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Introduction Raoellidae are small artiodactyls retrieved from the middle Eocene of Asia (ca - 47 Ma) and closely related to stem Cetacea. Morphological observations of their endocranial structures allow for outlining some of the early steps of the evolutionary history of the cetacean brain. The external features of the brain and associated sinuses of Raoellidae are so far only documented by the virtual reconstruction of the endocast based on specimens of the species Indohyus indirae. These specimens are however too deformed to fully access the external morphology, surface area, and volume measurements of the brain. Methods We bring here new elements to the picture of the raoellid brain by an investigation of the internal structures of an exceptionally well-preserved cranium collected from the Kalakot area (Jammu and Kashmir, India) referred to the species Khirtharia inflata. Micro-CT scan investigation and virtual reconstruction of the endocast and associated sinuses of this specimen provide crucial additional data about the morphological diversity within Raoellidae as well as reliable linear, surfaces, and volumes measurements, allowing for quantitative studies. Results We show that, like I. indirae, the brain of K. inflata exhibits a mosaic of features observed in earliest artiodactyls: a small neocortex with simple folding pattern, widely exposed midbrain, and relatively long cerebellum. But, like Indohyus, the brain of Khirtharia shows unique derived characters also observed in stem cetaceans: narrow elongated olfactory bulbs and peduncles, posterior location of the braincase in the cranium, and complex network of blood vessels around the cerebellum. The volume of the brain relative to body mass of Khirtharia inflata is markedly small when compared to other early artiodactyls. Conclusion We show here that, cetaceans that nowadays have the second biggest brain after humans, derive from a group of animals that had a lower-than-average expected brain size. This is probably a side effect of the adaptation to aquatic life. Conversely, this very small brain size relative to body mass might be another line of evidence supporting the aquatic habits in raoellids.

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

Abstract Mercantour National Park (France) is recognized as a highly heterogeneous region with extremely varied geology, geomorphology and climatology, resulting in an exceptional biodiversity. From a hydrogeological point of view, it is also an area organized of small and discontinuous aquifers, their obligate groundwater fauna remaining absolutely unknown. This work explores the species richness of groundwaters in Mercantour National Park, using a sampling design at the catchment (six major valleys) and aquifer scales (aquifers in consolidated rocks and unconsolidated sediments). A major finding of this study is the discovery of 44 species restricted to groundwater, from which 43 are new to the Park and 10 are new to Science. Although a relatively small number of sites were sampled (53), the area may be considered as a new hotspot of groundwater biodiversity at the European level. The particular structure of the groundwater network, the high environmental heterogeneity of the region, and its Mediterranean position may explain such a high biodiversity. Species rarefaction curve showed that many species have yet to be discovered in groundwater of the Mercantour National Park. With more than 78% of species collected in the hyporheic zone, this study also highlights the importance of porous aquifers in sustaining groundwater biodiversity of mountainous regions. Key words: groundwater invertebrates, stygobionts, biodiversity hotspot, Mercantour National Park, hyporheic zone, spring. Résumé Biodiversité dans les eaux souterraines de montagne. Le Parc National du Mercantour: un ‘hotspot’ européen. Le Parc National du Mercantour est une région physiquement très hétérogène, avec des faciès géologiques, géomorphologiques et climatologiques extrêmement variés, à l’origine d’une biodiversité exceptionnelle. D'un point de vue hydrogéologique, son réseau souterrain est organisé en aquifères discontinus et de petite taille, dont la faune aquatique (stygobie) est aujourd’hui inconnue. Ce travail explore la richesse spécifique des eaux souterraines du Parc National du Mercantour, après la mise en œuvre d'un plan d'échantillonnage prenant en compte l'hétérogénéité environnementale à l’échelle du bassin versant (six vallées majeures) et de l'aquifère (aquifère fissuré ou poreux). Le premier fait marquant est la récolte de 44 espèces stygobies, 43 étant nouvelles pour le parc et 10 nouvelles pour la Science. Sur la base d’un nombre relativement faible de sites (53), cette zone peut être considérée comme un nouveau ‘hotspot’ de biodiversité des eaux souterraines à l'échelle européenne. La structure particulière du réseau hydrogéologique, l'hétérogénéité environnementale élevée, et la position méditerranéenne de cette région, pourraient expliquer une telle biodiversité. La courbe de raréfaction des espèces montre que nos connaissances sur le Mercantour sont néanmoins loin d'être complètes et que de nombreuses espèces restent encore à découvrir. Avec plus de 78 % des espèces récoltées dans la zone hyporhéique, ce travail souligne également le rôle des aquifères poreux, dans le maintien de la biodiversité des eaux souterraines de montagne. Mots-clés: invertébrés souterrains, stygobies, ‘hotspot’ de biodiversité, Parc National du Mercantour, zone hyporhéique, source.

When accidentally introduced in a new location, a species does not necessarily readily become invasive, but it usually needs several years to adapt to its new environment. In 2009, a national mosquito survey (MODIRISK) reported the introduction and possible establishment of an invasive mosquito species, Aedes j. japonicus, in Belgium. First collected in 2002 in the village of Natoye from a second-hand tire company, then sampled in 2003 and 2004, the presence of adults and larvae was confirmed in 2007 and 2008. A repeated cross-sectional survey of Ae. j. japonicus was then conducted in 2009 in Natoye to study the phenology of the species on two different sites using three kinds of traps: Mosquito Magnet Liberty Plus traps, BG sentinel traps and CDC Gravid traps. An analysis of the blood meals was done on females to assess the epidemiological risks. Five species of mosquitos were caught using the different kind of traps: Culex pipiens, Cx. torrentium, Anopheles claviger, Aedes geniculatus and Ae. j. japonicus, Cx. pipiens being the most abundant. The CDC gravid traps gave the best results. Surprisingly Ae. j. japonicus was only found on one site although both sites seem similar and are only distant of 2.5 km. Its population peak was reached in July. Most of the engorged mosquitoes tested acquired blood meals from humans (60\%). No avian blood meals were unambiguously identified. Larvae were also collected, mostly from tires but also from buckets and from one tree hole. Only one larva was found in a puddle at 100 m of the tire storage. A first local treatment of Ae. j. japonicus larvae population was done in May 2012 using Bacillus thuringiensis subsp. israelensis (Bti) and was followed by preventive actions and public information. A monitoring is also presently implemented.