Blow flies (Diptera: Calliphoridae) are among the most dominant and conspicuous insects in the decomposition process. They are important in forensic entomology to determine time of death and, in certain situations, cause of death or relocation of a body. Insects are now included as standard operating procedures in crime scene investigations in many countries, however, this is not standard procedure in the Caribbean area due to lack of knowledge of insects involved in cadaveric decomposition. Successful application of forensic entomology depends on solid underlying data. Our main goal is to advance the knowledge of Calliphoridae in the Caribbean to enable forensic entomology studies. We performed a mega-transect across the Caribbean and extensively collected flies attracted to rotten meat baits during five years from 2011 to 2015. Overall we collected 61,332 flies of which 34,650 were Calliphoridae. We sampled 16 of the 18 species of forensically important Caribbean Calliphoridae and three continental species. We determine the diversity and distribution of Calliphoridae in the Caribbean. We also present a thorough DNA barcode dataset, covering the geographic range of most species in the region. Finally we established phylogenetic relationships among Calliphoridae species and test biogeographical hypotheses, and patterns of diversification and endemism in the Caribbean. In sum, this is the most comprehensive study of the family Calliphoridae from the Caribbean that will open the door for future research on forensic entomology in the region.

Esta tese consta de três capítulos nos quais são abordados questões relacionadas à sistemática de Syngonanthus (Eriocaulaceae). No primeiro capítulo são apresentadas novidades taxonômicas, com descrições de novas espécies do gênero, incluindo a primeira espécie de flor exclusivamente trímera e bissexual da família. No segundo capítulo, uma análise filogenética com amostragem expandida de Syngonanthus é apresentada, para tentar elucidar questões relacionadas ao posicionamento do gênero em Paepalanthoideae; verificação e sustentação de classificações infragenéricas anteriores; e correlação de grupos bem sustentados com padrões morfológicos. O último capítulo é composto por uma revisão taxonômica de Syngonanthus sect. Carphocephalus, um dos grupos morfologicamente mais complexos no gênero. A revisão constou de um total de 13 espécies, nos quais foram propostos novos sinônimos, lectotipificações e descrição de novos táxons. / This thesis consists of three parts involving systematics of Syngonanthus (Eriocaulaceae). The chapter I consists on taxonomic novelties, with descriptions of new species, including the first species with exclusively trimerous and bisexual flowers in the family. The second chapter is the phylogenetic study of Syngonanthus with expanded sampling This study is an attempt to clarify issues related to the placement of Syngonanthus in Paepalanthoideae; to check the support and previous infrageneric classifications; and to correlate well supported groups with morphological patterns. The chapter three consists on a taxonomic revision of Syngonanthus sect. Carphocephalus, one of the most complex groups in the genus. The revision consisted of a total of 13 species. It has been proposed new synonyms, lectotypifications and description of new taxa.

A character data set suitable for cladistic analysis of tardigrades at the family level was developed. The data matrix consisted of 50 morphological characters from 15 families of tardigrades and was analyzed by maximum parsimony. Kinorhynchs, loriciferans and gastrotrichs were used as outgroups. The results agree with the currently accepted hypothesis that Eutardigrada and Heterotardigrada are distinct monophyletic groups. Among the eutardigrades, Eoyhypsibiidae was found to be a sister group to Macrobiotidae + Hypsibiidae, while Milnesiidae was the basal eutardigrade family. The basal heterotardigrade family was found to be Oreellidae. Echiniscoideans grouped with some traditional Arthrotardigrada (Renaudarctidae, Coronarctidae + Batillipedidae) suggesting that the arthrotardigrades are not monophyletic. An 18S rRNA phylogenetic hypothesis was developed and supports the monophyly of Heterotardigrada and of Parachela versus Apochela within the Eutardigrada. Mapping of habitat preference suggest that terrestrial tardigrades are the ancestral state. Molecular analysis of a sediment sample with an unusually large population of tardigrades had a higher diversity when compared to manual sorting and counting.

