The Pyrenean species of Chelidura (Dermaptera, Forficulidae)

The Pyrenees are inhabited by scattered populations of earwigs of the genus Chelidura Latreille, 1825. There is some controversy about the specific assignment of these populations: while most authors assign them to C. pyrenaica (Gené, 1832), other consider that C. aptera (Mégerlé, 1825) is also present in the Pyrenees. The main objective of this work was to revise the identity and synonyms of Pyrenean Chelidura. Specimens from recent fieldwork and collections (MNCN-CSIC) were used for morphological and molecular studies (cytochrome oxidase 1). All Pyrenean specimens shared similar cox1 sequences, very divergent from those of Alpine C. aptera. As a consequence, the variability observed in male cerci morphology from the Pyrenees, ranging from long and slightly curved to short and very curved, corresponded to C. pyrenaica, and the presence of C. aptera in the Pyrenees can be rejected. As previously suggested by Maccagno (1933) and Fontana et al. (2021), the revision of the synonymic list uncovered the misplacement of the name F. simplex Germar, 1825 under the synonymy of C. aptera, while it rather represents a synonym of C. pyrenaica (syn. nov.). Forficula simplex has nomenclatural priority over C. pyrenaica, however both names meet the requirements of the article 23.9.1 of the International Code of Zoological Nomenclature to retain the prevailing usage of C. pyrenaica (nomen protectum) over F. simplex (nomen oblitum). Additionally, we discuss the taxonomic status of Chelidura arverna David & Van Herrewege, 1973 stat. nov. from the French Massif Central.

Contribution to the survey of the heathlands of the french Massif central (habitats 4030 and 4060) : analysis of phytosociological data.

À partir d’un échantillonnage initial de 990 relevés de landes du Massif central français, issu de la bibliographie et de recherches récentes sur le terrain, les auteurs réalisent une analyse globale puis des analyses partielles en MTC, CCA et DCA sur 675 relevés concernant les étages montagnard moyen et subalpin. Les résultats de cette révision conduisent à la caractérisation de seize associations végétales dont cinq nouvelles et quarante-sept sous-unités. Le sud et l’est du Massif central, Cévennes, Vivarais, Margeride, jusqu’ici moins bien connus, apportent le plus grand lot de nouveautés phytosociologiques. Ces communautés appartiennent à 2 classes phytosociologiques (Loiseleurio procumbentis-Vaccinietea microphylli et Calluno vulgaris-Ulicetea minoris) et 3 alliances dont le Genisto pilosae-Empetrion hermaphroditi all. nov. et le Genisto pilosae-Vaccinion Braun-Blanq. 1926. La nomenclature et la syntaxonomie de cette dernière alliance sont discutées et modifiées et une sous-alliance nouvelle y est créée (Vaccinienion myrtillo-uliginosi suball. nov.). Les communautés étudiées se différencient principalement en fonction de la disparité climatique du Massif, le gradient altitudinal, le substrat géologique et la topographie. Elles peuvent constituer des végétations stables ou entrent dans des successions dynamiques conduisant à des stades boisés. Leur caractérisation contribue à la connaissance de la compartimentation biogéographique et bioclimatique du Massif central, en rapport notamment avec les différences liées à la pluviométrie estivale, entre montagnes volcaniques nord-occidentales sous influence océanique, massifs internes au caractère subcontinental et bordure méridionale sous influence méditerranéenne. De même les végétations étudiées confirment un étage subalpin supérieur dans les quelques massifs qui dépassent 1600 m. La hiérarchisation des variables écologiques discriminantes pour ces végétations, la description de leurs conditions stationnelles et leur caractérisation dynamique au sein des espaces sylvo-pastoraux, donnent des éléments pour la gestion et la conservation des habitats d’intérêt européens correspondants, en particulier 4030 and 4060.

