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Item The evolution of reproduction within Testudinata as evidenced by the fossil record(Montana State University - Bozeman, College of Letters & Science, 2017) Lawver, Daniel Ryan; Chairperson, Graduate Committee: Frankie Jackson; David Varricchio (co-chair); Frankie D. Jackson was a co-author of the article, 'A review of the fossil record of turtle reprodution: eggs, embryos, nests, and copulating pairs' in the journal 'Bulletin of the Peabody Museum of Natural History' which is contained within this thesis.; Armand H. Rasoamiaramanana and Ingmar Werneburg were co-authors of the article, 'An occurrence of fossil eggs from the Mesozoic of Madagascar and a detailed observation of eggshell microstructure' in the journal 'Journal of vertebrate paleontology' which is contained within this thesis.; Frankie D. Jackson was a co-author of the article, 'An accumulation of turtle eggs with embryos from the Campanian (upper Cretaceous) Judith River Formation of Montana' in the journal 'Cretaceous research' which is contained within this thesis.; Frankie D. Jackson was a co-author of the article, 'A fossil egg clutch from the stem turtle Meiolania platyceps: implications for the evolution of turtle reproductive biology' in the journal 'Journal of vertebrate paleontology' which is contained within this thesis.Although known from every continent except Antarctica and having a fossil record ranging from the Middle Jurassic to the Pleistocene, fossil turtle eggs are relatively understudied. In this dissertation I describe four fossil specimens, interpret paleoecology and conduct cladistic analyses in order to investigate the evolution of turtle reproduction. Fossil eggshell descriptions primarily involve analysis by scanning electron and polarized light microscopy, as well as cathodoluminescence to determine the degree of diagenetic alteration. Carapace lengths and gas conductance are estimated in order to investigate the ecology of the adults that produced fossil turtle eggs and clutches, as well as their incubation environments, respectively. Cladistic analyses of turtle egg and reproductive characters permit assessment of the usefulness of these characters for determining phylogenetic relationships of fossil specimens and the evolution of reproduction in turtles. Specimens described here include 1) Testudoolithus oosp. from the Late Cretaceous of Madagascar, 2) a clutch of eggs (some containing late stage embryos and at least one exhibiting multilayer eggshell) from the Late Cretaceous Judith River Formation of Montana and named Testudoolithus zelenitskyae oosp. nov., 3) an egg contained within an adult Basilemys nobilis from the Late Cretaceous Kaiparowits Formation of Utah, and 4) a clutch of Meiolania platyceps eggs from the Pleistocene of Lord Howe Island, Australia. Meiolania platyceps eggs are named Testudoolithus lordhowensis oosp. nov. and provide valuable information on the origin of aragonite eggshell composition and nesting behaviors. Cladistic analyses utilizing egg and reproductive characters are rarely performed on taxa outside of Dinosauria. My analyses demonstrate that morphological data produces poorly resolved trees in which only the clades Adocia and Trionychia are resolved and all other turtles form a large polytomy. However, when combined with molecular data, egg and reproductive characters have more resolving potential towards the top of trees. This poor resolution is likely due to homoplasy in the form of character reversals, convergent evolution, and/or from the limited number of informative characters.Item Paleoenvironment and taphonomy of the fauna of the Tullock Formation (early Paleocene), McGuire Creek area, McCone County, Montana(Montana State University - Bozeman, College of Letters & Science, 1992) Katsura, YoshihiroItem Fossil eggs and perinatal remains from the upper Cretaceous Two Medicine Formation of Montana : description and implications(Montana State University - Bozeman, College of Letters & Science, 2014) Oser, Sara Elizabeth; Co-chairpersons, Graduate Committee: Frankie Jackson and David Varricchio; Frankie D. Jackson was a co-author of the article, 'Sediment and eggshell interactions: using abrasion to assess transport in fossil eggshell accumulations' in the journal 'Historical biology' which is contained within this thesis.Egg Mountain is a dinosaur nesting site located in the Upper Cretaceous, Two Medicine Formation of western Montana. The site was located on a coastal plain with seasonal variations in rainfall and was utilized as a nesting location by several taxa. Egg Mountain hosts a remarkable diversity