Pouca atenção tem sido direcionada para Schinus L., gênero americano conhecido sobretudo pelas suas espécies cultivadas e invasoras. Na América do Sul Austral é o gênero da família Anacardiaceae com maior riqueza específica, constituído por cerca de 42 espécies distribuídas em ampla diversidade de habitats, principalmente os áridos ou semi-áridos, estendendo-se também às florestas nebulares dos Andes e do domínio da Mata Atlântica. A mais completa revisão do gênero foi realizada por Fred Alexander Barkley, botânico norte-americano, em 1957, que reconheceu dois subgêneros, S. subg. Schinus e S. subg. Duvaua, sendo o último subdividido em duas seções. Estudos subsequentes indicaram inconsistências morfológicas na circunscrição dessas categorias infragenéricas e a delimitação de várias espécies ainda é complicada. Até o momento, Schinus foi pouco amostrado nos estudos filogenéticos da família, uma vez que não constituía o grupo alvo desses estudos e, por isso, as hipóteses sobre a monofilia do gênero e o entendimento das relações entre suas espécies ainda é muito limitado. Nesse contexto, esta tese teve como objetivos principais testar a monofilia de Schinus e das categorias infragenéricas e investigar as relações filogenéticas no gênero. No primeiro capítulo, apresentamos a filogenia de Schinus baseada em sequências de DNA de 11 marcadores, sendo nove nucleares e dois plastidiais. A amostragem baseou-se na última revisão taxonômica do gênero e incluiu 47 táxons de Schinus, além de 48 espécimes de gêneros de Anacardiaceae proximamente relacionados a esse gênero. Foram realizadas análises filogenéticas individuais e combinadas utilizando inferências Bayesiana, máxima parcimônia e de máxima verossimilhança. Elaboramos uma matriz morfológica, incluindo caracteres vegetativos anatômicos, baseada na análise de materiais herborizados e fixados provenientes de coletas a campo estrategicamente realizadas em pontos selecionados da ampla distribuição do grupo focal, para obtenção de amostras de todos os táxons conhecidos de Schinus. A reconstrução de estados ancestrais de vários caracteres morfológicos foi realizada pelo critério de parcimômia, utilizando como base a árvore filogenética proveniente da análise combinada Bayesiana. Essa reconstrução morfológica teve como principais objetivos: 1. buscar um entendimento mais amplo sobre as relações interespecíficas em Schinus e entre gêneros proximamente relacionados, 2 identificar caracteres morfológicos e possíveis sinapormofias dos principais clados, e 3. discutir as hipóteses sobre a evolução de caracteres estruturais em Schinus. As análises filogenéticas demonstraram que Schinus é um gênero monofilético fortemente sustentado, no entanto, as categorias infragenéricas S. subg. Duvaua sect. Duvaua and S. subg. Duvaua sect. Pseudoduvaua emergiram polifiléticas, sendo homoplásticos os caracteres tradicionalmente utilizados na sua circunscrição. Os resultados evidenciaram oito principais linhagens fortemente sustentadas em Schinus, sendo que as espécies de folhas compostas (pinadas) constituem as três primeiras linhagens a divergirem, formando um grado, e as espécies de folhas simples emergem agrupadas em um grande clado bem sustentado, o qual apresenta cinco linhagens principais, também com boa sustentação. No entanto, as relações interespecíficas dentro de alguns clados permanece pouco resolvida. As reconstruções de estados ancestrais demonstram que alguns atributos morfológicos e anatômicos foliares são relevantes na caracterização e possivelmente sinapomorfias de algumas linhagens. No entanto, a maioria dos caracteres, principalmente os tradicionalmente empregados nas circunscrição de grupos em Schinus, demonstram um nível alto de homoplasia. De acordo com as novas evidências provenientes desse estudo, apresentamos no primeiro capítulo uma nova classificação seccional em Schinus, assim como chave de identificação para as oito seções, lista de espécies compondo cada seção, além de comentários taxonômicos, de distribuição geográfica e sobre ecologia. As seções propostas nesse estudo podem ser caracterizadas pela combinação de um conjunto de caracteres morfológicos associados à distribuição geográfica, uma vez que elas correspondem a linhagens alopátricas ou ecologicamente distintas. O estudo filogenético constitui a primeira fase de uma série de estudos sistemáticos que estão