Systematic position and composition of Merodon nigritarsis and M. avidus groups (Diptera, Syrphidae) with a description of four new hoverflies species

Abstract

The putative monophyly and systematic position of Merodon nigritarsis group was assessed based on morphological and molecular data of the mitochondrial COI and nuclear 28S rRNA genes. The previously reported concept of the group has been redefined, and M. crassifemoris Paramonov, 1925 is now excluded. The related M. avidus group is redefined here, including the Merodon avidus complex and M. femoratus Sack, 1913. Species delimitation of morphologically defined species of M. nigritarsis group was well supported by COI gene analysis, with the exception of M. alagoezicus Paramonov, 1925 and M. lucasi Hurkmans, 1993. Descriptions are given for three new species of the M. nigritarsis species group: Merodon cohurnus Vujić, Likov et Radenković sp. n., Merodon longisetus Vujić, Radenković et Likov sp. n. and Merodon obstipus Vujić, Radenković et Likov sp. n., and one new species from the M. avidus group: Merodon rutitarsis Likov, Vujić et Radenković sp. n. A lectotype is designated for M. femoratus Sack, 1913, and two new synonymies of this species were proposed: M. biarcuatus Curran, 1939 and M. elegans Hurkmans, 1993. Here we review 18 species from the M. nigritarsis group and six species from the M. avidus group and provide morphological diagnoses of the species groups. Additionally, diagnosis of 12 branches (groups or individual taxa) of M. avidus-nigritarsis lineage, an illustrated diagnostic key for the males, and distribution map are provided for the new species.

Revision of the Merodon serrulatus group (Diptera, Syrphidae)

“…High level of inter-population molecular variability within M. serrulatus species was also detected. ance between morphological and molecular data has been observed in some previous studies concerning closely related taxa within the family Syrphidae (e.g., Ståhls et al 2009;Francuski et al 2014;Haarto and Ståhls 2014), as well as in recently conducted studies on Merodon species groups (Likov et al 2019). In the present study the molecular data for M. defectus sp.…”

“…Unfortunately, these two clades do not have support and the whole cluster, including M. sacki, could be resolved in a large polytomy when collapsing nodes without high support. Different molecular profile of different populations of one species was also detected by Likov et al (2019). The suggested reasons for the low COI divergence between these species are retained polymorphism or mitochondrial introgression between the taxa, as it has been hypothesized in previous studies (e.g., Ståhls et al 2009;Francuski et al 2014;Haarto and Ståhls 2014).…”

“…presented a phylogenetic inference where the Merodon avidus-nigritarsis lineage was resolved in a similar way as in the studies by Šašić et al (2016) and Radenković et al (2018b). In the same study, Likov et al (2019) divided the M. avidus-nigritarsis lineage into 10 species groups (namely M. aberrans, M. aurifer, M. avidus, M. clavipes, M. fulcratus, M. italicus, M. nigritarsis, M. pruni, M. serrulatus, and M. tarsatus groups), and five species were not included in any of these species groups (i.e., M. clunipes Sack, 1913, M. crassifemoris Paramonov, 1925, M. eumerusi Vujić, Radenković & Likov, 2019, M. murinus Sack, 1913, and M. ottomanus Hurkmans, 1993.…”

“…Taxon delimitation and integrative taxonomy Likov et al (2019) reported the monophyly of the Merodon avidus-nigritarsis lineage. Within this lineage, the Merodon serrulatus species group is supported in our phylogenetic analyses.…”

“…1). Based on recently published data, this group contains six already described species, i.e., Merodon bequaerti Hurkmans, 1993, M. hirsutus Sack, 1913, M. kawamurae Matsumura, 1916 (Paramonov, 1936), and M. serrulatus (Wiedemann in Meigen, 1822) (Likov et al 2019).…”