Com 23-24 espécies viventes, a diversidade atual de crocodilianos é irrisória quando comparada ao registro fóssil do grupo, principalmente se considerados todos os representantes de Crocodyliformes. À luz desta grande diversidade, este trabalho visou contribuir para o melhor entendimento da complexa história evolutiva dos crocodiliformes. Deste modo, são apresentados aqui, em duas partes distintas, os resultados obtidos durante o mestrado, que focou no estudo de dois Crocodyliformes fósseis. Na primeira parte, é descrita uma nova espécie de Baurusuchidae (Mesoeucrocodylia), baseada em um esqueleto completo coletado em General Salgado-SP (Formação Adamantina, Cretáceo Superior). Nomeado Aplestosuchus sordidus, o novo táxon foi incluído em uma análise filogenética no contexto dos Baurusuchidae, sendo posicionado em Baurusuchinae, como grupo-irmão com Baurusuchus albertoi. Além disso, na cavidade abdominal deste espécime, restos de outro indivíduo, associado a Sphagesauridae, foram preservados, revelando o primeiro registro inequívoco de conteúdos abdominais para Crocodyliformes fósseis. Assim, também é discutida a estrutura trófica do ambiente daquela época, amplamente dominada por crocodiliformes. Já a segunda parte envolveu a redescrição anatômica de Eocaiman cavernensis (Crocodylia, Caimaninae) do Eoceno Médio da Argentina. Esta importante espécie é presença constante em estudos filogenéticos sobre Caimaninae, sendo que a reavaliação de sua osteologia visou gerar novas informações anatômicas. Tais dados foram incorporados numa análise filogenética, no intuito de testar sua influência sobre a filogenia dos Caimaninae e demais Crocodylia. Adicionalmente, também foram desenvolvidas discussões acerca da paleobiogeografia e paleoecologia do gênero Eocaiman no contexto dos Caimaninae. / Crocodyliformes were much more diverse in the past than today. This incredible diversity is translated into a wide range of ecological niches occupied by these animals, many of which differ from the typical semiaquatic habit of the extant forms. In this context, the project developed during the MSc degree aimed to increase the knowledge about Crocodyliformes, with the study two fossil taxa, presented here in two separated parts. The first part includes the description of Aplestosuchus sordidus, a new species of Baurusuchidae (Mesoeucrocodylia), based on a nearly complete skeleton collected in deposits of the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). A phylogenetic analysis was performed to investigate the affinities of the new taxon, suggesting its sister-taxon relation to Baurusuchus albertoi, within Baurusuchinae. Additionally, the remains of a sphagesaurid crocodyliform were preserved in the abdominal cavity of the new baurusuchid, what would be the first time that a direct and unmistaken evidence of predation is recorded in fossil Crocodyliformes. This new finding confirms the important position that crocodyliforms had in the trophic structure of that environment. The second part of this work presents a re-evaluation of the anatomy of Eocaiman cavernensis (Crocodylia, Caimaninae) from the Middle Eocene of Argentina. This species, described by G. G. Simpson in 1933, is important due to its ubiquitous presence in phylogenetic studies of Caimaninae. Thus, its re-description aimed at revealing new anatomical information in order to clarify the relationships among taxa of this group. The new data was added to a previously published phylogenetic analysis and the results were discussed. In addition, the paleobiogeography and paleoecology of the genus Eocaiman was evaluated in the context of the Caimaninae.

