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ABSTRACT Although recognized as an outstanding hotspot of biodiversity for both flora and fauna, the Mercantour massif remains almost totally unexplored for its groundwater fauna. This work reports the first overview on groundwater oligochaete assemblages of the “Parc du Mercantour” after a standardized exploration of both consolidated (fractured massif) and unconsolidated (porous) aquifers. About 40 species of oligochaetes were found in 49 stations representative of the main hydrogeological basins of the “Parc du Mercantour”, from both spring and hyporheic zone habitats. Five stygobiont species are identified, probably all new to science, of which two species are formally described, Aberrantidrilus stephaniae n. gen., n. sp. (Naididae, Phallodrilinae) and Marionina sambugarae n. sp., a species belonging to the widespread Marionina argentea species complex (Enchytraeidae). As a result, the genus Abyssidrilus Erséus, 1992 is now restricted to its marine, abyssal species. A dozen of species can be considered as stygophiles. Most stygobiont species are recorded from hyporheic habitats, and stygophiles have a more balanced distribution between both kinds of habitats. The nearly absence of stygoxene species from the hyporheic zone suggests that this habitat is less affected by the epigean environment than springs. The dominance of enchytraeids among the groundwater oligochaete fauna is here confirmed, and the lumbriculid genus Trichodrilus is also a characteristic faunistic element of the underground freshwater oligochaete communities. Lastly, the possibility that Aberrantidrilus cuspis n. comb. sensu Sambugar et al. (1999) is a complex of cryptic species is discussed in the framework of recent progress in the knowledge of groundwater biodiversity. Key words: Aquatic Clitellata, Oligochaeta, groundwater, Mercantour, new species, Aberrantidrilus n. gen., Marionina, Abyssidrilus RESUME Oligochètes (Annelida, Clitellata) des eaux souterraines du Parc du Mercantour (France), avec description d’un nouveau genre et de deux nouvelles espèces stygobiontes. Bien qu’il soit reconnu comme un remarquable point chaud de biodiversité pour sa flore et sa faune, le massif du Mercantour reste presque totalement inexploré quant à sa faune souterraine. Ce travail rapporte le premier aperçu des assemblages d’oligochètes des eaux souterraines du « Parc du Mercantour », suivant une exploration standardisée des aquifères consolidés (massif fracturé) et non consolidés (poreux). Environ 40 espèces d’oligochètes ont été trouvées dans 49 stations représentatives des principaux bassins hydrogéographiques du « Parc du Mercantour », ainsi que des sources et de la zone hyporhéique. Cinq espèces stygobiontes ont été identifiées, probablement toutes nouvelles pour la Science, parmi lesquelles deux ont été formellement décrites, Aberrantidrilus stephaniae n. gen., n. sp. (Naididae, Phallodrilinae) et Marionina sambugarae n. sp., une espèce appartenant au complexe d’espèces Marionina argentea (Enchytraeidae) à large répartition. Il en résulte que le genre Abyssidrilus Erséus, 1992 est maintenant restreint à ses espèces marines et abyssales. Une douzaine d’espèces peuvent être considérées comme stygophiles. La plupart des espèces stygobiontes proviennent des habitats hyporhéiques tandis que les stygophiles se répartissent de façon plus équilibrée entre les deux types d’habitats. La quasi absence d’espèces stygoxènes dans la zone hyporhéique suggère que cet habitat est moins affecté par l’environnement épigé que les sources. La dominance des enchytréides au sein de la faune des oligochètes des eaux souterraines est ici confirmée, ainsi que le genre Trichodrilus en tant qu’élément faunistique le plus caractéristique des communautés des oligochètes des eaux douces souterraines. Enfin, la possibilité qu’Aberrantidrilus cuspis n. comb. sensu Sambugar et al. (1999) soit un complexe d’espèces cryptiques est discutée dans le cadre des progrès récents dans la connaissance de la biodiversité des eaux souterraines. Mots clés : Clitellata aquatiques, Oligochètes, eaux souterraines, Mercantour, nouvelles espèces, Aberrantidrilus n. gen., Marionina

Mertensiothuria is one of the 20 subgenera currently recognized under Holothuria. The diagnosis of the subgenus is amended with new information on the ossicles found in the longitudinal muscles. The number of species of Mertensiothuria considered to be valid at present is six. These species are redescribed on the basis of new material, type and non-type museum material and on re-evaluation of literature. Two of them, Holothuria hilla and Holothuria aphanes, are transferred from the subgenus Thymiosycia to Mertensiothuria. Four species formerly referred to Mertensiothuria are removed; provisionally they are not referred to any of the known subgenera of Holothuria. Full annotated descriptions or (where the type material was not available) references to the literature are given for each species. An identification key is given to the species belonging to the subgenus Mertensiothuria.

Abstract: Easter Island (or Rapa Nui), famous worldwide for its gigantic stone statues, is the most isolated inhabited island in the Pacific. Yet the history of its inhabitants has been far from peaceful: they have faced deforestation, slave raids, epidemics and colonialism. This paper aims to study the diet of the ancient Easter Islanders and focuses on dietary reconstruction through the analysis of human teeth and bones, more particularly, on the impact of gender, age, social status and spatial distribution. However, retrieving information on their dietary habits is difficult, due to the absence of written archives and the disappearance of most of the bearers of the indigenous culture during the slave raids and epidemics of the nineteenth century. Therefore our primary source of direct information are food remains (animal bones and plant remnants) and human bones. The individuals studied came from twenty sites, which date mainly from the seventeenth to the nineteenth centuries. The greater part had been buried in monuments (funerary stone platforms called ahu), or caves. These individuals are currently stored at the Royal Belgian Institute of Natural Sciences and the Father Sebastian Englert Anthropological Museum of Easter Island. Dietary reconstruction is based on stress indicators, dental microwear and stable carbon and nitrogen isotope analyses. Stress indicators are skeletal markers which reveal poor living conditions during growth. Two indicators were studied: dental enamel hypoplasia (localised defects in the tooth crown generally expressed in the form of horizontal depressions) and cribra orbitalia(porotic lesions in the bony orbital roof). Dental microwear is the study of the microscopic features that form on the teeth’s surfaces as a result of use. Their density, dimensions, and orientation are a direct result of diet. Stable isotope analyses are based on the fact that the isotopic composition of an individual’s tissues is determined by the proportion of the various foods consumed. Carbon and nitrogen stable isotope composition were analysed in the bone collagen. Dental microwear patterns indicated a large proportion of tubers in the Easter islanders’ diet. Additionally, the stable isotopes showed that, on average, one third of the dietary proteins were of marine origin and that children were breastfed until three years of age. Stress indicators suggest that infantile malnutrition was not severe. Our results also demonstrated gender disparity in access to food resources. Furthermore, the isotopic signatures clustered according to the place of burial (ahu), indicating family dietary specificities. Finally, our study revealed the influence of social status on food intake: individuals from Ahu Nau Nau, which is said to be the royal ahu, displayed the highest value of nitrogen and carbon isotopes and the lowest number of microwear features. A greater consumption of marine products may explain this distinction.