planejados e visam realizar o tratamento taxonômico de todas as seções de Schinus. Por isso, no segundo capítulo desta tese apresentamos a revisão taxonômica de S. sect. Myrtifolia, um clado notável de espécies de folhas simples que podem alcançar as mais elevadas altitudes dentre as espécies de Anacardiaceae (até 3900 m de altitude). Os 11 táxons que compõem essa seção são em sua maioria endêmicos das Yungas e florestas Tucumano-Bolivianas, e outras duas espécies também ocorrem em áreas de pre-Puna, Puna e nos vales secos interandinos da Argentina, Bolivia e Peru. Apesar das reconstruções morfológicas demonstrarem que a maioria dos caracteres morfológicos apresentam um elevado grau de homoplasia, o que torna difícil a diagnose dos principais clados, S. sect. Myrtifolia é a única seção que apresenta flores tetrâmeras e frutos lateralmente achatados, atributos incomuns e, portanto, aqui apontados como possíveis sinapormofias deste clado. Suas espécies foram reconhecidas anteriormente em S. subg. Duvaua sect. Pseudoduvaua, exceto por S. microphylla, a qual foi reconhecida como membro de S. subg. Duvaua sect. Duvaua. Problemas de delimitação específica existentes em S. sect. Myrtifolia têm sido negligenciados, uma vez que a maioria dos estudos taxonômicos no gênero frequentemente têm se limitado a destacar as dificuldades taxonômicas em S. subg. Duvaua sect. Duvaua. O presente estudo morfológico evidencia um número significante de problemas de circunscrição taxonômica, principalmente entre S. andina e S. myrtifolia. As análises morfológicas detalhadas de um considerável número de exsicatas mostraram quatro novas espécies, as quais são descritas neste trabalho. Apresentamos chave de identificação para as espécies, descrições morfológicas, sinonímia, tipos nomenclaturais, incluindo três lectotipificações, duas combinações novas, ilustrações, mapas de distribuição e avaliação do estado de conservação de todas as espécies. As novidades taxonômicas apresentadas aqui, referentes às espécies de S. sect. Myritfolia, representam uma tentativa de demonstrar a complexidade morfológica e evidenciar problemas de identificação de espécies levando em consideração uma amostragem grande e revisão nomenclatural cuidadosa. Dessa forma, esperamos destacar a gama de variação morfológica, principalmente entre S. andina e S. myrtifolia, táxons pouco estudados até o momento. Em suma, o estudo filogenético de Schinus, realizado pela primeira vez com uma amostragem abrangente de todas as linhagens componentes do gênero, oferece oportunidades para novos estudos taxonômicos, evolutivos e biogeográficos no gênero. Em particular, análises biogeográficas associadas à diversificação desse gênero e táxons relacionados de Anacardiaceae parecem muito promissoras para ampliar o conhecimento sobre a história das formações vegetacionais da América do Sul Austral / Schinus, a genus best known by its few cultivated and invasive species, is the largest genus of Anacardiaceae in southern South America. It is remarkably diverse compared to closely related genera, with approximately 42 species, most of which occur in several arid vegetation types and extending into Andean and Atlantic moist forests. The most comprehensive taxonomic revision of the genus dates to 1957, which recognized S. subg. Schinus and S. subg. Duvaua, the latter of which was further divided into two sections. Subsequent studies have highlighted morphological inconsistencies in this infrageneric classification, and species delimitation remains a challenge. Schinus has been poorly sampled in previous phylogenetic studies of Anacardiaceae, and thus any assumptions about its monophyly and relationships (particularly among its species and infrageneric categories) remain untested. This thesis aimed to test the monophyly of Schinus and its infrageneric circumscriptions, and also investigate the phylogenetic relationships. In the first chapter, we present the phylogenetic relationships of all Schinus species using nine nuclear and two plastid DNA sequence regions, most of them developed recently for Commiphora (Burseraceae). The maximum parsimony, maximum likelihood, and Bayesian inference included 47 taxa based on the latest taxonomic revision of the genus, and 48 specimens of Anacardiaceae genera closely related to Schinus. We also constructed a morphological dataset, including vegetative anatomical