Com 23-24 espécies viventes, a diversidade atual de crocodilianos é irrisória quando comparada ao registro fóssil do grupo, principalmente se considerados todos os representantes de Crocodyliformes. À luz desta grande diversidade, este trabalho visou contribuir para o melhor entendimento da complexa história evolutiva dos crocodiliformes. Deste modo, são apresentados aqui, em duas partes distintas, os resultados obtidos durante o mestrado, que focou no estudo de dois Crocodyliformes fósseis. Na primeira parte, é descrita uma nova espécie de Baurusuchidae (Mesoeucrocodylia), baseada em um esqueleto completo coletado em General Salgado-SP (Formação Adamantina, Cretáceo Superior). Nomeado Aplestosuchus sordidus, o novo táxon foi incluído em uma análise filogenética no contexto dos Baurusuchidae, sendo posicionado em Baurusuchinae, como grupo-irmão com Baurusuchus albertoi. Além disso, na cavidade abdominal deste espécime, restos de outro indivíduo, associado a Sphagesauridae, foram preservados, revelando o primeiro registro inequívoco de conteúdos abdominais para Crocodyliformes fósseis. Assim, também é discutida a estrutura trófica do ambiente daquela época, amplamente dominada por crocodiliformes. Já a segunda parte envolveu a redescrição anatômica de Eocaiman cavernensis (Crocodylia, Caimaninae) do Eoceno Médio da Argentina. Esta importante espécie é presença constante em estudos filogenéticos sobre Caimaninae, sendo que a reavaliação de sua osteologia visou gerar novas informações anatômicas. Tais dados foram incorporados numa análise filogenética, no intuito de testar sua influência sobre a filogenia dos Caimaninae e demais Crocodylia. Adicionalmente, também foram desenvolvidas discussões acerca da paleobiogeografia e paleoecologia do gênero Eocaiman no contexto dos Caimaninae. / Crocodyliformes were much more diverse in the past than today. This incredible diversity is translated into a wide range of ecological niches occupied by these animals, many of which differ from the typical semiaquatic habit of the extant forms. In this context, the project developed during the MSc degree aimed to increase the knowledge about Crocodyliformes, with the study two fossil taxa, presented here in two separated parts. The first part includes the description of Aplestosuchus sordidus, a new species of Baurusuchidae (Mesoeucrocodylia), based on a nearly complete skeleton collected in deposits of the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). A phylogenetic analysis was performed to investigate the affinities of the new taxon, suggesting its sister-taxon relation to Baurusuchus albertoi, within Baurusuchinae. Additionally, the remains of a sphagesaurid crocodyliform were preserved in the abdominal cavity of the new baurusuchid, what would be the first time that a direct and unmistaken evidence of predation is recorded in fossil Crocodyliformes. This new finding confirms the important position that crocodyliforms had in the trophic structure of that environment. The second part of this work presents a re-evaluation of the anatomy of Eocaiman cavernensis (Crocodylia, Caimaninae) from the Middle Eocene of Argentina. This species, described by G. G. Simpson in 1933, is important due to its ubiquitous presence in phylogenetic studies of Caimaninae. Thus, its re-description aimed at revealing new anatomical information in order to clarify the relationships among taxa of this group. The new data was added to a previously published phylogenetic analysis and the results were discussed. In addition, the paleobiogeography and paleoecology of the genus Eocaiman was evaluated in the context of the Caimaninae.

Ultraviolet light is damaging but fish have evolved protective mechanisms, which allows them to live in shallow water reefs, high in UV radiation. This thesis details my investigation into the physiological ecology of solar ultraviolet (UV) absorbing compounds, known as mycosporine-like amino acids found in the external epithelial mucus, and examines the supporting role potentially played by a UV-induced DNA repair mechanism in coral reef fish of the Indo-Pacific. Using reverse phase chromatography and UV spectrophotometry, I examined whether the distribution of MAA compounds across different areas of the body is correlated with differential UV exposure. Comparisons were made between the MAA content and the absorbance spectra of mucus from the dorsal, ventral, caudal and head body surface areas in five species of Scaridae (Chlorurus sordidus, Scarus schlegeli, S. niger, S. psittacus and S. globiceps) from Ningaloo Reef, Coral Bay, Western Australia. All fish analysed had at least five MAAs present, and results showed that fish had increased UV absorbance in mucus over the dorsal area, which receives the brunt of UV radiation. Little UV protection was found in mucus from the ventral area, which receives the lower level of UV radiation mostly via reflection of the sand and reef surfaces. Furthermore, UV absorbance per mg dry mucus versus standard fish length showed that there is a positive relationship in C. sordidus with increasing size. I examined whether there is a difference in the quantity of UV screening compounds found in the mucus of fish along a longitudinal geographical gradient from inshore reefs (Lizard Island, Great Barrier Reef) to the outer edge reefs to oceanic reefs (Osprey Reef). MAA absorbance increased with longitudinal distance from the mainland landmass