Review of the Merodon natans group with description of a new species, a key to the adults of known species of the natans lineage and first descriptions of some preimaginal stages

Snežana Radenković,Maja Arok,Santos Rojo,Ante Vujić,Sanja Veselić,Ljiljana Šašić Zorić,André Van Eck,Ximo Mengual,Jelena Ačanski,Andrijana Andrić,Andrea Aracil,Tamara Tot,Celeste Pérez-Bañón

doi:10.3897/asp.79.e65861

Abstract

Abstract Merodon natans group (Diptera, Syrphidae) taxa are reviewed using an integrative taxonomic approach combining morphological, morphometric and molecular techniques. The approach substantiates recognition of the three species: M. calcaratus (Fabricius, 1794), M. natans (Fabricius, 1794) and M. pulveris Vujić &amp; Radenković in Radenković et al. 2011, and reveals the existence of a new species, M. makrisi Vujić, Radenković &amp; Tot sp. nov., which is described. It also highlights the existence of a series of natans group populations, especially on some of the Mediterranean islands, in the Levant and in the Afrotropical Region, for which more comprehensive data are required to clarify their status. A key is provided to the natans lineage species currently recognised, and preimaginal stages of some natans-group species are described for the first time. Redescriptions for M. calcaratus and M. natans are provided. A neotype is selected for M. natans. Lectotypes are designated for M. annulatus (Fabricius, 1794) and M. melancholicus (Fabricius, 1794). Merodon annulatus is recognised as a synonym of M. natans.

Highlights

The phytophagous hoverfly genus Merodon Meigen, 1803 (Diptera, Syrphidae) contains 234 species distributed in the Palaearctic and Afrotropical regions, and introduced into North America and New Zealand (Vujić et al 2021)
The Merodon natans species group (Fig. 3) contains medium sized, black, short pilose species characterized by the following diagnostic features: scutum with distinct white pollinose ornamentation, vittae and fasciae; terga 2–4 with broad white pollinose fasciae, which may be interrupted in the middle; legs black, except reddish-brown tibiae darkened in the middle and reddish-brown first and second tarsomeres of pro, meso- and metalegs; in some specimens the base and apex of femora yellowish
The integrative taxonomy approach using multiple data sources implemented in this study supports species delimitation based on morphological differences within the M. natans group

Summary

Introduction

The phytophagous hoverfly genus Merodon Meigen, 1803 (Diptera, Syrphidae) contains 234 species distributed in the Palaearctic and Afrotropical regions, and introduced into North America and New Zealand (Vujić et al 2021). An integrative taxonomic approach combining morphological and molecular information has been useful in resolving taxonomic problems in hoverflies (e.g., Marcos-García et al 2011; Nedeljković et al 2013, 2015, 2020; Vujić et al 2013, 2020b, 2020c; Haarto and Ståhls 2014; Popović et al 2015; Ačanski et al 2016; Šašić et al 2016; Kočiš Tubić et al 2018; Šašić Zorić et al 2018, 2020; Radenković et al 2018a, 2020; Arok et al 2019; Djan et al 2020)

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Conclusion