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La description en 1998 de Phlebotomus riouxi a posé le problème de la diagnose différentielle délicate de la femelle avec celle d’une espèce affine : P. chabaudi. Le rôle suspecté de P. chabaudi dans la transmission de Leishmania killicki dans certains foyers tunisiens nous a amené, à partir de 37 spécimens algériens et tunisiens, à effectuer la caractérisation moléculaire de ces deux taxons. Les séquences du gène du cytochrome b (cyt b) de l’ADN mitochondrial individualisent clairement ces taxons et mettent en évidence une variabilité intraspécifique. L’analyse morphologique ne permet pas de différencier les femelles des deux espèces sur la base des caractères génitaux. Un caractère céphalique nouveau tenant à la présence de dents latérales antérieures sur l’armature pharyngienne de P. chabaudi, absentes chez P. riouxi, est proposé, mais un recours au typage moléculaire semble nécessaire pour une identification fiable.

Background: The Culicoides fauna of Algeria has been historically investigated, leading to the description of many new species by Kieffer in the 1920s, Clastrier in the 1950s or Callot in the 1960s and to a comprehensive inventory by Szadziewski in the 1980s. The emergence of bluetongue in the late 1990s enhanced Culicoides collections made in the country over the last two decades, but information remained mostly unpublished. The aim of this study is therefore to provide a comprehensive and updated checklist of Culicoides biting midge species in Algeria., Methods: The literature (published and grey, in French and in English) from 1920 to date on Culicoides collections in Algeria was collected and analyzed in the light of the current taxonomic and systematic knowledge and methods. Fresh Culicoides material was also analyzed using light/suction trap collections carried out from November 2015 to September 2018 in nine localities of the 'wilayah' of Tiaret (northwestern Algeria). Slide mounted specimens were identified morphologically using the interactive identification key IIKC and original descriptions. Specimens were then compared with non-type material originating from different countries and partly with type material., Results: A total of 13,709 Culicoides, belonging to at least 36 species within 10 subgenera, were examined leading to 10 new records in Algeria, including C. chiopterus, C. dewulfi, C. navaiae, C. grisescens, C. paradoxalis, C. shaklawensis, C. simulator, C. univittatus, C. achrayi and C. picturatus. These new records and all previous records provided by the literature review were discussed., Conclusions: We propose a Culicoides checklist for the Algerian fauna of 59 valid species, including species mainly with a large Palaearctic distribution and a specific Mediterranean distribution, and only a few species from the Afrotropical region. Among them, several species, mainly of the subgenera Avaritia and Culicoides, are confirmed or probable vectors of arboviruses important in animal health.

In 1998, the description of Phlebotomus riouxi emphasised the difficulty to differentiate the female from the closely related P. chabaudi, a suspected vector of Leishmania killicki in several foci in Tunisia. In order to be able to distinguish the females of these two species, we started a molecular study based on 37 Algerian and Tunisian specimens. The alignment of the sequences of the cytochrome b of the mitochondrial DNA and their analysis using Neighbor-Joining, maximum likelihood and maximum parsimony shows the individualisation of two species including an intraspecific variability. Following a morphological approach, it is not possible to distinguish the females on the basis of their spermathecae. A new character is proposed: the presence of anterolateral teeth of the pharyngeal armature for P. chabaudi, never observed in P. riouxi. However, a molecular typing is necessary at the present time for a sure identification of the females.