of Australia to more oligotrophic outer reefs, where UV attenuation is reduced and the ocean is more transparent to UV wavelength. I determined that fish living on inshore, more turbid reefs where UV attenuation in shallow waters is high have lower levels of MAA protection than fish from clear oceanic reefs. Furthermore, there seems to be a direct relationship between light attenuation and exposure with the quantity of protective sunscreening found in the mucus of reef fish. It is know that UV irradiation decreases with water depth and that mucus from fish with deep habitats absorbs less UV than that of fish from shallow habitats. It is unknown however, whether this UV protection is variable within the same individuals and if so, how fast changes 11 occur. To test this, I relocated 9 ambon damselfish from a deep reef (18 m) to a shallow reef (1.5 m) to expose fish to increased levels of UV and relocated another 7 fish from a shallow to a deep reef to expose fish to decreased levels of UV. One week after relocation, all fish were returned to their original reef site to determine whether MAA levels would return to their initial levels. Fish relocated to a shallower depth were recovered and had a 60% (SD+/-2%) increase in mucus UV absorbance. Conversely, the fish relocated to a deeper depth were recovered and had a 41% (SD+/-1%) decrease mucus UV absorbance. No difference was found between UV absorbance of relocated and original fish at both depth. Six days after fish were returned to their original reef, mucus UV absorbance levels had returned to 67% +/- 4% of the original level. These results show that mucus UV absorbance is variable in individual ambon damselfish and that the sunscreen protection typical for a certain depth is reached in relocated fish within just a few days of relocation. The rate of MAA loss is higher than the accumulation of MAAs suggesting that diet is not the sole determining factor involved in the sequestration of MAAs to mucus. The cleaner fish Labroides dimidiatus performs a mutualistic service by removing ectoparasites such as gnathiid isopods as well other dead infected tissue from its clients. Cleaner fish however are also known to feed on client mucus. The benefits of eating mucus until recently were unclear. In this study, we analysed the mucus of several cleaner fish clients to determine whether mucus feeding has a nutritional advantage over gnathiids and whether cleaner fish obtain their own MAA protection through this dietary mucus ingestion. Results show that host fish that are infected with gnathiids of poor nutritional value, in contrast to those that harbour gnathiids with higher nutritional value, continuously exude mucus that has both high nutritional value and high MAA content. These findings support the conclusion that in a competitive market for cleaners some host fish are forced to offer more than parasites to cleaners. Ultraviolet light that is not filtered by UV absorbing compounds such as MAA may still lead to DNA damage such as the formation of cyclobutane pyrimidine dimers (CPDs) or 6-4 photoproducts (6-4 PPs). However, coral reef fish have alternative mechanisms to overcome UV induced damage via the photolyase DNA repair mechanisms. We experimentally demonstrated for the first time that a coral reef fish species, the moon wrasse Thalassoma lunare has the ability to repair DNA damage via photoreactivation. Fish both with and without MAA protection were irradiated with UVB wavelength to induce DNA lesions. Half of the experimental fish were then exposed to photoreactivating wavelength to induce DNA repair 12 while the other fish were blocked from the repair mechanisms. Fish which had undergone DNA repair had the lowest number of lesions regardless of mucus MAA protection. When fish were blocked from photoreactivation wavelengths MAA sunscreens clearly served a photoprotective role. The amount of damage was greatest in fish which both lacked MAAs and which were also blocked from photoreactivating wavelengths. Thus for the overall UV protection of fish both the MAA sunscreens as well as the DNA repair system play a significant role in counteracting UV damage. Ultraviolet protection by MAA sunscreens is ubiquitous in marine fish. To date the same 5 MAA compounds (palythine (λmax 320 nm), asterina (λmax 330 nm), palythinol (λmax 332 nm), usujirene (λmax 357 nm) and palythene (λmax 360nm) have been identified in the mucus of several different species of reef fish from Australia. Here we report the first evidence of the presence of additional UV absorbing compounds found in the mucus of fish from Indonesia. Using UV spectroscopy the mucus of four species of fish was compared between both geographical regions. The presence of an additional peak between 294-296 nm wavelengths suggests the presence of gadusol and/or deoxygadusol, which are photoprotective compounds, thought to be the precursors of MAAs. Thus, UV protecting compounds in the mucus of fish may not be as conserved between different regions as previously assumed. Our knowledge concerning the effect of UV radiation has advanced considerably in the past decade and my research findings contribute to the better understanding of protective mechanisms of marine fish. The correlations I have found between UV attenuation/exposure, depth, and longitude of sampled individuals lead me to believe that mucus UV absorbing MAA compounds are a highly efficient adaptive defence.