features, based on analysis of herbarium specimens and fresh material obtained through fieldwork, and compared these characters to hypotheses based on molecular evidence in order to: 1. achieve a better understanding of the relationships among its species and to related genera, 2. identify morphological characters and putative synapomorphies for major clades, and 3. discuss hypotheses regarding the evolution of structural traits in the group. Our analyses strongly support the monophyly of Schinus, but also indicate that its infrageneric groups S. subg. Duvaua sect. Duvaua and S. subg. Duvaua sect. Pseudoduvaua are polyphyletic and have been defined using homoplastic characters. The phylogenetic relationships that emerged from our analyses include eight strongly supported lineages (except for S. sect. Atlantica), in which compound-leaved taxa were the earliest diverging lineages, forming a grade of three strongly supported clades, and the largest Schinus clade consists of simple-leaved species, and has five well-supported main lineages. However the relationships among closely related species remain unclear in some clades. Ancestral state reconstructions demonstrate that some morphological and leaf-anatomical characters are valuable in characterizing some lineages, and may serve as potential synapomorphies to define these clades. By contrast, most of the traits that have traditionally been used to circumscribe groups in Schinus show high levels of homoplasy. In light of these results, we present in the first chapter a novel sectional classification of Schinus, an identification key for the sections and comments on the taxonomy, geographic distribution and ecology. The eight monophyletic sections proposed here are recognized by a combination of character states associated with geographic distribution, corresponding to lineages that are mostly allopatric or at least ecologically distinct. This study is the first phase of a long-term effort to produce systematics studies and taxonomic review for all species of Schinus. In this way, we present in the second chapter the taxonomic revision of S. sect. Myrtifolia, a remarkable simple-leaved clade in which species reach the highest elevations within Anacardiaceae (up to 3,900 m altitude). The 11 species of this section are mostly endemic of Yungas and Tucumán-Bolivian forests, and two species also occur in pre-Puna, Puna and dry inter-Andean valleys from Argentina, Bolivia and Peru. The fact that most of the morphological traits present high levels of homoplasy, the diagnosis of the main clades within Schinus is a challenge, except for S. sect. Myrtifolia whose species have tetramerous flowers and fruits laterally compressed, unusual character states that seem to be putative synapomorphies of this section. Its members were previously placed in S. subg. Duvaua sect. Pseudoduvaua, except for S. microphylla, a species recognized as belonging to S. subg. Duvaua sect. Duvaua. Delimitation issues have been neglected in species of this section, since most studies have focused on taxa belonging to S. subg. Duvaua sect. Duvaua. The present morphological study reveals a significant number of taxonomic circumscription problems, especially between S. andina and S. myrtifolia. Detailed morphological analyses of numerous exsiccatae reveals four new species which are described herein. We provide identification key, descriptions, synonyms, nomenclatural types, including three designations of lectotypes, two new combinations, illustrations, distribution maps, and comments on nomenclatural, distribution and preliminary conservation assessments of all species. The taxonomic novelties here presented in Schinus sect. Myrtifolia contribute to disentangle the complexity of the group and its misidentified species, taking into account the morphological traits of a virtually complete sampling and a careful nomenclatural revision. In this way we hope to have evaluated all range of morphological variation, especially within S. andina and S. myrtifolia, which has been overlooked until now. In summary the phylogenetic study of Schinus provided here including a much broader sampling of all lineages in the genus, offers opportunities for further taxonomic, evolutionary and biogeographical studies in Schinus. The biogeographical investigations associated with the diversification of Schinus and closely related taxa from Anacardiaceae seem to be promising and may contribute to new insights into the history of southern South American biota