of fossil eggshell and is a window into the reproductive behavior of multiple extinct taxa. A recent 4x6 m excavation revealed two clusters of unidentified eggs, 185 Spheroolithus eggshell fragments, and perinatal osteological remains within homogenous siliciclastic mudstone. Insect burrows (Celliforma) and cocoons (Rebuffoichnus) were excavated from the micritic limestone bed capping the excavation. The objectives of this thesis are to 1) describe the eggs and eggshell fragments, 2) determine nesting environment, 3) assign the osteological remains to taxon, and 4) investigate the taphonomic history of the site. Analytical methods include scanning electron microscopy, cathodoluminescence, petrographic microscopy, and ImageJ photo analysis. The lithologically compressed, unidentified 12 cm diameter eggs occur in two clusters containing 7-22 eggs. Diagenetic alteration obscures eggshell microstructure, inhibiting ootaxonomic assignment of the 0.5 mm thick eggshell. The 0.8-1.3 mm thick fragmentary eggshell is assigned to Spheroolithus albertensis based on microstructure, sagenotuberculate ornamentation, and prolatocanaliculate/ rimocanaliculate pores. To assess taphonomic history of the Spheroolithus fragments, chicken (Gallus gallus domesticus) and ostrich (Struthio camelus) eggshells were placed in a tumbler with water and quartz sand to simulate transport. The resulting wear on these fragments was compared to unabraded eggshell. In addition, modern eggshell was compared to fossil eggshells from a fossil nesting site, crevasse splay and channel deposits, and Egg Mountain. Spheroolithus eggshell from Egg Mountain lack edge rounding and resemble fossil eggshell from a nesting site and unabraded modern eggshell, suggesting a parautochthonous assemblage. Spheroolithus and unidentified eggs from cluster 1 respectively have gas conductance values 16-32x and 4-13x higher than avian eggs of the same mass, suggesting enclosed nest environments. The morphology of the humerus and skull elements of the perinatal osteological remains is consistent with the Hadrosauridae, though the juvenile status and incomplete nature of the specimen inhibits further taxonomic assignment.Item Scratch-digging in the Cretaceous basal ornithopod dinosaur Oryctodromeus cubicularis : evidence from morphometric analyses and reconstruction of the forelimb musculature(Montana State University - Bozeman, College of Letters & Science, 2013) Fearon, Jamie Lynn; Chairperson, Graduate Committee: David Varricchio; David J. Varricchio was a co-author of the article, 'Morphometric analysis of the forelimb and pectoral girdle of the Cretaceous ornithopod dinosaur Oryctodromeus cubicularis and implications for digging' submitted to the journal 'Journal of vertebrate paleontology' which is contained within this thesis.; David J. Varricchio was a co-author of the article, 'Reconstruction of the forelimb musculature of the Cretaceous ornithopod dinosaur Oryctodromeus cubicularis: implications for digging' submitted to the journal 'Journal of vertebrate paleontology' which is contained within this thesis.The basal ornithopod dinosaur Oryctodromeus cubicularis was discovered within a burrow structure in the mid-Cretaceous Blackleaf Formation of western Montana. This, and features of the pelvis, skull, and forelimbs also seen in burrowing mammals led to the interpretation of Oryctodromeus as the first formally described burrowing dinosaur. This study further describes the forelimb specialization of Oryctodromeus and analyzes the validity of the interpretation of Oryctodromeus as adapted for digging using morphometric analyses and muscular reconstructions of the humerus, scapula, and coracoid. The morphometric analyses used two methods, including traditional morphometrics using principal component analysis of a series of element length measurements and geometric morphometrics using relative warp analysis of a series of landmarks superimposed on photographs of elements. Both methods reduce the number of variables to explain the greatest amount of variation between specimens. Results indicated that the humerus of Oryctodromeus is slightly more robust than other basal ornithopods, the coracoid exhibits no specialization for digging, and the scapula is strongly specialized, with a long narrow acromion and strongly expanded posteroventral margin of the scapular blade providing greater surface area for muscle attachment. Reconstruction of the forelimb musculature was generated by comparing both the presence or absence of muscles and the locations of attachment sites between birds and crocodilians, the extant phylogenetic bracket of dinosaur, and