No description available.

No description available.

This project seeks to explore, name, and describe some of the earliest known members of Alligatoroidea. Explorations of Bottosaurus harlani and Deinosuchus reveal that early in their evolutionary history alligatoroids had attained bauplans that are highly divergent from the ancestral condition in both body size and morphology. Bottosaurus harlani preserves aspects of the skull table – including constricted supratemporal fenestrae, a linear frontoparietal suture, and a large trapezoidal dorsal supraoccipital exposure – that are similar to those of caimans. Optimal trees from phylogenetic analysis recover B. harlani in three different positions; as a sister either to the modern dwarf caimans (Paleosuchus), or either living species of Paleosuchus. That a substantial stratigraphic gap separates B. harlani from both species of Paleosuchus, which first appears in the Miocene, along with low character and nodal support raises questions about this relationship. However, should the relationships recovered here be true, Bottosaurus harlani would be the oldest known caiman. The taxon indicates that morphologies common to modern caimans date to the earliest record of the clade. In addition to the enigmatic B. harlani, the Campanian giant Deinosuchus was re-evaluated as part of this project. Recent consensus has been that the three named species of Deinosuchus (D. hatcheri, D. riograndensis, and D. rugosus) represent a single, widely ranging species. Newly-collected material from the Big Bend region of western Texas and increased sampling of the lineage from throughout North America allowed for a review of species-level systematics of Deinosuchus and helped refine its phylogenetic placement among crocodylians. Deinosuchus from western and eastern North America can be consistently differentiated and represent different species. As a result of the lack of diagnostic characters in the very incomplete holotype specimen, the name Deinosuchus is restricted to D. hatcheri. To encompass specimens formerly included in Deinosuchus a new genus, Deinosuchoides, is erected. In addition to naming a new genus, the holotype specimen for Deinosuchus rugosus is determined to be undiagnostic to species level and is therefore a nomen dubium. A new species, Deinosuchoides schwimmeri, is erected upon a cranial specimen from Mississippi. The snout of Deinosuchoides is very long and wide. Almost invariably, crocodylian snouts are either long or wide, but not both. In addition to the unusually long and wide snout, the skull table of this taxon bears hallmarks found in species of other long-snouted taxa such as Tomistoma and Gavialis. To explore the variability of the crocodylian skull table a morphometric analysis was conducted with the inclusion of fossil taxa. As the skull table is robust and likely to be recovered in the paleontological record this element was an ideal fit for a morphometric study. In addition to establishing the morphospace occupation of fossil taxa, the morphometric analysis found considerable overlap in morphospace between Alligatoroidea and Crocodyloidea – the overlap between these groups may be the product of shared ancestry. Additionally, similarities exist in the ecologies of these groups as evidenced by shared snout shape categories. This project finds association between skull table shape and snout length. As such, plotting isolated skull tables in morphospace, may indicate snout length and thus ecology of fossil taxa. When landmarks representing the supratemporal fenestrae are included in the analysis Gavialoidea is broadly separated from the other groups in morphospace. It has been long hypothesized that the size of the supratemporal fenestrae reflect the length of the snout as a result of jaw musculature attaching to their medial margins. However, this relationship is not as straightforward as previously hypothesized; the snouts of the crocodyloids Tomistoma and Euthecodon may exceed the length of the snout in gavialoids but their supratemporal fenestrae are proportionally smaller. This study suggests that a phylogenetic constraint on the size of the supratemporal fenestrae may be present in crocodyloids. In addition to exploring morphospace occupation, allometric trajectories of all extant taxa with available ontogenetic sequences were explored. The smallest extant taxa (O. tetraspis, P. palpebrosus, and P. trigonatus) demonstrate allometric trajectories that plot alongside the juveniles of the other taxa in this analysis. This may suggest that the small sizes of the skull tables in these species were achieved through paedomorphosis, or the maintenance of juvenile morphologies into adulthood.

Goniopholididae is a distinctive and common clade of crocodyliforms known from the Jurasic and Cretaceous of Europe, Asia, and North America. Their position within Neosuchia makes them makes them very important to the study of crocodyliform evolution, but unfortunately their phylogenetic status is ambiguous. This study describes the osteology of two North American fossil taxa: Amphicotylus stovalli, a previously under-represented goniopholidid from the Jurassic Morrison Formation of Oklahoma, and new material of Denazinosuchus kirtlandicus from the Cretaceous Kirtland Formation of New Mexico. A phylogenetic dataset is then constructed including a full sampling of Jurassic North American forms and incorporating new new goniopholidid taxa not previously treated in a phylogenetic context. The affinity of North American and European members of Goniopholis is assessed as are the taxonomic status of putitive goniopholidids Vetisuchus and Denazinosuchus. Goniopholididae is monophyletic, and North American goniopholidids form a nested clade united by a distinctive palate morphology. Furthermore, all Morrison Formation goniopholidids are further nested in the North American clade. North American "Goniopholis" are generically distinct from European forms, and should be ascribed to Amphicotylus. Amphicotylus gilmorei is a junior synonym of A. lucasii. Denazinosuchus and Vectisuchus are not constituents of Goniopholididae, and instead are more closely related to pholidosaurs and thalattosuchians.