E. coli is the most frequently isolated Gram negative pathogen from bacteremia in cancer patients and is repeatedly recovered from many other extraintestinal illnesses. These infections are commonly endogenous in nature and interfere with the treatment of cancer resulting in increased healthcare costs, morbidity, and mortality rates. Cancer and the treatments related to cancer cause alterations in the microbiome of the gut and other organs. Despite this point, there is a serious lack of knowledge about the genetic types of E. coli infecting cancer patients. This gap results in vague prevention strategies and limited treatment options for cancer patients. Multi Locus Sequence Typing (MLST) was used to successfully genotype 105 sequentially collected E. coli isolates from patients admitted to H. Lee Moffitt Cancer Center (HLMCC, Tampa, FL) with confirmed extraintestinal infections between 2010 and 2012. In total, 24 distinct genotypes (STs) have been identified in this dataset using EcMLST (STEC Reference Center). Of these, ST34 constituted 39% of the isolates and may represent a disseminating clone at HLMCC. Furthermore, 17 isolates not found in the EcMLST database have been identified. Importantly, phylogenetic analysis of DNA sequence data for MLMCC E. coli revealed only 22% of HLMCC E. coli clustered with ECOR reference strains commonly attributed to the B2 phylogroup of extraintestinal pathogenic E. coli (ExPEC). Four HLMCC E. coli belonging to ST171 and attributed to life-threatening blood infections clustered with Shiga toxin (Stx) producing E. coli (STEC) strain TW06296. HLMCC E. coli belonging to ST34 clustered with enteroaggregative E. coli (EAEC) strain TW10263. Importantly, these non-B2 phylogroup strains demonstrated more pathogenic potential than HLMCC E. coli clustered with B2 ExPEC,which included a higher incidence of bacteremia and sepsis, as well as resistance to first-line antibiotics. Upon further investigation, ST34 may equate to ST131 by another MLST database. These findings suggest that isolates previously characterized as commensal and intestinal pathogenic E. coli have an increased ability to cause infection outside of the gastrointestinal tract in cancer patients and that selective pressures are contributing to increased antibiotic resistance. These findings may change the approach to clinical management of E. coli infections at cancer centers.

Temnospondyls are large extinct fossil tetrapods; superficially resembling crocodiles in their general size, appearance and lifestyle. Temnospondyls are a group of early tetrapods, the oldest fossils are more than 340 million years old, and they existed for more than 200 million years. This doctoral thesis examined the postcranial skeleton of temnospondyls and its evolutionary history and diversification. Standard taxonomic techniques were used to distinguish between the types of variation observed in the postcranial skeleton and for phylogenetic analysis. The thesis consists of a series of published articles, three describing the postcranial skeletons of various temnospondyls, and three summary articles, all with extensive illustrations. To provide data, the postcranial skeletons of three temnospondyl taxa were described. The articulated postcranial skeleton of a basal stereospondyl (rhinesuchid) is immature, and paedomorphism of the postcranial skeleton in stereospondyls is discussed. The robust appendicular skeleton of Eryops megacephalus is plesiomorphic, well-ossified, and terrestrially adapted. The paedomorphic postcranial skeleton of Trimerorhachis insignis is plesiomorphic, and secondarily aquatic, the description includes growth stages. This study found that extensive morphogenetic variation is present in the postcranial skeleton of temnospondyls. Many phylogenetically significant characteristics develop with morphogenesis, they may be absent in early growth stages, and may never develop even in the largest growth stages of taxa with paedomorphic postcranial skeletons. Consequently, assessment of the presence or absence of a phylogenetically significant characteristic in any taxon may be dependant on the morphogenetic stage of the specimen examined. This finding has major implications for the phylogenetic analysis