The scarce and biased knowledge about the diversity and distribution of Araneae species in the Iberian Peninsula is accentuated in poorly known habitats such as the Mesovoid Shallow Substratum (MSS). The aim of this study was to characterize the spiders inventory of the colluvial MSS of the Sierra de Guadarrama National Park, and to assess the importance of this habitat for the conservation of the taxon.Thirty-three localities were selected across the high peaks of the Guadarrama mountain range and they were sampled for a year using subterranean traps specially designed to capture arthropods in the MSS. Species accumulation curves were built both for the observed species richness and for the non-parametric richness estimators. The literature was reviewed in order to update the distributional maps of the rarest species.Forty-two species were collected, of which four were species new to science. More than half were represented by one or two individuals which caused the accumulation curves to rise slowly and to end without reaching an asymptote. Almost half of the species showed significant increases in their Iberian distribution ranges. Two species were recorded for the first time in the Iberian Peninsula and 32 species were new additions to the spider checklist of the Sierra de Guadarrama National Park.

The hoverfly genus Eumerus Meigen, 1822 (Eristalinae: Merodontini) comprises 250+ described species, of which 36 are reported from the Iberian Peninsula. The high species diversity linked to the low degree of morphological differentiation between some species, which is even lower in females, leads to a high taxonomic complexity in this genus. The aim of this work is to confirm the morphological and molecular validity of an undescribed species of Eumerus, which is widespread in the Iberian Peninsula. The new species is described and compared with similar species. The genitalia of the new species are similar to those of Eumerus clavatus Becker, 1923 and Eumerus uncipes Rondani, 1850, but also share some features with Eumerus nudus Loew, 1848. The COI-5’ barcode is provided for the new taxon and analysed together with those of other named Eumerus sequences/species publicly available online. In the light of the morphology and barcoding data, the systematic position of the new species is discussed.

Comprising nearly 300 described species, Eumerus Meigen, 1822, is one of the most speciose syrphid genera worldwide, and its taxonomic diversity is remarkable in the Mediterranean basin. The Eumerus barbarus (Coquebert, 1804) group consists of four species in the western Mediterranean. Although the phenotypic variability of this species group has been commented on in previous studies, it has never been contrasted with molecular data. In the present work, the morphological variation found in 300+ specimens of this species group from the western Mediterranean is explored and tested against the COI mitochondrial DNA (mtDNA). The highest phenotypic disparity was found in E. barbarus and Eumerus sulcitibius Rondani 1868. The integrative approach has not revealed cryptic diversity within the species E. barbarus but in E. sulcitibius. As a result, a new species close to E. sulcitibius was discovered, Eumerus sardus Aguado-Aranda, Ricarte & Hauser sp. n., from Sardinia, Italy. The new insular species is here described, illustrated, and discussed. A total of twenty-three haplotypes of COI mtDNA were identified amongst the analyzed Mediterranean specimens of E. barbarus, whereas two and five haplotypes were distinguished in the Iberian specimens of E. sulcitibius and Eumerus gibbosus van Steenis, Hauser & van Zuijen, 2017, respectively. Moreover, the first known barcodes of E. gibbosus and Eumerus schmideggeri van Steenis, Hauser & van Zuijen, 2017 were obtained, and the distribution ranges of all species are mapped. An updated dichotomous key to the males of the E. barbarus group from the western Mediterranean is provided.

The syrphid genus Eumerus Meigen, 1822 is one of the most speciose in the world. In the Ibero-Balearic area (including Andorra and the Spanish side of the Pyrenees), recent taxonomic studies have increased the knowledge of Eumerus in Europe. A high taxonomic diversity together with a complex morphology make species identification difficult in this genus. The lack of updated and comprehensive tools to assist in the identification of species prompted the production of a dichotomous key to all Ibero-Balearic species of Eumerus and generation of DNA barcodes for ten species. In summary, a total of 37 species of Eumerus and nine species groups are reported in this geographical region. Eumerus caballeroi Gil Collado, 1929 is proposed as junior synonym of Eumerus nudus Loew, 1848 and the taxonomic status of Eumerus pauper Becker, 1921 is discussed. The first sequences of the 5? region of the Cytochrome c oxidase subunit I gene (COI-5?) of Eumerus subornatus Clau?en, 1989 and Eumerus truncatus Rondani, 1868 were obtained and their systematic positions corroborated.

Eumerus Meigen, 1822 is one of the largest Syrphidae genera in the Palaearctic Region, with the highest levels of taxonomic diversity found in the Eumerus tricolor species group. Despite its high diversity, the interspecific levels of morphological variability can be low. Additionally, some species may show certain levels of intraspecific variability. Hence, species delimitation may become challenging. In this work, we assessed the diversity of the E. tricolor group in the Iberian Peninsula through an integrative analysis of nomenclature, morphology and the 5′ (COI-5′) and 3′ (COI-3′) end regions of the Cytochrome c oxidase subunit I gene. Two new species, Eumerus ancylostylus Aguado-Aranda & Ricarte sp. n. and Eumerus petrarum Aguado-Aranda, Nedeljković & Ricarte sp. n., were described, and their intra- and interspecific variations discussed. In addition, the first barcodes of Iberian members of the E. tricolor group were obtained, and the distribution ranges of all species were mapped within the study area. The systematic position of the new species is discussed based on the resulting COI-based trees. The male genitalia of Eumerus hispanicus van der Goot, 1966 and Eumerus bayardi Séguy, 1961 were studied and illustrated. A lectotype was designated for Eumerus lateralis (Zetterstedt, 1819). An updated dichotomous key for all known European species of the E. tricolor group is provided. The egg of E. petrarum sp. n. is also described.

Five genera of Brachyopini, Chrysogaster Meigen, 1800, Melanogaster Rondani, 1857, Lejogaster Rondani, 1857, Orthonevra Macquart, 1829 and Riponnensia Maibach et al. 1994a are here revised from the Iberian region. Two new species, Melanogaster baetica Ricarte and Nedeljković, sp. n. and Orthonevra arcana Ricarte and Nedeljković sp. n., are described from Spain, and a third species, Chrysogaster coerulea Strobl in Czerny and Strobl, 1909 stat. n., is reinstated as valid and redescribed. A lectotype is designated for Orthonevra plumbago (Loew, 1840). The holotype of Orthonevra incisa (Loew, 1843) and the lectotype of O. plumbago are described in detail and illustrated. Melanogaster baetica sp. n. is similar to Melanogaster parumplicata (Loew, 1840) in male genitalia morphology, while O. arcana sp. n. is similar to O. incisa in the entirely-pollinose sternum I and the conspicuous incision on the posterior margin of tergum V in female. The first Iberian record of Chrysogaster rondanii Maibach and Goeldlin de Tiefenau, 1995 is provided, whilst Melanogaster aerosa is removed from the Iberian checklist of Syrphidae. Identification keys are presented to the five Brachyopini genera and 18 species now reported from the Iberian Peninsula (Chrysogaster, 6 spp.; Lejogaster, 2 spp.; Melanogaster, 3 spp.; Orthonevra, 5 spp.; Riponnensia, 2 spp.). COI (Cytochrome c oxidase subunit I) barcodes of the two new species plus C. coerulea, Chrysogaster solstitialis (Fallén, 1817), Orthonevra nobilis (Fallén, 1817) and Orthonevra frontalis (Loew, 1843) were successfully obtained from Spanish specimens. A COI-based tree was produced to locate these taxa in a wider systematic framework within the tribe.