A new fossil species, Tsuga xianfengensis Xing et Zhou, n. sp., is reported based on two compressed seed cones. The fossil cones were discovered from the upper Miocene Xiaolongtan Formation at the Xianfeng Basin of Yunnan, southwestern China. The discovery of the Tsuga cones confirms the presence of Tsuga in the Miocene of central Yunnan and represents the earliest Tsuga macrofossils in the southwestern China. The new species reveals a close affinity with East Asian Tsuga species, T. chinensis and T. dumosa. It provides fossil evidence to support the molecular data that the Asian clade might be differentiated in the Miocene.

Quercus praedelavayi Xing Y.W. et Zhou Z.K. sp. nov. is reported from the upper Miocene of the Xianfeng flora in central Yunnan, southwestern China. The fossil species is identified based on the detailed leaf morphological and cuticular examinations. The primary venation is pinnate and the major secondary venation is craspedodromous with regular spacing. Stomata are anomocytic and occur on abaxial epidermis. Trichome bases are unicellular and multicellular. The new fossil species shows the closest affinity with Quercus delavayi, an extant species distributing in southwestern China. The responses of the functional leaf traits to the climate change were studied by comparing the leaf characters of fossil species and its nearest living relative. The stomatal density of Q. praedelavayi is higher than Q. delavayi, which suggests a lower palaeoatmospheric CO2 concentration during the late Miocene. The trichome base density of Q. praedelavayi is higher than the extant Q. delavayi. Considering the palaeoclimatic reconstruction of Xianfeng flora, it rejected the hypothesis that increase in trichome density is an adaptation to the drier environment.

A new fossil species, Tsuga xianfengensis Xing et Zhou, n. sp., is reported based on two compressed seed cones. The fossil cones were discovered from the upper Miocene Xiaolongtan Formation at the Xianfeng Basin of Yunnan, southwestern China. The discovery of the Tsuga cones confirms the presence of Tsuga in the Miocene of central Yunnan and represents the earliest Tsuga macrofossils in the southwestern China. The new species reveals a close affinity with East Asian Tsuga species, T. chinensis and T. dumosa. It provides fossil evidence to support the molecular data that the Asian clade might be differentiated in the Miocene.

Quercus praedelavayi Xing Y.W. et Zhou Z.K. sp. nov. is reported from the upper Miocene of the Xianfeng flora in central Yunnan, southwestern China. The fossil species is identified based on the detailed leaf morphological and cuticular examinations. The primary venation is pinnate and the major secondary venation is craspedodromous with regular spacing. Stomata are anomocytic and occur on abaxial epidermis. Trichome bases are unicellular and multicellular. The new fossil species shows the closest affinity with Quercus delavayi, an extant species distributing in southwestern China. The responses of the functional leaf traits to the climate change were studied by comparing the leaf characters of fossil species and its nearest living relative. The stomatal density of Q. praedelavayi is higher than Q. delavayi, which suggests a lower palaeoatmospheric CO2 concentration during the late Miocene. The trichome base density of Q. praedelavayi is higher than the extant Q. delavayi. Considering the palaeoclimatic reconstruction of Xianfeng flora, it rejected the hypothesis that increase in trichome density is an adaptation to the drier environment.

Twenty-one fossil foliage, identified as Fokienia shengxianensis sp. nov. (Cupressaceae), were collected from the upper Miocene Shengxian Formation in Tiantai and Ninghai counties, Zhejiang Province of eastern China. These fossils can likely be distinguished from other extant genera in the family Cupressaceae s.l. except Fokienia by leaf external morphology alone. Foliar cuticular comparison with the only modern species in this genus, Fokienia hodginsii Henry et Thomas, further suggests that the present fossil species closely resembles the modern counterpart. Paleoecologically, the occurrence of Fokienia from the Shengxian Formation appears to support that the fossil site was covered by subtropical evergreen broad-leaved forest and under warm and humid conditions during the late Miocene, consistent with evidence from previously published fossil plants.