of temnospondyls and other early tetrapods. An overview of phylogenetic variation in the postcranial skeleton is presented, including a large phylogenetic analysis of the Temnospondyli. The most primitive temnospondyls possess fully ossified postcranial skeletons, well adapted for terrestrial locomotion, but some of the derived clades of temnospondyls have paedomorphic postcranial skeletons and are exclusively aquatic. For the first time, the postcranial skeleton of temnospondyls is comprehensively compared with that of other early tetrapods in the largest phylogenetic analysis to date, resulting in the unexpected discovery that temnospondyls are most closely related to the ancestors of amniotes. The Temnospondyli plus Neospondyli (Seymouriamorpha plus Cotylosauria plus Lepospondyli) forms a large new clade, the Terrapoda, defined by the presence of many derived synapomorphies. Some of the cranial synapomorphies of the Terrapoda are most likely related to improvements in hearing. The postcranial synapomorphies indicate that the Terrapoda are the first vertebrates to have evolved limbs that are well adapted for terrestrial locomotion. The Terrapoda are the first truly terrestrial vertebrates, their postcranial adaptations facilitated their colonisation of the land and consequent phylogenetic radiation during the early Carboniferous. Both analyses incorporate characters from previous analyses and many new postcranial characters. The results of the phylogenetic analyses are statistically more parsimonious than previous analyses and have much lower levels of homoplasy. Comparative analyses indicate that the distinctive results are most likely due to the increased use of characters pertaining to temnospondyls, increased use of postcranial characters, and differentiation between sources of morphological variation to minimise morphogenetic and phenotypic variation and elucidate true phylogenetic signal.

Since the mid 19th century, the biogeography of island South-East Asia has been the subject of much study. Early researchers explained many of the species distribution patterns by the rise and fall of sea levels and land. This and the work of other researchers culminated in a theory that emphasized the role of Pleistocene sea level low stands in species evolution. With the advent of newly developed molecular techniques, however, it became clear that many species divergence events had taken place before the Pleistocene and a biogeographical theory focusing on Pleistocene sea level changes was inadequate. In this research, I have developed a new biogeographic model that explains present-day distribution patterns and evolutionary relationships between species. I use this new model to explain 10 ‘mammalian riddles’, i.e. evolutionary or distribution patterns in selected mammal species groups that could not be explained with the existing theories. I developed the new model by analyzing the geological literature for this region, and by mapping palaeogeographical and palaeoenvironmental changes for the last 20 million years. In addition I compiled information on the palaeontological record for the region and on divergence times between taxa using a molecular clock assumption. These phylogenetic data were compared with the palaeomaps to assess whether particular divergence events could be correlated with certain palaeogeographical or palaeoenvironmental changes. The combination of these two information sources has resulted in a much-improved understanding of mammalian evolution in island SE Asia. Using this model it is now possible to relate important palaeoenvironmental events, such as the Late Miocene cooling, an Early–Middle Pliocene highstand, or the emergence and submergence of a land bridge between the Malay Peninsula and Java to evolutionary changes in species. I test the accuracy of the new model by analysing the relationships within several mammal groups using craniometric and molecular analysis. The observed relationships and deduced timing of divergence between taxa could in many cases be explained by the model, which indicates that it is relatively accurate. In addition, with the new model I have been able to find solutions to most mammalian riddles, although these results require further testing. Overall, I therefore believe I have made a significant contribution to the biogeographical understanding of island SE Asia.

