The Merodon planifacies subgroup (Diptera, Syrphidae) : Congruence of molecular and morphometric evidences reveal new taxa in Drakensberg mountains valleys (Republic of South Africa)

Hoverflies (Syrphidae) represent an insect group of great importance in ecosystems and indicators of ecosystem change. The genus Merodon Meigen, 1803 (tribe Merodontini) is one of the most species-rich hoverfly genera, distributed across the Palaearctic and Afrotropical regions. The genus Merodon Meigen, 1803 is less diverse in the Afrotropical Region than in the Palaearctic (11 versus 160 known species). An ongoing study of the genus Merodon in Africa has revealed the existence of two new species into the taxon previously known as Merodon planifacies Bezzi, 1915. The M. planifacies subgroup belongs to the Afrotropical lineage of the Merodon desuturinus group. Morphological analysis of male genitalia has classified the available specimens of the M. planifacies taxon into two sets: the first one corresponds to M. planifacies with folded theca, while the other with smooth theca, later named Merodon capi complex was found exclusively at the Drakensberg mountains in the Republic of South Africa, specifically in the Cathedral Peak National Park and the Royal Natal National Park. Further, molecular and morphometric evidences revealed two cryptic taxa within this complex: M. capi sp. nov. Vujic et Radenkovic and Merodon roni sp. nov. Radenkovic et Vujic. (c) 2020 Elsevier GmbH. All rights reserved.Peer reviewe

Revision of the Merodon serrulatus group (Diptera, Syrphidae)

The phytophagous hoverfly genus Merodon Meigen, 1803 (Diptera, Syrphidae), which comprises more than 160 species distributed in Palaearctic and Afrotropical regions, can be differentiated into multiple groups of species that harbor high levels of hidden diversity. In this work, the serrulatus species group of Merodon is revised, providing an illustrated key to species, a detailed discussion on the taxonomic characters and a morphological diagnosis, including also the first data about the preimaginal morphology of this species group. The study includes characteristics of the 13 species of the M. serrulatus group, along with the available distributional data. Moreover, descriptions are provided for seven new species, namely M. defectus Vujic, Likov & Radenkovic sp. nov., M. disjunctus Vujic, Likov & Radenkovic sp. nov., M. medium Vujic, Likov & Radenkovic sp. nov., M. nigrocapillatus Vujic, Likov & Radenkovk sp. nov., M. nigropunctum Vujic, Likov & Radenkovic sp. nov., M. opacus Vujic, Likov & Radenkovk sp. nov., and M. trianguloculus Vujic, Likov & Radenkovk sp. nov. In addition, the taxa M. serrulatus (Wiedemann in Meigen, 1822), M. bequaerti Hurkmans, 1993, M. birsutus Sack, 1913, M. kawamurae Matsumura, 1916, M. sacki (Paramonov, 1936) and M. sophron Hurkmans, 1993 are redefined and redescribed. Following a detailed study of the type material sourced from different entomological collections, the status of all available taxa related to M. serrulatus is revised and a new synonymy is proposed: M. tener Sack, 1913 syn. nov. (junior synonym of M. serrulatus). The identity of M. trizonus (Szilady, 1940) could not be assessed as the type specimens are lost. Thus, the name M. trizonus is considered as nomen dubium. The monophyly and composition of this species group are assessed through Maximum Parsimony and Maximum Likelihood analyses of the mitochondrial COI and nuclear 28S rRNA gene sequences.Peer reviewe

Neotropical Copestylum (Diptera, Syrphidae) breeding in Agavaceae and Cactaceae including seven new species

We studied 42 species of saprophagous, Neotropical Copestylum (Diptera, Syrphidae) reared from decaying Cactaceae and Agavaceae. Thirty-three species were reared during fieldwork in Bolivia, Costa Rica, Ecuador, Mexico, Peru, and Trinidad from 1998–2007. Nine species came from museum and private collections. Seven were new species. We describe these new species and the third stage larva and/or puparium and breeding sites of 40 species. Not described are two apparent species related to Copestylum apicale (Loew, 1866) reared from Cactaceae. Resolution of their status was beyond the scope of this paper but reference is made to their distinctive larval morphology. Based on early stage characters all reared species can be placed in ten species groups, all but three of which have been recognized previously on the basis of adult characters. A high level of congruence was found between adult and larval characters in terms of these species groups. Eight of the groups appear to be related closely and may represent a monophyletic lineage within Copestylum that has diversified in xeric habitats. Early stage morphology varied within and amongst groups but two trends in functional morphology are recognizable. One trend is towards feeding in watery decay and the other towards feeding in firmer decay. The latter trend is characterized by species that scoop food and use grinding mills in their head skeletons to break it up. They also have armoured thoraces with varying arrangements of sclerotized spicules or stiffened setae for gripping and protection during tunnelling, a short anal segment, and a short posterior breathing tube for protecting the openings. The former trend is characterized by species with opposite and contrasting features. They filter food and have well-developed pre-oral setal filters but they lack grinding mills or only have poorly developed grinding mills. They have reduced thoracic armature, elongate anal segments, and posterior breathing tubes which facilitates simultaneous feeding and respiration. Comparison with 23 Copestylum species reared from bromeliads (Bromeliaceae) suggests a common pattern of diversification in that species groups with the largest body sizes are more specialized