Are Appearances Deceiving? Morpho-Genetic Complexity of the Eumerus tricolor Group (Diptera: Syrphidae) in Europe, with a Focus on the Iberian Peninsula

Abstract

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.

Local-Scale DNA Barcoding of Afrotropical Hoverflies (Diptera: Syrphidae): A Case Study of the Eastern Free State of South Africa

“…Despite its utility, however, DNA barcoding is not a panacea for the study of biodiversity. An integrative taxonomical approach including physiological and ecological features must be prioritised (e.g., Aguado-Aranda et al [ 13 ]; Porco et al [ 47 ]) since it provides additional data useful for separating cryptic diversity even in common species.…”

“…Most of these Afrotropical species were described centuries ago, and their morphological diagnoses have been used in various studies without thorough revisions to encompass as much species diversity as found within the region [ 11 , 12 ]. Although morphological diagnoses have their limitations, the method is very useful when used with molecular techniques [ 13 ]. This indicates the need to use an informative and effective molecular technique to assist in morphological identification as a prerequisite for efficient conservation [ 13 ].…”

“…Although morphological diagnoses have their limitations, the method is very useful when used with molecular techniques [ 13 ]. This indicates the need to use an informative and effective molecular technique to assist in morphological identification as a prerequisite for efficient conservation [ 13 ].…”

Unveiling the Mainland vs. Insular Variability of the Eumerus barbarus Species Group (Diptera: Syrphidae) in the Western Mediterranean Basin

“…In this type of analysis, an approach combining different sources of data (morphological, genomic, and morphometrics) provides evolutionary clarification (e.g., [14,15]). However, as for phenotypic features, molecular features can also be variable; for example, while low interspecific variation in COI was revealed for certain species of the Eumerus tricolor (Fabricius, 1798) group [16], high levels of intraspecific variability (same molecular marker) have been found in another six Eumerus species from the Mediterranean basin [17].…”

“…A preliminary examination of material of the E. barbarus group from the islands and mainland from the western Mediterranean basin revealed a high morphological variability, mainly in E. barbarus and E. sulcitibius. Although previous studies have assessed variability using molecular markers for other Merodontini (e.g., [22]), few studies have assessed it in Eumerus (e.g., [16]). Therefore, the main aim of this work is to explore the phenotypic variability of the species of the E. barbarus group from the western Mediterranean basin in correlation with genetic data.…”