The functional morphology of the heart/kidney complex, digestive system and mantle was investigated in Dentalium rectius (Mollusca, Scaphopoda). While encompassing in-depth examination of the diverse roles of each organ system, these studies also contribute towards an overview of metal processing by the organism. The heart/kidney complex departs substantially from typical molluscan form; morphological features demonstrate that the heart is reduced to a perianal sinus adjacent to the pericardium. Excretory function appears to be maintained, however, pericardial podocytes and a right renopericardial connection indicate that a blood ultrafiltrate passes to the kidney. Urine is modified by two nephrocyte types. While one may effect reabsorption, both secrete calcium, zinc and phosphate-containing granules into the urine. Intracellular granules of the digestive system also contain calcium phosphate; iron is the only other metal accumulated, principally by oesophageal and stomach epithelia. Iron uptake occurs via digestive cells and by both undifferentiated and specialized mantle epithelia. Iron-containing granules, released into the haemocoel by the mantle epithelium, are phagocytosed and transported by amoebocytes. Iron is not excreted by the kidney, but by oesophageal secretion into the gut lumen and by radular mineralization, differing significantly from iron processing reported in other molluscs. In addition to iron uptake, mantle functions include the creation of respiratory currents, gas exchange and sensory reception; the respective epithelial specializations described here constitute functional equivalents to ctenidia and osphradia, organs which are absent in this molluscan class. The ciliated bands of the mid-mantle region include supporting cells which possess high-domed, microvillous apices that facilitate diffusion between the mantle cavity and underlying haemocoel. The posterior region of the mantle is richly endowed with innervated cells, considered putative sensory receptors. Cilia number, length and ultrastructure define three receptor types. They are heterogeneously distributed among specific regions of the pavilion, and probably function in respiratory current testing. The maintenance of respiratory current passage to the scaphopod mantle cavity requires a secondary increase in posterior aperture size, which is otherwise progressively diminished by normal shell growth. Such an increase occurs in D. rectius, and is effected by periodic shell decollation through dissolution by the posterior mantle. / Graduate

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Στην παρούσα διπλωματική εργασία θα παρουσιαστούν τα αποτελέσματα από τα μάκρο- απολιθώματα που βρέθηκαν και συλλέχθηκαν στην ευρύτερη περιοχή του Καστριτσίου. Η περιοχή του Καστριτσίου ανήκει στην υπο-λεκάνη του Ρίου που αυτή με την σειρά της ανήκει στην λεκάνη του Κορινθιακού (Kontopoulos, N. Zelilidis, A 1997 ). Η Ιζηματολογική ανάλυση της περιοχής μα έχει δείξει ότι έχουν αποτεθεί εναλλαγές λιμνοθαλάσσιων ιζημάτων και αλουβιακών ριπιδίων από το Ανώτερο Πλειόκαινο έως το Ανώτερο Πλειστόκαινο. Τα δείγματα εφόσον εντοπίσθηκαν, μεταφέρθηκαν στο εργαστήριο αρχικά για καθαρισμό και έπειτα μελετήθηκαν για να ταξινομηθούν με βάση τα χαρακτηριστικά τους. Τα δείγματα μας ανήκουν στην συνομοταξία των Μαλάκιων και διαχωρίστηκαν σε τρείς κύριες ομοταξίες των Διθύρων, των Γαστερόποδων και των Σκαφόποδων. Η λεπτομερής μελέτη των δειγμάτων μας έδειξε τα γένη τα οποία βρήκαμε και αναφέρουμε εν συνεχεία ονομαστικά: Cerastoderma edule, Ostrea edulis, Bittium reticulatum, Turritella communis, Nassarius reticulates, Antalis inaequicostata, Antalis vulgaris, Chama gryphoides, Aporrhais pespelecani. Τα Μαλάκια μας έδωσαν πληροφορίες για την θερμοκρασία, την αλατότητα, για το βάθος της περιοχής καθώς και για τα ιζήματα στα οποία αναπτύχθηκαν οι οργανισμοί κατά το Πλειστόκαινο. / -

For the west coast of North America, from northern California to southern Washington, a habitat suitability prediction framework was developed to support wave energy device siting. Concern that wave energy devices may impact the seafloor and benthos has renewed research interest in the distribution of marine benthic invertebrates and factors influencing their distribution. A Bayesian belief network approach was employed for learning species-habitat associations for Rhabdus rectius, a tusk-shaped marine infaunal Mollusk. Environmental variables describing surficial geology and water depth were found to be most influential to the distribution of R. rectius. Water property variables, such as temperature and salinity, were less influential as distribution predictors. Species-habitat associations were used to predict habitat suitability probabilities for R. rectius, which were then mapped over an area of interest along the south-central Oregon coast. Habitat suitability prediction models tested well against data withheld for crossvalidation supporting our conclusion that Bayesian learning extracts useful information available in very small, incomplete data sets and identifies which variables drive habitat suitability for R. rectius. Additionally, Bayesian belief networks are easily updated with new information, quantitative or qualitative, which provides a flexible mechanism for multiple scenario analyses. The prediction framework presented here is a practical tool informing marine spatial planning assessment through visualization of habitat suitability. / Graduation date: 2012