The Hautotara, Te Muna and Ahiaruhe Formations are formally described for the first time. The Hautotara Formation contains the littoral marine and estuarine deposits of the Huangarua Cyclothem together with underlying freshwater deposits which have been added for mapping convenience, and is considered to be late Marahauan (c. 1.2 to 1.05 Myr) in age. The Te Muna Formation is a conformable sequence, 366 m thick, containing fifteen members. Alluvial gravels alternate with freshwater blue-grey silt and sand with lignite layers, tree roots in growth position and occasional paleosols. The Te Muna Formation also contains loess at one horizon, and localised rhyolitic tephra beds. The tephras and preliminary paleomagnetism indicate a Castlecliffian age (c. 1.0 to 0.4 Myr). The Ahiaruhe Formation consists of alluvial gravel varying from a few metres to more than 80 m in thickness, interbedded with water-laid, partly loessic silts locally containing Mount Curl Tephra (c. 0.23 ± 0.04 Myr; equals Ahiaruhe Tephra). It has a tilted but still well-defined depositional surface at the top forming terraces, and passes laterally westward to thick blue-grey lacustrine silt with a moa footprint and also containing Mount Curl Tephra. The tephra indicates an age greater than 0.2 Myr for the the base of the Ahiaruhe Formation and less than 0.26 Myr for the top. Kawakawa Tephra in overlying loess indicates an age greater than 0.02 Myr. The three formations correspond to most of the time represented by the late Nukumaruan Stage, Castlecliffian Stage and early Hawera Series. We infer that their deposition was controlled by climatic fluctuations and associated glacioeustatic sea-level changes coincident with Milankovitch cycles, superimposed on secular vertical tectonic movements.

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The benthic foraminifer Virgulinella fragilis Grindell and Collen 1976 has multiple putative symbioses with both bacterial and kleptoplast endobionts, possibly aiding its survival in environments from dysoxia (5-45 μmol-O2 /L) to microxia (0-5 μmol-O2 /L) and in the dark. To clarify the origin and function of V. fragilis endobionts, we used genetic analyses and transmission electron microscope observations. Virgulinella fragilis retained δ-proteobacteria concentrated at its cell periphery just beneath the cell membranes. Unlike another foraminifer Stainforthia spp., which retains many bacterial species, V. fragilis has a less variable bacterial community. This suggests that V. fragilis maintains a specific intracellular bacterial flora. Unlike the endobiotic bacteria, V. fragilis klepto-plasts originated from various diatom species and are found in the interior cytoplasm. We found evidence of both retention and digestion of kleptoplasts, and of fragmentation of the kleptoplastid outer membrane that likely facilitates transport of kleptoplastid products to the host. Accumulations of mitochondria were observed encircling endobiotic bacteria. It is likely that the bacteria use host organic material for carbon oxidation. The mitochondria may use oxygen available around the δ-proteobacteria and synthesize adenosine triphosphate, perhaps for sulfide oxidation.

used to assay the recent energetic importance of lagoons to M. alfredi; high-resolution tracking data provided information about how M. alfredi utilised lagoonal habitats over long and short time periods; acoustic cameras logged patterns of animal entrances and departures from lagoons; and photo identification/laser photogrammetry provided some insight into why they may be using this habitat. M. alfredi showed strong evidence of energetic dependence on lagoon resources during the course of the study and spent long periods of residence within lagoons or frequently transited into them from elsewhere. While within lagoons, they demonstrated affinities for particular structural features within this habitat and showed evidence of temporal patterning in habitat utilization. This work sheds light on how and why M. alfredi uses lagoons and raises questions about how this use may be altered in disturbed settings. More generally, these observations contribute to our knowledge of how to assess the ecological importance of particular habitats situated within the broader home range of mobile consumers.Abstract Quantifying the ecological importance of individual habitats to highly mobile animals is challenging because patterns of habitat reliance for these taxa are complex and difficult to observe. We investigated the importance of lagoons to the manta ray, Manta alfredi, a wide-ranging and vulnerable species in a less-disturbed atoll ecosystem. lagoons are highly sensitive to anthropogenic disturbance and are known to be ecologically important to a wide variety of mobile species. We used a novel combination of research tools to examine the reliance of M. alfredi on lagoon habitats. Stable isotope analysis was

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