The flora of New Zealand has evolved largely in the absence of terrestrial mammals, the predominant frugivore guilds being birds and reptiles. The evolution of divergent fruit traits in New Zealand may be a consequence of different selection pressure by these two guilds, and two contrasting putative dispersal syndromes have been proposed for New Zealand fleshy fruited plants. Coprosma (Rubiaceae: subtribe Coprosminae) is a speciose and morphologically diverse genus, which is distributed throughout the South Pacific and which also produces variably coloured drupes. It was selected as a model genus to investigate the evolution of fruit traits within this context. For this purpose, a molecular phylogeny for the subtribe Coprosminae and Coprosma was inferred using parsimony, likelihood and split decomposition analysis on sequences from the 16rps intron of cpDNA and ETS and ITS region of nrDNA. Up to 32 species were included in the subtribal analyses, whilst 53 species of Coprosma were used in subgeneric studies. The basis for the variety of fruit colours seen in New Zealand was determined using histology and pigment extractions. To test the assumption that fruit traits among species evolved in concert under selection from frugivore guilds, fruit shape, size and nutrient composition were determined in order to test predictions that these would co-vary with fruit colour. In the Coprosminae, fleshy drupes have arisen from dry fruited schizocarps and with two possible reversals to semi-dry drupes. Within Coprosma, fruit colour was found to be evolutionarily labile and varied both among and within lineages, particularly within two main groups where fruit colour had shifted from orange to blue and white, or red, pink and black colours respectively. The evolution of novel (non-orange) fruit colours was restricted to New Zealand, as was the small-leaved, divaricate growth form, the combination of which has been associated with a putative reptile dispersal syndrome. Several trans-oceanic dispersals out of New Zealand were also inferred from the phylogeny, these extending into Australia, New Guinea and Hawai�i. In these instances, fruit colour did not appear change markedly after establishment in a new country. Within New Zealand, fruit sizes were found to vary with colour as predicted, although the majority of species produced small (< 8 mm), elliptical fruits. There was no clear association between fruit colour and fruit nutrient composition. It would appear that these small, succulent, carbohydrate-rich and lipid-poor fruits cater to a wide range of generalist frugivores. The variety of fruit colours in Coprosma stemmed from qualitative and quantitative differences in carotenoid and anthocyanin composition. The genetic basis for the control of these pathways is currently unknown, but it is assumed that a few regulatory genes can control a substantial amount of phenotypic variation. Considering the evolutionary history of Coprosma, it would appear that a history of recent and rapid speciation, hybridisation and reticulate evolution may have increased the tempo of fruit colour evolution in the genus.

"December 2001" / Bibliography: leaves 227-246. / iv, 246 leaves : ill. ; 30 cm / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 2002

<p><i>Heterodrilus</i> is a marine group of small (3-25 mm) clitellates that occur interstitially in sandy sediments from the intertidal zone down to about 150 m depths. The taxon includes 42 valid species and has been recorded from localities in the Mediterranean Sea, the North-west Atlantic Ocean (including the Caribbean), the Galapagos Islands, and the Indo-Pacific Region. A majority of the species of <i>Heterodrilus</i> are characterized by having trifid anterior chaetae (i.e., chaetae with three teeth at the distal end). A few species have bifid chaetae, but these are regarded as having lost the third tooth secondarily. Within the taxon, species are distinguished by morphological characters in the internal organization of the male and female genitalia, but also by characters in the form and number of chaetae. In this thesis, two new taxa are introduced, <i>Heterodrilus tripartitus </i>and <i>H. ursulae</i>, both from the Mediterranean Sea. The ultrastructure of the cuticle in four species (<i>H. paucifascis, H. pentcheffi, H</i>. <i>flexuosus, H. minisetosus</i>) is studied and it is shown that there is interspecific variation in the morphology of the cuticle. One of the studied species, <i>H. paucifascis</i>, shows intraspecific variation, which is associated with sample locality. The systematic position of <i>Heterodrilus</i> within Tubificidae is studied with molecular markers, and the results support that <i>Heterodrilus </i>(earlier classified as a member of Rhyacodrilinae) is positioned within Phallodrilinae. Furthermore, the phylogenetic relationships within <i>Heterodrilus</i> are estimated based on molecular characters from mitochondrial COI, the 16S rRNA gene, and the nuclear 18S rRNA gene, and the result indicate that the two major clades in our tree corresponds to different geographical distributions. This thesis also includes a checklist, as well as a key, to the species of <i>Heterodrilus</i>.</p>