by examination of specimens of Oryctodromeus and other ornithopods for osteological correlates. Muscle groups used for burrowing in mammals include the deltoideus scapularis, latissimus dorsi, triceps longus, and teres major. The first three are present in Oryctodromeus, but the presence of the teres major is equivocal. The strongly expanded posteroventral scapula indicates an increased surface area for the origin of the deltoideus scapularis and possibly teres major. This expanded area would be advantageous for burrowing. The origin of the triceps longus near the glenoid of the scapula would not provide strong extension of the antebrachium, a motion important in scratch-digging. The osteology and musculature both provide evidence of slight adaptation for scratch-digging in Oryctodromeus. As many vertebrates burrow without morphological specializations, the presence of these features sufficiently supports adaptation for burrowing in Oryctodromeus.Item Taphonomic and biostratigraphic analysis of fossil freshwater turtles in the upper Cretaceous (Campanian) Kaiparowits Formation of southern Utah, USA(Montana State University - Bozeman, College of Letters & Science, 2012) Knell, Michael Jo; Chairperson, Graduate Committee: David Varricchio; Frankie Jackson, Alan Titus and L. Barry Albright III were co-authors of the article, 'A gravid fossil turtle from the upper Cretaceous (Campanian) Kaiparowits Formation, southern Utah' in the journal 'Historical biology' which is contained within this thesis.Freshwater turtles comprise a large percentage of many fossil vertebrate assemblages in western North America. The Upper Cretaceous (Campanian) Kaiparowits Formation, a thick sedimentary unit composed primarily of fluvial and floodplain deposits, is well-exposed within Grand Staircase-Escalante National Monument in southern Utah and is known for abundant fossil turtle remains. The abundance of fossil turtles may be attributed to a variety of factors including high preservation potential. The purpose if this project is to analyze the preservation potential of freshwater turtles, particularly in fluvial depositional environments, by examining the morphology of turtles in relation to transportability and the environment of deposition. It is hypothesized, for instance, that turtles with large, robust shells that were deposited in locations offering rapid burial had a greater preservation potential than those with more fragile shells and those that were exposed for longer periods of time prior to burial. Taphonomic data, including preservation quality, taxon identification, and sedimentary context, was collected for over 700 turtle specimens in both museum collections and in the field. Depositional environment was inferred for specimens with sedimentary context data. A comparison of taphonomic data shows a preservation preference towards turtles that were buried within channel deposits, but only for those with robust shells. Remains of larger turtles are common, but typically only as fragmentary remains. Small turtle taxa are all found as fragments, primarily in overbank, pond, and other floodplain deposits. An analysis of transport and deposition trends was conducted by comparing the orientation and alignment data from in situ fossil specimens to the results of a flume study using the shells from a variety of extant taxa. Results show that shells with a more highly domed carapace tend to be deposited in a carapace-up orientation. There is also a trend for oblong shells to align themselves lateral-to-flow in the channel prior to burial. Examination of alignment trends supports previous paleoflow direction estimates using sedimentary structures. An analysis of the biostratigraphic distribution of the various turtle taxa within the Kaiparowits Formation reveals no apparent change in turtle fauna during deposition of the formation.Item Postglacial vegetation, fire, and climate history of Blacktail Pond, Northern Yellowstone National Park, WY(Montana State University - Bozeman, College of Letters & Science, 2008) Huerta, Mariana Angelica; Chairperson, Graduate Committee: Cathy WhitlockPrevious studies in Yellowstone National Park (YNP) suggest intensification of the summer-dry and summer-wet patterns in Yellowstone during the early Holocene when increased summer insolation caused atmospheric circulation patterns to strengthen. To examine this hypothesis further, pollen and high-resolution charcoal records were analyzed from Blacktail Pond to reconstruct fire and vegetation histories near the present transition between summer-wet and summer-dry conditions. The site currently lies in Pseudotsuga parkland