El objetivo de esta Tesis Doctoral es estudiar diferentes herramientas para el manejo de plagas y enfermedades del cultivo de la platanera. Entre las herramientas que vamos a desarrollar, se van a analizar los compuestos orgánicos volátiles (COVs) fúngicos derivados de hongos entomopatógenos (HE) y nematófagos, como fuente de metabolitos con actividad antagónica contra el picudo negro (PN) de la platanera, Cosmopolites sordidus, para su control y manejo en el campo. Así mismo, vamos a estudiar las respuestas de cultivares de plataneras a quitosano, un polisacárido biodegradable, para evaluar su posible uso en el campo como estimulante y protector de las plantas frente a plagas y patógenos, como Fusarium oxysporum f. sp. cubense. El conjunto de capítulos de esta tesis pretende sentar las bases de una estrategia de manejo sostenible de plagas y enfermedades del cultivo de la platanera, basada en el uso de COVs derivados de hongos presentes de forma natural en los cultivos, en combinación con la suplementación de quitosano en el riego, para un efecto de protección y activación de las defensas de las plataneras antes de cualquier infección de plagas y/o enfermedades. El objetivo principal de esta Tesis Doctoral es encontrar nuevas fórmulas para la gestión integrada de plagas como Cosmopolites sordidus y enfermedades de la platanera en condiciones de campo. En esta Tesis Doctoral hemos ideado enfoques sostenibles para la gestión de las plagas y enfermedades de las plataneras. Nuestros objetivos son: a) Cosmopolites sordidus (picudo negro de la platanera, PN), la principal plaga de los cultivos de plátano y, b) el hongo del marchitamiento Fusarium oxysporum f. sp. cubense Raza Tropical 4 (FocTR4), agente causante de una nueva variante extremadamente virulenta de la enfermedad del “Mal de Panamá”, que se está extendiendo rápidamente por todo el mundo. Nuestras herramientas de gestión sostenible son: a) los hongos entomopatógenos (HE, conocidos por su uso como agentes de control biológico, ACBs) aislados de campos comerciales de plátanos, b) sus compuestos orgánicos volátiles (COVs) y, c) el quitosano, un compuesto biodegradable y elicitor de la inmunidad de las plantas con actividad antimicrobiana. Damos evidencia de que los COVs de los hongos agentes de control biológico son repelentes del PN. Pueden utilizarse en los cultivos de platanera mediante estrategias de push and pull para gestionar la plaga de forma sostenible. El quitosano puede utilizarse en el riego para prevenir las defensas de la platanera local y sistémicamente. Por lo tanto, este polímero, con probada actividad antimicrobiana frente a otros patógenos de marchitamiento de Fusarium spp., podría utilizarse contra la actual pandemia en las plataneras causada por FocTR4. La capacidad de inducir reguladores del crecimiento de las plantas sostiene también el papel fertilizante del quitosano. La inducción de compuestos relacionados con la respuesta sistémica adquirida (RSA) hace que el riego con quitosano sea una herramienta para manejar también las plagas de las plataneras sobre el suelo (PN) y las enfermedades (Sigatoka). De esta manera, los COVs y el quitosano podrían ayudar a reducir el uso de agroquímicos tóxicos en los cultivos de platanera en todo el mundo.