In palaeopalynology oaks are rarely identified beyond the generic level. In order to recognize fossil evergreen and deciduous oak pollen, we compiled distinguishing criteria from the literature, most under the SEM, on the living oaks. One of the most significant criteria is the nature of the sculpturing under the SEM. Evergreen oak pollen exhibit at least four kinds of sculpturing, viz. rod-like elements, uniformly fine granules, scabrate-verrucate, and rugulate micromorphology. The first two types of sculpturing are mostly limited to the evergreen oaks and can be used to identify fossil evergreen oak pollen, while the last two types can also be seen in many deciduous oaks. On the other hand, deciduous oak pollen grains have relatively uniform sculpturing, with only two types encountered: scabrate-verrucate and rugulate sculpturing. This sculpturing is mainly present in deciduous oaks, despite its occurrence in some evergreen oaks. An absolute discrimination between evergreen and deciduous oak pollen is thus impossible and would require additional evidence in the form of macrofossils. The diagnostic criteria are applied to a Miocene pollen assemblage from Zhejiang Province, eastern China and demonstrate the high diversity of fossil oaks in the vegetation. The fossil pollen includes three morphotaxa of deciduous origin, two morphotaxa of evergreen habit, and three oaks whose habit is uncertain.

<p> About half the Caribbean hermatypic corals died out at the Oligocene-Miocene boundary, about 25 Ma. Roughly two thirds of those corals which died out in the Caribbean are still extant in the Indo-Pacific. The coral and coral associate faunas of three Upper Oligocene and three Middle Miocene fossil reefs in western Puerto Rico were compared. Corals on these sites suffered 59% generic extinction, and 54% species extinction. Nearly all coral genera which are tolerant of turbidity or turbidity and cold water survived. All corals found exclusively or principally on Oligocene shelf-edge reefs became regionally extinct. There are no shelf-edge reefs documented from the Miocene in the Caribbean.</p> <p> Coral associates, the endolithic organisms which live in coral skeletons, were almost completely unaffected by this extinction. Likewise, reef and off-reef gastropods, bivalves, and echinoids suffered only insignificant reductions in diversity. Only corals and large benthic foraminifera were strongly affected by the extinction. It is significant that zooxanthellate organisms were the primary victims of this extinction. There is no evidence to suggest effects at higher trophic levels.</p> <p> Paleontological evidence from corals, coral associates, and gastropods suggests enhanced upwelling in the Caribbean during the Miocene and Early Pliocene. This enhanced upwelling could account for the extinction by cooling Caribbean coastal surface waters and restricting reef development to on-shelf patch reefs, where corals would be subject to more intense sedimentation. Paleoceanographic models indicating West to East deep circulation through the Central American Seaway during the Miocene provide a mechanism for this enhanced upwelling.</p> <p> Life history characteristics may have influenced survivorship among the corals, but apparently had no effect on coral associates. Corals which brood their larvae survived in greater proportions than corals which broadcast. This pattern is opposite that observed in studies on molluscs and other invertebrates.</p> <p> This regional extinction was important in the division of a previously cosmopolitan reef fauna into the modern provincial faunas. Explaining this minor mass extinction may contribute to an understanding of the volatile record of reefs in the larger mass extinctions of the Phanerozoic.</p> / Thesis / Master of Science (MSc)

In geotechnical engineering, it has proven difficult to obtain reliable soil parameters for stiff clays. Laboratory testing results are often scattering due to the fissures and slickensides in these soils. Alternatively, in situ techniques offer a means to test the soils in place. This study focuses on in situ testing in Miocene stiff clays using an advanced nine strain arm self-boring pressuremeter (SBPM). This device was used to test the soils in both a self-boring and a simpler, non-boring mode (pre-bored or PBPM tests). The Miocene stiff clay was unique in that was sensitive and lacked of fissures and slickensides. The pressuremeter results could be compared to a range of other tests previously performed at the site. It is concluded that the SBPM provides accurate values of modulus and strength. Minor soil disturbance was found to have little effect when it could be anticipated. The simpler PBPM tests were not successful because of disturbance caused by borehole preparation. / Ph. D.