Cerebral aneurysm rupture is a major cause of death and permanent disability. Rupture rate, however, is low; therefore, a physician must weigh the risk of rupture against treatment risk. In order to help physicians determine the rupture risk of any particular case, studies have previously explored morphology as an indicator for mechanical and hemodynamic characteristics of rupture-prone aneurysms. Morphological characteristics of the aneurysms in these studies are often quantified with morphometric indices, or normalized measures of specific geometric traits. This study introduces several novel morphometric indices. These include tissue stretch ratio, which characterizes the amount of deformation which aneurysm tissue may have undergone; neck-to-vessel ratio, which may have hemodynamic implications and is derived from the ratio of the diameter of the ostium to the diameter of the parent vessel; ellipticity index, which may indicate increased wall tension due to an elliptical shape; and non-sphericity index, which may indicate the presence of stress concentrations due to a non-spherical shape. In order to extrapolate these morphological measures, the aneurysm must first be separated from the parent vasculature. A novel method for aneurysm sac isolation is presented, which uses an approximation of the healthy parent vessel to remove all non-aneurysmal portions of a vascular model. This approach results in a more complete extraction of the aneurysm geometry than is possible using previous standard techniques. The repeatability of the isolation process is analyzed, as well as mesh-independence and the agreement of the resulting aneurysm sac model to a known geometry.

No description available.

No description available.

Note: In the print original, page 38 appears to be missing, and there are two different page 272s.

The terrestrial orchid Thelymitra matthewsii Cheeseman, uncommon in New Zealand, was studied to increase knowledge of the species life cycle, morphology and ecology. Results will enhance future conservation management for the species. New information related to the morphology of T. matthewsii was obtained. The species was found to emerge in one of four discrete life stages of distinctive morphology and height range that remained constant for the season, not developing into a more advanced life stage. The leaf of the three pre adult life stages designated a hook, a spiral, and a non flowering stage, did not inflate at the base, but rose smoothly from the tuber. Apparent morphological differences in the column between descriptions of the Australian taxon and the small New Zealand sample examined suggested further study was needed. Comprehensive monthly monitoring was carried out at five study sites in three locations in the Te Paki area of the Far North, from 2002 to 2004. No patterns emerged in plant life stage succession, flowering, and presence or absence at labels reinforcing the concept that variability was a common component of the population census. Seasonal and partial absence was a major component of the populations. An average of 32.8% of plants, over five study sites, were present throughout three seasons, while 66.9% were recorded as absent (not visible) at monitoring. New plants appearing in 2003 and 2004 showed a high percentage of subsequent absence (mean 85.7%). To determine population stability, recruitment and absence were compared. Plant absence exceeded recruitment by 7% (mean plant absence 30.5%; mean recruitment 23.4%). Plants continued to appear during the monitoring period, and labeled plants increased two-fold over commencement numbers. Adults recorded as 28% of labeled plants over three seasons, were out numbered by pre-flowering stages. Only 5% of population numbers exhibited succession from a smaller to a flowering plant. Life stage modeling indicated a life stage was more likely to be followed by the same stage than an expected successive stage. Thelymitra matthewsii was found to be present in four substrates in the Far North. The survey of vegetation found the indigenous species Kunzea ericoides and the exotic Hakea gibbosa dominant for both height, and cover. Litter and bare ground dominated ground cover. Differences in vegetation and ground cover, of sites supporting T. matthewsii and comparison sites that did not, were minor and suggested that another factor, for example a suitable fungal partner, influenced the species presence or absence. The results of the study indicated the present threat classification of Thelymitra matthewsii is inadequate in the light of the species relatively circumscribed, widely separated habitats, the small number of reproducing individuals and vulnerability to habitat modification.

Ngalakgan is an Australian language of the Gunwinyguan family, spoken fluently by just a few people in the mid Roper River area of the Top End. The thesis is a description and examination of the phonology, prosody, and morphology of Ngalakgan, based on several years of fieldwork. Ngalakgan is a language with a rich inventory of classically Gunwinyguan morphological features, including noun class agreement for all major and some minor word classes, compounding of both nouns and verbs, and a rich array of modifying and inflectional prefixes and suffixes. In Ngalakgan, there is a distinction between two kinds or 'levels' of morphology: 'root'-level and 'word'-level. Root-level morphology is lexicalised and unproductive. It is restricted to the tense/aspect/mood inflection of the small closed class of 'finite' verb roots, and to the large closed class of compounds of these roots. Word-level morphology is productive, and includes almost all prefixes, all (non-tensed) suffixes and all clitics. Only word-level structure is consistently reflected in prosodic structure; forms which are complex only at the root-level are treated as prosodic units. I show that all word-level morphemes constitute prosodic domains: every word-level stem, affix and clitic potentially begins a new domain for metrical foot structure. Geminates and glottal stops are over-represented at morpheme boundaries in complex words. In addition, they are subject to complex, non-local alternations with simple stops and zero, respectively, in Ngalakgan and related languages. The alternations are conditioned by preceding geminates and voiceless obstruent clusters, as well as by prosodic and morphological structure. I propose that voiceless obstruent clusters constitute 'boundary signals' to morphological structure, in a similar fashion to stress and, like stress, are 'licensed' by the organisation of intonation. Ngalakgan displays a quantitive-sensitive stress system in roots which is apparently unique to languages of this area. Heavy syllables in Ngalakgan are those which are articulatorily and perceptually complex: those in which the coda is followed by a consonant with a distinct place of articulation. Geminates, homorganic nasal+stop clusters and glottal stops interact with this distinction in ways which are not predicted by current prosodic theories.