Refine
Document Type
- Article (2)
- Part of Periodical (2)
- Doctoral Thesis (1)
Language
- English (5)
Has Fulltext
- yes (5) (remove)
Is part of the Bibliography
- no (5) (remove)
Keywords
- Indian Ocean (5) (remove)
Institute
New species in Anatoma Woodward, 1859 (Anatomidae, Vetigastropoda) are found in abyssal hydrothermal vent field habitats on the oceanic plate margins in the Indian Ocean. Six species are identified using molecular sequence analyses of which four species are described as new based on their morphological characters: Anatoma discapex sp. nov., Anatoma declivis sp. nov., Anatoma laevapex sp. nov. and Anatoma paucisculpta sp. nov. Inadequate material was available for a morphological description of the other two species with genetic identification, but it is likely that all six species are new to science and endemic to the Indian Ocean. The northern Central Indian Ridge localities are dominated by Anatoma declivis sp. nov.; its closest relative is Anatoma discapex sp. nov. which occurs in the central area near the Rodriguez Triple Junction. Anatoma laevapex sp. nov. and Anatoma paucisculpta sp. nov. as well as a fifth undescribed species are mainly found on the Southeast Indian Ridge.
The diversity of Porifera from Ponta do Ouro (Mozambique) has been evaluated; this paper presents the first taxonomic effort devoted to sponges in the area, while studies of closeby areas are quite dated. Overall, 55 specimens were examined, leading to 26 described species; among these, four are new (Hyattella sulfurea Calcinai & Belfiore sp. nov., H. pedunculata Calcinai & Belfiore sp. nov., Amphimedon palmata Calcinai & Belfiore sp. nov. and Phoriospongia mozambiquensis Calcinai & Belfiore sp. nov.) and four (Chondrosia corticata Thiele, 1900, Callyspongia (Cladochalina) aerizusa Desqueyroux-Faundez, 1984, Clathria (Thalysias) hirsuta Hooper & Levi, 1993 and Ciocalypta heterostyla Hentschel, 1912) are new records for the Indian Ocean. For Callyspongia (Euplacella) abnormis Pulitzer-Finali, 1993, Callyspongia (Callyspongia) pulitzeri Van Soest & Hooper, 2020 and Amphimedon brevispiculifera (Dendy, 1905) this represents the first record after their initial discovery. The majority of the species have a wide distribution in the Indo-Pacific Ocean, but species from South and East Africa have also been recorded. These data highlight the characteristic of Ponta do Ouro as a transitional zone, located between a tropical and temperate biogeographic province, as well as the importance of increasing biodiversity knowledge of this biogeographic border to monitor possible shifts in the area as a consequence of climate crisis.
Deep-water species from the western Indian Ocean off the East African coast and Madagascar, belonging to the subfamily Photinae, are discussed and compared with species from the West Pacific. Phos elegantissimus Hayashi & Habe, 1965, P. hirasei Sowerby, 1913 and P. laevis Kuroda & Habe in Habe, 1961 are recorded from Mozambique and/or from Madagascar, hereby extending their known range considerably into the western Indian Ocean. The East African specimens formerly assigned to Phos roseatus Hinds, 1844 are found to differ from this West Pacific species. In total, five species are described as new: Phos ganii sp. nov., P. geminus sp. nov., P. ladoboides sp. nov., P. pulchritudus sp. nov. and P. testaceus sp. nov.
Pristomerus species of Madagascar are revised. We report 15 species, of which 12 are newly described: P. guinness sp. nov., P. hansoni sp. nov., P. kelikely sp. nov., P. keyka sp. nov., P. moramora sp. nov., P. melissa sp. nov., P. patator sp. nov., P. ranomafana sp. nov., P. roberti sp. nov., P. vahaza sp. nov., P. veloma sp. nov. and P. yago sp. nov. Pristomerus albescens (Morley) and P. cunctator Tosquinet are newly recorded from Madagascar and new host and/or distribution records are provided for this species. A dichotomous key to all species is provided. The zoogeographical relation of the Malagasy fauna of Pristomerus with respect to mainland Africa is discussed: only three of the 15 species are reported to occur outside of Madagascar, suggesting a high level of endemism in Madagascar which was not unexpected.
Until now, the NW Indian Ocean was sparsely covered with coral proxy records, and records from the Maldives Archipelago do not exist. The first such coral proxy record from the central Maldives is presented in this study. It originates from a massive Porites lutea (Quoy and Gaimard, 1833) colony that was sampled March 2007 in the lagoon of Rasdhoo Atoll (4°N/ 73°W), which is located in the central Maldives. The record spans a period of 90 yrs and reaches back to 1917 AD with monthly to bimonthly resolution. This study investigates temporal variations of the skeletal stable oxygen (delta18O) and carbon (delta13C) isotopes, the strontium-to-calcium (Sr/Ca), and the annual extension-rates, and their relationship to historical climate variations 1917-2007. Annual extension-rates show an increase over the 20th century, and are correlated with instrumental sea surface temperatures (SST). The interannual variation of the extension-rates within 2.5-4 years is driven by the El Niño-Southern Oscillation (ENSO). The amount of skeletal extension during the summer months is triggered by variations in the strength of the SW monsoon. Interannual and decadal variability in monsoon current activity (18-19 yrs) and rainfall over India are an expression of the summer monsoon strength. This is the reason why a statistical link between coral extension-rates and precipitation over India can be established. This implies that annual extension-rates in corals can be used as a new proxy for Indian monsoon variability on decadal resolution. The delta18O record exhibits the 20th century warming trend that is influenced by the effect of monsoon-induced cooling. delta18O also reveals interannual ENSO triggered variability, which is due to ENSO-forced variations in SST and sea surface salinity (SSS). A decadal variation at 12-14 yrs cannot be linked to SST variations in the NW Indian Ocean, but with decadal variations of SSS. They could be caused by ENSO- forced variations of the monsoon currents during the mature phase of ENSO teleconnections in the Indian Ocean in boreal winter. The Sr/Ca record does not indicate a significant warming, in spite of the observed SST rise at the sampling site. Changes in seawater Sr/Ca cannot be excluded. Nevertheless, interannual ENSO forcing is still evident. Evidence for the Pacific Decadal Oscillation (PDO) is found during 1917-1955. Afterwards, the Sr/Ca data indicate the disappearance of PDO forcing. By the combination of Sr/Ca and delta18O it is possible to detect ~80% of historical El Niño and La Niña events at the sample site. This study confirms the notion that interannual to multi-decadal climate fluctuations in the Pacific play a crucial role for climate variability in the Indian Ocean.