels of biodiversity in these mountains, as does one group of vertebrates: the lungless salamanders, Plethodontidae. This family of salamanders hosts the most species of any other group of salamanders on earth and has adapted to a wide range of habitats. Only two of the approximately twenty-seven known genera are not found in North or South America, and while we know much about the modern-day biology of this family, few fossils older than ~15,000 years have been recovered, complicating our understanding of the historical distribution of this group and the timing of key evolutionary events within the family. Recently discovered salamander fossils from the Gray Fossil Site provide the foundation of this project. We describe these exceptionally large plethodontid remains to a new genus that belongs to the group containing dusky salamanders, or desmognathans. The morphology of the fossil material resembles Phaeognathus hubrichti, an extant burrowing species from southern Alabama with a suite of primitive characteristics. Comparison of the fossil material to modern desmognathans using geometric statistical methods has revealed that the extinct form was likely similar in lifestyle to P. hubrichti, but considerably larger. It was unparalleled in the southern Appalachians in terms of size and ecology, and reveals a more complex evolutionary history for desmognathan salamanders.

Endocranial morphology provides evidence of sensory ecology and sociality of extinct vertebrates. The Earliest Pliocene Gray Fossil Site (GFS) of NE Tennessee features a conspicuous dominance of skeletal elements belonging to the dwarf tapir, Tapirus polkensis. Numerous individuals in one fossil locality often suggests gregarious behavior, but sociality in T. polkensis contradicts behavior documented for extant Tapirus species. I test T. polkensis for variation in sensory and social ecology using computed tomography and 3D digital endocasts from an ontogenetic sequence. I compare the T. polkensis endocasts with extant Tapirus species using Encephalization Quotients (EQs) and 3D geometric morphometrics. Results show conserved endocast morphology for Tapirus, and thus, conserved sensory and social ecology. Tapirus behavior is likely consistent for ~5 Ma, and extant Tapirus behavior can be inferred for T. polkensis. The large number of individuals from the GFS is likely the result of a preservation bias unrelated to gregariousness.

The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. This study consists of three parts: conservation of wood remains, identification of taxonomic groups represented by the fossil wood, and measuring the organic content of fossil wood from the Gray Fossil Site. When excavated, wood specimens from the site are saturated due to a high local water table. After testing seven different techniques to dry wood specimens, wrapping a specimen in string and allowing it to dry slowly was the method least likely to cause warping and cracking. Microscopic examination of wood cross sections reveal tree rings with distinct anatomical features, with implications for taxonomic identification. Tentatively identified taxa that are present at the Gray Fossil Site are similar to those present in pre-modern forests of northeastern Tennessee. Finally, loss on ignition tests indicate that the Gray Fossil Site wood lacks extensive permineralization or mineral replacement. The presence of alpha-cellulose, albeit stained with iron oxides, illustrates the potential for future stable isotope analyses.