An updated checklist of the extant Western Palaearctic Dryininae (Hymenoptera, Dryinidae)

Abstract A checklist of 20 extant species of Dryininae (Hymenoptera, Dryinidae) from the Western Palaearctic subregion is presented.

A review of the Western Palaearctic Dryininae (Hymenoptera, Dryinidae) was published by , and he listed a total of nine species. However, in the last 25 years many additional papers on the Western Palaearctic fauna have been published, so that the number of species has increased to 20, and the need to develop a new checklist of Western Palaearctic Dryininae became evident. The objective of this checklist is to ease further studies on Palaearctic dryinids.

Material and methods
The present paper treats all extant Dryininae (fossil species are excluded) present in the Western Palaearctic subregion, i.e., according to Vigna Taglianti et al. (1992Taglianti et al. ( , 1999, the part of the Palaearctic region situated in Europe and Asia west to the Ural Mountains and Caspian Sea, from the Azores and Canary Islands to Iran (included). The borders are not always obvious and natural. The eastern boundary runs along the Ural Mountains and the eastern bank of Caspian Sea, reaching Iran. The Russian region situated immediately east of Ural Mountains in parts of Kazakhstan, Turkmenistan, and Iran should be considered transition country to the Eastern Palaearctic subregion, whereas a large part of the Arabian Peninsula should be considered a transition area to the Afrotropical region. All these transition areas are considered in this checklist. The knowledge of the dryinids living in the Western Palaearctic subregion is broadly insufficient, so that this checklist will need to be updated in the future following further research.
Distributional data of Dryininae in the Western Palaearctic region were compiled analysing all the avail able publications, in addition to many unpublished records obtained by identifying material belonging to various institutions.
Distribution. United Arab Emirates.

Discussion
Dryininae of the Western Palaearctic subregion are insufficiently known from many points of view. The 20 listed species are known mainly on the basis of only one sex (Derafshan et al. 2016;Olmi 1999Olmi , 2008Olmi and van Harten 2006;Olmi and Xu 2015). In fact, only females are known in 11 species (D. berlandi, dayi, delvarei, gharaeii, gryps, ibericus, maroccanus, tigarae, turcicus, tussaci, yemenensis). Both opposite sexes are known in six species (D. balearicus, collaris, corsicus, niger, sanderi, tarraconensis). In three species, the male was associated to the female tentatively, i.e. the association is doubtful (D. albrechti, canariensis, tamaricicola). This situation depends on the large morphological differences between female and male, so that the association of the opposite sexes is impossible, if it is not supported by rearings or DNA analysis. However, very few researchers rear dryinids or study their DNA.
The knowledge is insufficient also in the association of the species to their hosts. Dryinus species are parasitoids of Fulgoromorpha (Guglielmino et al. 2013). However, in the Western Palaearctic subregion, the hosts are known only in six species (D. balearicus, collaris, corsicus, niger, sanderi, tarraconensis). Also in this case, the situation depends on the scarcity of rearings.
From the biogeographical point of view, according to the categories presented by Vigna Taglianti et al. (1992Taglianti et al. ( , 1999 (endemic, Yemen, Oman). Eight species of the above list are considered endemic provisionally, because dryinids are understudied, so their geographic distribution could be larger. Olmi and Xu (2015) listed 10 species of Dryinus and one species of Pseudodryinus from the Eastern Palaearctic subregion. So the dryinid population of the two subregions has about the same numerical strength. However, the composition is different. Few species are present also in the Western Palaearctic subregion, i.e. D. collaris, D. corsicus, and D. tarraconensis.
Education, University and Research) initiative "Department of excellence" (Law 232/2016). This paper was supported by the National Natural Science Foundation of China (No. 3147207; responsible Jingxian Liu).