The Hyaenodonta include a wide variety of carnivorous mammals ranging in age from late Palaeocene to middle Miocene. Although they reached a nearly global distribution, little remains of them today. Many of the taxa are based only on teeth and jaw fragments. If we are to understand how these animals lived and evolved, we must therefore make the most out of the material we have. Herein, I report on the first nearly complete skull of Anasinopa leakeyi (Teratodontinae), which was recently found in Northern Kenya. The skull is dorsoventrally compressed, but otherwise relatively undamaged. The aim of this study was to provide a first glimpse of teratodontine brain morphology by reconstructing the neurocranium of this skull and creating a digital endocast. The result was one of the most well preserved endocasts of any hyaenodont known to date, with many of the cranial nerves and blood vessels visible. The size of the optic foramen relative to the size of the brain is similar to that of the extant wolf, Canis lupus, suggesting that A. leakeyi may have had a similar visual acuity. The body mass of A. leakeyi was estimated to up to 25 kg, meaning that it may have hunted small or large animals, perhaps having the ability to shift to larger prey when needed, as do extant, similarly sized, Felidae and Canidae. Endocasts are known from only a handful hyaenodont species, many of which were described by Radinsky in 1977. However, little work has been done on hyaenodont brains since then. The second aim of this study, therefore, was to place these hyaenodont brains, and particularly that of A. leakeyi, in the most recent phylogenetic framework, to better understand how the brain evolved in this group. This suggests that the evolution of a larger, more convoluted neocortex occurred convergently in several clades of Hyaenodonta. Furthermore, the presence of only a single neocortical sulcus in the earliest hyaenodonts calls into question the previous hypothesis of an ancestral pattern with two sulci for Artiodactyla, Perissodactyla and Carnivora. This study provides a basis for future research on brain evolution in Hyaenodonta, as well as showcases the possibilities offered by 3D technology. / Hyaenodonterna var en grupp rovdjur som levde från ca 58 till 12 miljoner år sedan och som fanns på alla nordliga kontinenter samt Afrika. De varierade mycket i storlek, precis som nu levande rovdäggdjur, från ca 0.5 kg till över ett ton. Den här studien rapporterar ett nytt fynd från norra Kenya: den första skallen av Anasinopa leakeyi, en hyaenodont som levde för ungefär 17 miljoner år sedan. Skallen är tillplattad, men nästan komplett och i övrigt i relativt gott skick. Men hjälp av datortomografi och 3D-teknologi har neurokraniet, den del av skallen som omger hjärnan, kunnat byggas ihop igen och en digital avgjutning av hjärnskålen skapats. Genom att jämföra tjockleken på synnerven i förhållande till hjärnstorleken kan man få en uppfattning om hur väl utvecklad synen var hos Anasinopa. Resultaten tyder på att Anasinopa troligen hade ungefär lika bra syn som dagens varg. Genom att mäta tänderna har Anasinopas kroppsvikt kunnat uppskattas till upp till 25 kg, vilket är ungefär lika mycket som en europeisk bäver eller en manvarg. De rovdäggdjur som lever idag, och som väger lika mycket som Anasinopa, kan jaga antingen stora eller små bytesdjur. Det finns också djur i den här viktklassen, som t.ex. schakaler och lodjur, som kan skifta mellan att jaga små och stora djur, så det är möjligt att Anasinopa också kunde det. Vår kunskap om hur hjärnan såg ut hos hyaenodonter är begränsad till mindre än ett dussin exemplar. De flesta av dessa ”hjärnor” är naturliga avgjutningar i sten, som bildats när hjärnskålen fyllts med sediment för miljontals år sedan. En studie på 1970-talet jämförde flera hyaenodont-hjärnor och fann att neocortex, den del av hjärnan som hos däggdjur ansvarar för komplexa kognitiva funktioner, med tiden blev större och mer veckad hos de här djuren. Det vill säga, de tidiga hyaenodonterna hade en liten neocortex med ett enda veck, medan de som levde miljontals år senare hade en mycket större neocortex med flera veck. Sedan den studien har dock ganska lite forskning gjorts på hjärnan hos de här djuren. I den här studien jämfördes därför Anasinopas hjärna med den hos andra hyaenodonter, med hänsyn tagen till hur de olika arterna tros vara släkt med varandra, för att försöka förstå hur hjärnan utvecklades hos de här djuren. Resultaten tyder på att en större, mer veckad neocortex utvecklades parallellt i två separata grupper av hyaenodonter. Man har tidigare kunnat se att utvecklingen av fler hjärnveck skett parallellt hos, t.ex., olika grupper av hunddjur. Dock verkar inget än så länge tyda på att sådana veck lika lätt kan förloras när de väl utvecklats hos en art. Därför tyder det faktum att de första hyaenodonterna bara hade ett veck på att deras gemensamma anfader med dagens rovdjur också bara hade ett veck. Det går emot vad man tidigare trott, om att den gemensamma anfadern till hyaenodonter och nu levande rovdjur och hovdjur och hade en neocortex med två veck, som sedan bevarats hos alla dess ättlingar. Det här visar att det är mycket vi fortfarande inte vet om hjärnans utveckling. Studien visar samtidigt på möjligheterna som 3D-teknologin innebär och visar att det finns mycket kvar att lära från de fossil vi har.