New actinopterygians from the Permian of the Brive Basin, and the ichthyofaunas of the French Massif Central

A new actinopterygian fauna from the Permian of the Brive Basin (Corrèze, Massif Central, France) is described in detail. It is represented by a new pygopterid taxon, Briveichthys chantepieorum gen. et sp. nov., erected and described here on the basis of several well-preserved specimens showing peculiar characters in the bones of the skull roof, parasphenoid, bones of the cheek and opercular apparatus. Other specimens from this new fauna are also described; they are referred to Progyrolepis heyleri Poplin, 1999, also known in the Bourbon-l’Archambault Basin, and Aeduella cf. blainvillei, which is relatively common in the Permian of France. These discoveries show the importance of the Brive Basin which was previously considered as a rather barren basin in term of palaeontology. This new fauna from Brive is compared with the other Permian ichthyofaunas from France: it is less rich in terms of specimen numbers than the faunas of Bourbon-l’Archambault and Autun, but it is more diversified in terms of number of taxa than the faunas of Lodève and L’Argentière (Ardêche). These actinopterygians, together with other aquatic vertebrates (e.g., acanthodians, sharks etc.), were widespread and diversified in the Hercynian Mountain Chain during the Permian. They indicate that the French basins were connected in time and space. The wide distribution of these aquatic taxa may have been favoured by numerous hydric systems (lakes, rivers etc.) which were well developed under the tropical climate.

The tungsten-gold veins of Bonnac (French Massif central): new constraints for a Variscan granite-related genesis

In the Brioude-Massiac district (French Massif Central), a network of W-As-Bi-Au quartz veins constitutes the Bonnac deposit, where tungsten is the major economic element, together with high-grade gold (up to 15 g/t Au). The evolution of this mineralization has been divided into 3 stages: i) an early deep-seated wolframite-lollingite stage formed between 12 to 9 km, at up to 400°C, ii) a ductile/brittle deformation stage associated with scheelite and arsenopyrite deposition, with an estimated temperature of 430-380 °C; iii) a late stage controlled by fluid-overpressure at a depth of 7 to 5 Km and a temperature between 266 to 240 °C, marked by micro-fracturing, infilled by native bismuth, bismuthinite, hedleyite, electrum, pyrite and base-metals. Structural analysis, and apatite LA-ICP-MS U/Pb dating, demonstrate a spatial and temporal link between the emplacement of the peraluminous leucogranitic dykes and the Bonnac mineralization. In more details, the mineralization was deposited between 321-316 Ma, during or just after the emplacement of the peraluminous dykes emplaced around 329-315 Ma, suggesting a magmatic-hydrothermal transition for the ore-forming process. In the proposed model, the cooling of a hidden two-mica granitic pluton could have generated a magmatic fluid, and acted as the heat source responsible for fluid flow towards inherited permeability zones. The magmatic fluid was then re-equilibrated at high temperature by fluid-rocks interaction. The sharp changes in temperature, pressure, and sulfide-fugacity generated by a late input of meteoric fluid were responsible for the deposition of the late gold-stage. At the regional scale, the tungsten-gold event is ascribed to an early hydrothermal stage, dissociated from the formation of the antimony event in the district. The leucogranitic dykes and Bonnac quartz veins are controlled by a NW-SE stretching direction, interpreted as an expression of the Serpukhovian-Bashkirian syn-orogenic extension (D4 event of the French Massif Central). These new data provide evidence for an early tungsten and gold metallogenic event in the FMC, prior the “Or300” event. The genetic classification of the Bonnac mineralization is equivocal. The W-As-Bi-Au-quartz veins exhibit the features of both an “orogenic gold” deposit at a relatively deep emplacement level, and an Intrusion-Related-Gold-Deposit (IRGD) type with a spatial-temporal link with the peraluminous intrusion emplacement. We propose that the Bonnac deposits represent an intermediate type between a typical orogenic-gold deposit and an IRGD. We argue that the presence of this type of mineralization, and more generally the IRGD deposits, have been underestimated in the Variscan French Massif Central.