with Artemisia steppe at lower elevations around the pond. The site supported sparse tundra prior to 12,000 cal yr B.P. and fires were uncommon. Between 12,000 and 11,000 cal yr B.P, fire activity increased and Picea-Pinus parkland was established. These changes are consistent with increasing temperature and moisture. Between 11,000 and 7600 cal yr B.P., pollen evidence of a Pinus-Picea-Abies forest is consistent with increased winter moisture, while high fire activity at this time indicates that summers had lower effective moisture than at present. Between 7600 and 4000 cal yr B.P., vegetation around the site shifted to parkland dominated by Pinus, Picea, Pseudotsuga, and Artemisia indicating that effective winter moisture decreased. Fire activity continued to be high during this time suggesting summers maintained low effective moisture. The development of Artemisia steppe around the site over the last 4000 years indicates that effective winter moisture decreased, while decreased fire activity indicates that effective summer moisture increased during this time. Winter conditions during the early Holocene that resemble a summer-wet site along with summer conditions at the same time resembling a summer-dry site could be a result of the geographical setting of Blacktail Pond near the boundary between these two precipitation regimes. Poaceae/Artemisia pollen ratios were used to infer wet/dry climate oscillations during the late Holocene. The fluctuations correspond well with other paleoclimate data from northern Yellowstone National Park (Gennett and Baker, 1986; Hadly, 1996; Meyer et al., 1995), and suggest that conditions were drier from 3775-3125, 2475-2225, 1700- 675, and 425-75 cal yr B.P.Item A 20,000-yr-old record of vegetation and climate from Lower Red Rock Lake, Centennial Valley, Southwestern Montana(Montana State University - Bozeman, College of Letters & Science, 2010) Mumma, Stephanie Ann; Chairperson, Graduate Committee: Cathy WhitlockA ca. 20,000-yr-old sediment core from Lower Red Rock Lake (LRRL) in the Centennial Valley of southwest Montana was obtained to reconstruct the vegetation, climate, and environmental changes during and following the late-Pinedale Glaciation in the northern Rocky Mountains. The base of core LRRL 06P49 consisted of inorganic silt and clay, deposited when a large glacial lake occupied the eastern Centennial Valley. The glacial lake receded during the late-glacial period when its western outlet stabilized. Prior to 17,000 cal yr BP, high pollen percentages of Juniperus, Poaceae, Asteraceae, and other herbs as well as low pollen accumulation rates suggest cold dry conditions. The sparsely vegetated landscape at LRRL is consistent with paleoclimate model simulations that show southward displacement of the jet stream and a strong glacial anticyclone during the full-glacial period. Between 17,000 and 10,500 cal yr BP, increases in Picea and Abies pollen percentages suggest a shift to subalpine parkland and warmer conditions than before as result of the northward shift of the jet stream and increasing summer insolation. From 10,500 to 7100 cal yr BP, pollen percentages of Picea and Abies decreased and those of xerophytic taxa (e.g., Chenopodiaceae and Pseudotsuga) increased, suggesting development of steppe and open forest. Warmer drier conditions in the early Holocene were likely a response to increased summer insolation and a strengthened Pacific subtropical high-pressure system. From 7100 to 2400 cal yr BP, cooler and moister conditions at LRRL, driven by decreasing summer insolation, led to the expansion of high-elevation conifers, steppe, and wetlands. Increases in Picea and Abies pollen percentages after 2400 cal yr BP indicate further closing of forests at high elevations and even cooler and wetter conditions than before. Examination of the first arrival of Pseudotsuga in pollen records throughout the region shows that its arrival was later at sites on the Atlantic side of the Continental Divide as compared to sites on the Pacific side. The geographic pattern suggests that the Continental Divide posed a topographic or climate barrier in the late-glacial period, delaying the migration of Pseudotsuga menziesii from glacial refugia.Item Incubation of Continuoolithus canadensis eggs from the late Cretaceous Two Medicine Formation of Montana(Montana State University - Bozeman, College of Letters & Science, 2012) Schaff, Rebecca Joy; Chairperson, Graduate Committee: Frankie JacksonIncubation strategies of extinct organisms are largely speculative. Most inferences of nesting behavior are based on comparison with closely related extant taxa. To date the most