The study takes an ecomorphological approach to the reconstruction of ruminant diets using the occlusal surface of upper molars. A multivariate approach was used to characterise ruminants of different diets using traits of the exposed enamel ridges and dentine basins. The study also employed a means of control for phylogenetic non-independence, performing the analyses at each taxonomic level from infraorder to tribe. This approach allowed an assessment of the levels of convergent evolution to the same diets within separate taxonomic units. At every level of analysis, bovids of different diets were more clearly distinguishable according to their occlusal morphology than cervids. Lower taxonomic levels generally also gave better classification results than higher ones. It is concluded that ecomorphological analyses may be influenced adversely if the ecological and phylogenetic history of the sample is not considered. Bovid browsers were generally characterised by thinner enamel ridges, especially thin buccal protocone ridges (R3), wide protocones and enamel alignment related to body size. Grazer enamel is thick, long and aligned more parallel to the chewing direction. Browse dominated and mixed feeders with equal levels of browse and grass clustered with browsers. Grass dominated mixed feeders approach the morphology of, but did not cluster amongst grazers. Interspecific morphology varied less in the Cervidae. This is correlated with lower ecological and taxonomic diversity, an absence from open and arid habitats, and low hypsodonty (crown height) compared with bovids. Links between these are considered in terms of historical biogeography and morphological constraint. The ‘cusp fusion hypothesis’ is put forward to explain the failure of cervids to exploit the increasingly arid habitats of the Neogene.

An in-depth study of the kinetoplast DNA of the human-infecting parasite <I>Leishmania panamensis</I> was conducted with the following objectives: • To find out how many minicircle sequence classes are present in the kinetoplast, and the relative abundance of each class; • To use this information to develop and test a kDNA-based diagnostic test specific for this species of parasite; • To investigate whether minicircle sequence data can be meaningfully used to infer phylogenetic relationships between <I>Leishmania</I> species; • To also investigate RNA editing in this parasite and compare it with previous results in a lizard-infecting <I>Leishmania</I>. Kinetoplast DNA from <I>L. panamensis</I> was cloned and investigated in detail by restriction enzyme typing and sequence analysis, and three other species of the <I>braziliensis</I> complex of New World <I>Leishmania</I> were analysed in a similar way. It was found that the minicircle component of the kinetoplast DNA is highly complex, and is comprised of at least 35 classes of minicircle per kinetoplast, with each class having a varying level of abundance. A kDNA probe and primers specific for <I>L. panamensis</I> were designed from an abundant minicircle class, and were subsequently field-tested in Medellin, Colombia. The sequence data generated during this study was used to infer phylogenetic relationships between the species of New World <I>Leishmania</I>. A variety of different approaches were used, and the suitability of this type of sequence data for phylogenetic analysis is discussed. The sequence data was also screened for potential guide RNA genes, and a total of 26 possible genes were identified. Comparison of the maxicircle gene sequence for the ATPase subunit 6 gene between <I>L. panamensis </I> and <I>L. tarentolae</I> (lizard-infecting) together with an analysis of previous work revealed that the RNA editing process is remarkably similar between <I>Leishmania</I> species. This study extends the little known about the organisation and function of minicircle DNA in pathogenic <I>Leishmania </I>species.

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