xvii, 106 p. : ill., maps. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / This dissertation establishes the age, depositional environment, composition, and climatic conditions for the Cape Blanco flora. The paleotemperature estimated by the Cape Blanco flora, the Temblor flora of California, and the Seldovia flora of Alaska are then compared with sea surface temperatures estimated from oxygen isotope analysis of benthic foraminifera. The unconformity-bound shallow marine sandstone of Floras Lake includes a redeposited tuff bed which contains fossil leaves at Cape Blanco. An 40 Ar/ 39 Ar age of 18.26 ± 0.86 Ma is presented for the tuff as well as a paleomagnetic stratigraphy of the sandstone. Sedimentary structures of the tuff bed are evidence that the tuff was deposited at or just above the strand line. The depth of tuff deposition was shallower than the adjacent marine sands, and this short-lived shoaling may have been a result of increased sediment supply. The fossil flora was an oak forest with numerous species of Fagaceae. Additional components include lanceolate Salicaceae leaves, entire margined Lauraceae, fragmentary Betulaceae, and lobed Platanaceae. Coniferous debris, charcoal, Equisetales, and Typhaceae forms are also figured. Ten leaf forms could not be confidently assigned to established names but are described, figured, and called angiosperm forms 1-10. In total 44 unique forms are identified. The size and margin type of the dicot specimens are quantified, and by comparison with known modern floras, a former mean annual precipitation of 201 (+86, -61) cm and a former mean annual temperature of 18.26 ± 2.6°C are estimated. The paleotemperature of the ∼17.5 Ma Seldovia Flora and the ∼17.5 Ma Temblor Flora are estimated using the same method, establishing a ∼0.7°C per degree of latitude temperature gradient for the northern hemisphere temperate zone. The leaf based gradient is steeper than the sea surface temperature gradient, of ∼0.26°C per degree of latitude as estimated from oxygen isotopic composition of foraminifera collected from ocean sediment cores. Both fossil leaf and isotope methods suggest that the early Miocene was ∼5°C warmer than today. This thesis includes unpublished co-authored material. / Committee in charge: Gregory Retallack, Chairperson, Geological Sciences; Rebecca Dorsey, Member, Geological Sciences; Joshua Roering, Member, Geological Sciences; Barbara Roy, Outside Member, Biology