useful evidence for support of a particular incubation strategy includes water vapor conductance (determined from fossil eggshell) and sedimentary structures, associated with eggs or eggshell, that are interpreted as fossil nests. One such sedimentary structure (MOR 3062) from the Upper Cretaceous Two Medicine Formation of Montana, is described along with the microstructure of the associated eggs and eggshell (oospecies Continuoolithus canadensis). The green nest trace truncates red mudstone and differs in sedimentary attributes. Geochemical analysis indicates that the host substrate was highly oxidized compared to the in-filled nesting structure. This is probably due to presence of decaying vegetative debris within the structure. A Continuoolithus canadensis egg removed from MOR 3062, along with Continuoolithus canadensis eggs from the nearby site TM-006, have a water vapor conductance value of 119 mgH ²O/ (day Torr). This equates to a 4.1 times greater mean water vapor conductance in Continuoolithus canadensis than a bird egg of the same mass. American alligator (Alligator mississippensis) eggs have a water vapor conductance rate 4.2 times greater than a bird egg of the same mass. Strong similarities exist between relative water vapor conductance of Continuoolithus canadensis and modern alligators. In addition, characteristics of MOR 3062 suggest the eggs were buried in a mixture of sediment and vegetative debris: therefore, I conclude that Continuoolithus Canadensis eggs were incubated underground, possibly with the aid of heat produced by rotting vegetation.Item Multivariate analysis of avian and non-avian theropod pedal phalanges(Montana State University - Bozeman, College of Letters & Science, 2008) Kambic, Robert Emmett; Chairperson, Graduate Committee: David VarricchioThe relationship between morphology and behavior in theropods was examined using multivariate analyses performed on a set of linear measurements of pedal non-ungual phalanges in a sample of 132 extant and 13 extinct taxa. Principal component analysis reveals that modern birds with terrestrial lifestyles tend to cluster away from those with raptorial and non-predatory grasping lifestyles although the division is not clean. Most non-avian dinosaurs tend to cluster with terrestrial species although Deinonychus and some Tyrannosaurids cluster with raptorial taxa. Terrestrial taxa tend to have phalanges that are comparatively shorter distally, are relatively wide, and have shallow grooving of the distal trochleae, while grasping taxa show opposing trends. Predatory graspers have proportionately wider phalanges than non-predatory graspers. Discriminant function analysis performs well in distinguishing among species with specialized behavior while taxa with less stereotyped behaviors are harder to classify. Predatory graspers are easily separated from non-predatory graspers. Troodon and Elmisaurus are grouped with terrestrial/cursorial taxa. Tyrannosaurus, Allosaurus, Daspletosaurus, and Albertosaurus are identified as terrestrial/cursorial with some possible predatory grasping ability. Deinonychus and Bambiraptor appear to have more grasping ability than Troodon.Item Titanosaur reproductive biology : comparison of the Auca Mahuevo Titanosaur nesting locality (Argentina), to the Pinyes Megaloolithus nesting locality (Spain)(Montana State University - Bozeman, College of Letters & Science, 2007) Jackson, Frances Drew; Chairperson, Graduate Committee: David VarricchioTaphonomic and microstructural studies at the Late Cretaceous Auca Mahuevo titanosaur nesting site (Argentina) reveal significant differences in reproductive attributes compared to alleged sauropods producing Megaloolithus eggs at the Pinyes locality (Spain). Auca Mahuevo clutches contain 15-40 M. patagonicus eggs; many of the 12-14 cm eggs contain titanosaur remains. Six clutches include both normal and abnormal eggs exhibiting three types of abnormal morphology: Type I displays two normal, superimposed eggshells, while Type II and III exhibit a normal inner eggshell, with one and three overlying eggshells, respectively. Previous studies that endeavor to link egg abnormalities to dinosaur extinction lack taphonomic and rigorous statistical methods. The Pinyes locality occurs in the Tremp Formation, exposed in the Spanish Pyrenees. The overbank deposits contain clutches with 4-12 eggs; none of the 16-24 cm M. Siruguei eggs contain embryos. Although often assigned to sauropod dinosaurs, M. siruguei differs from M. patagonicus in clutch size, egg volume, shell thickness, pore density, and incubation mode; thus, taxonomic assignment to sauropods seems questionable.