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Pešić, Vladimir, Smit, Harry, Mary, Nathalie J. (2021): Two new water mite species of the genus Hydrodroma Koch, 1837 from New Caledonia (Acari, Hydrachnidia: Hydrodromidae). Acarologia 61 (3): 581-590, DOI: 10.24349/aGHX-uIU1, URL: http://www1.montpellier.inrae.fr/CBGP/acarologia/article.php?id=4456

International audience; Aquatic biofilms are heterogeneous assemblages of microorganisms surrounded by a matrix of extracellular polymeric substances (EPS). Recent studies suggest that aquatic biofilms can physically act as sorptive sponges of DNA. We took the opportunity from already available samples of stone biofilms and macroinvertebrates specimens collected in parallel at the same sites to test the capacity of biofilms to act as DNA samplers of macroinvertebrate communities in streams. Macroinvertebrate communities are usually studied with metabarcoding using the DNA extracted from their bodies bulk samples, which remains a time-consuming approach and involves the destruction of all individual specimens from the samples. The ability of biofilms to capture DNA was explored on 19 rivers sites of a tropical island (Mayotte Island, France). First, macroinvertebrate specimens were identified based on their morphological characteristics. Second, DNA was extracted from biofilms, and macroinvertebrate communities were targeted using a standard COI barcode. The resulting morphological and molecular inventories were compared. They provided comparable structures and diversities for macroinvertebrate communities when one is working with the unassigned OTU data. After taxonomic assignment of the OTU data, diversity and richness were no longer correlated. The ecological assessment derived from morphological bulk samples was conserved by the biofilms samples. We also showed that the biofilm method allows to detect a higher diversity for some organisms (Cnidaria), that is hardly accessible with the morphological method. The results of this study exploring the DNA signal captured by natural biofilms are encouraging. However, a more detailed study integrating more replicates and comparing the biodiversity signal based on both morphological and molecular bulk macroinvertebrate samples to the one captured by biofilms will be necessary. Better understanding how the DNA signal captured by natural biofilms represents the biodiversity of a given sampling site is necessary before considering its use for bioassessment applications.

Eighteen new species of Oecetis are described, diagnosed, and illustrated from New Caledonia: Oecetis amphora sp. nov., Oecetis ovula sp. nov., Oecetis ramosa sp. nov., Oecetis loyolaensi sp. nov., Oecetis millei sp. nov., Oecetis christinae sp. nov., Oecetis rostrata sp. nov., Oecetis alicae sp. nov., Oecetis oxybelis sp. nov., Oecetis dorsospina sp. nov., Oecetis multidentata sp. nov., Oecetis gracilis sp. nov., Oecetis rostra sp. nov., Oecetis triramosa sp. nov., Oecetis flucta sp. nov., Oecetis nouvellecaledoniensis sp. nov., Oecetis variabilis sp. nov., and Oecetis ovata sp. nov. A diagnostic key is provided for males of Oecetis species of New Caledonia. The species display similarities in genitalic characteristics but also a high diversity of apomorphic features. The new species were collected from lotic habitats across most of Grande Terre.

New records of water mites (Acari: Hydrachnidia) from the Comoros are presented. One genus, i.e. Lagoenaxonopsalbia Pešić & Smit, and four species, i.e. Platymamersopsis mayottensis (Anisitsiellidae), Torrenticola mayottensis (Torrenticolidae), Lagoenaxonopsalbia comorosensis (Aturidae) and Djeboa davecooki (Mideopsidae) are described as new to science. Arrenurus comorosensis Pešić & Smit, 2015 is synonymized with Arrenurus flavus Smit, 2012. The first description of the female of Sterkspruitia comorosensis Pešić & Smit, 2015 is given. The number of water mites known from Comoros now tallies 17 species in ten families.

Tout spectateur du Tombeau d’Alexandre de Chris Marker (1992) est a meme de se rappeler les plans fantomatiques que le cameraman Yakov Tolchan fit a l’insu de Staline a la demande de Dziga Vertov : le maitre du Kremlin longe une facade et disparait. La sequence qui ne peut etre que decevante pour celui qui cherche a percer les secrets de l’homme d’Etat definit le pouvoir par la negative. La realite de celui-ci echappant a toute tentative d’approche et de connaissance est impossible a representer et fondamentalement inaccessible au citoyen. Nous pensons que La Conquete de Xavier Durringer et Pater d’Alain Cavalier, films sortis en 2011, envisagent le pouvoir de maniere differente, non plus comme quelque chose d’impossible a representer. Une configuration europeenne / mondiale difficile, une omnipotence financiere, les derives variees de pouvoirs pratiquant le nepotisme et le detournement de fonds publics, la perspective d’une election presidentielle et une impression generale de perte de sens ont certainement prepare nos deux cineastes a s’interroger et a observer les puissants. Cet article etudie comment Durringer et Cavalier mettent en scene les questions, les emotions, les dialogues, les postures de ceux travaillant au sein du pouvoir.

New taxa and previously unavailable life stages of known species of Diptera: Blephariceridae from New Caledonia are described. Curupirina comosipes sp. n. differs distinctly from the three named species in the genus. However, separating larvae of the other species was not possible. Descriptions of the male and first instar larva of Nesocurupira curtirostris Stuckenberg are added. All life stages of Stuckenbergina hystrix gen. et sp. n. are described. A single larva of it had in the past been reported as possible Paltostomatinae (today classified as a tribe, Paltostomatini). However, all New Caledonian net-winged midges belong to Apistomyiini. All are endemic, and three of them even of restricted distribution on the main island.

New records of water mites (Acari: Hydrachnidia) from the Comoros are presented. Two species new to science, Torrenticola comorosensis (Torrenticolidae) and Sterkspruitia comorosensis (Hygrobatidae) are described; the latter species is the second known species of the genus Sterkspruitia Cook, 2003. First records are given for Limnochares crinita Koenike, 1898 and Mamersella thienemanni K. Viets, 1929. Additional measurements, figures and information on the morphology are given for specimens assigned to the Monatractides ventriosus-species complex.

Helicopsyche trispina sp. n. is described from Grande Terre, New Caledonia, based on pharate males, larvae and pupae. The species appears to belong to the monophyletic New Caledonian Helicopsyche clade.

During a hydrobiological survey conducted by Nathalie Mary a number of water mites were collected on the Comoros. Aim of this research was to monitor temporal water quality trends in major surface streams throughout the Grande Terre of Mayotte, a French overseas department, and to monitor water quality trends in selected reference and very polluted sites, in order to develop a biotic index.

Three new species are described from the Comoros, an archipelago in the Indian Ocean: Teratothyasides scutulatus Smit & Pesic n. sp., Platymamersopsis comoros Smit & Pesic n. sp. and Atractides comorosensis Smit & Pesic n. sp. One species is reported new for the fauna of the Comoros, i.e. Monatractides ventriosa (K. Viets, 1916).

All stages of Simulium (Meilloniellum) adersi (Pomeroy) from Mayotte, Comoro archipelago are described in detail. This species is widespread on the African mainland and in Madagascar; morphological divergences from African material point towards the Mayotte entity being a separate, but closely related species. Biology of the species overall is reviewed and brief comments are made regarding habitats and biogeography of the Mayotte material.