Paraphyly and low levels of genetic divergence in morphologically distinct taxa: revision of the Pseudoanthidium scapulare complex of carder bees (Apoidea: Megachilidae: Anthidiini)

Abstract

The Palaearctic complex of anthidiine bees closely related to Pseudoanthidium scapulare has long been a source of unresolved taxonomic and systematic issues. Until now, the number of species in the complex and their geographical distributions were largely unclear, thus complicating the compilation of accurate species checklists and hindering conservation efforts. In order to address these issues, we use morphology and mitochondrial cytochrome c oxidase subunit I (COI) sequences, combined with a thorough examination of the relevant literature and type material, to delimit species within this complex, assign names to species and clarify geographical ranges. An unexpected result was that a certain number of morphologically distinct taxa exhibited low levels of genetic divergence at the COI locus, resulting in species paraphyly. A set of ultra-conserved elements (UCEs) was also sequenced in order to further investigate relationships among these taxa. One morphologically distinct species was also paraphyletic using UCE data, hinting at recent species divergences and genetic exchange at zones of contact between morphologically well-differentiated taxa. The results of our study reveal the presence of ten species in this complex, including a previously overlooked species for western continental Europe. A complete diagnosis of the males and females of these species is provided, as are maps detailing the geographic distributions of each. An illustrated identification key to the males and females of each species is presented. Two new species are described, Pseudoanthidium kaspareki sp. nov. and P. rozeni sp. nov. New synonymy is established for several species and Pseudoanthidium palestinicum and P. tropicum are raised to species level. The new combination, Icteranthidium floripetum comb. nov. is also established. Lectotypes are designated for the following species: Anthidium eversmanni, A. floripetum, A. frontale, A. karakalense, A. nanum and A. reptans. Previously unpublished lectotype designations are published here for A. sinuatum and A. tenellum.

Unexpected levels of cryptic diversity in European bees of the genus Andrena subgenus Taeniandrena (Hymenoptera, Andrenidae): implications for conservation

“…These recent updates in northern or central European countries, characterised by well-known faunas that are studied by numerous active bee specialists, give a worrisome hint at the huge taxonomic work necessary in southern European countries, which have rich but poorly investigated bee faunas. In agreement with this suspicion, is that numerous bee species have recently been described from Southern Europe (e.g., Müller 2012;Pauly et al 2015;Wood and Cross 2017;Kasparek 2020;Wood et al 2020Wood et al , 2021Litman et al 2021;Wood 2021Wood , 2022, and many more will undoubtedly be described in the near future.…”

“…Obtaining accurate taxonomic and distribution information on bees is crucial for the conservation and monitoring of native pollinators. However, new species are regularly uncovered even in regions with a long tradition in taxonomy such as northern and central Europe, following changes in taxonomy (e. g., Straka and Bogusch 2011;Pauly et al 2019;Le Divelec 2020;Litman et al 2021), the discovery of hitherto undetected taxa due to challenging identifications (e. g., Notton and Norman 2017;Falk et al 2019), inventories in poorly sampled habitats (Johansson and Paukkunen 2017;Schmid-Egger et al 2021), range expansions (Notton et al 2016;Saure and Petrischak 2020), or the description of new species (e. g., Pauly et al 2015;Praz et al 2019). These recent updates in northern or central European countries, characterised by well-known faunas that are studied by numerous active bee specialists, give a worrisome hint at the huge taxonomic work necessary in southern European countries, which have rich but poorly investigated bee faunas.…”

Nest structure, associated parasites and morphology of mature larvae of two European species of Pseudoanthidium Friese, 1898 (Hymenoptera, Megachilidae)

“…The bee genus Pseudoanthidium Friese is a genus of small bees in the tribe Anthidiini, family Megachilidae, comprising 64 species worldwide (Michener 2007). This genus is divided into 12 subgenera, of which the subgenus Pseudoanthidium has the most species (Litman et al 2016(Litman et al , 2021. In total, around 20 species are known from the western part of the Palaearctic biogeographic region, including nine species that occur in Europe (Kuhlmann et al 2021;Litman et al 2021).…”

“…This genus is divided into 12 subgenera, of which the subgenus Pseudoanthidium has the most species (Litman et al 2016(Litman et al , 2021. In total, around 20 species are known from the western part of the Palaearctic biogeographic region, including nine species that occur in Europe (Kuhlmann et al 2021;Litman et al 2021). Of these nine species, Pseudoanthidium nanum Mocsary (syn.…”

“…Of these nine species, Pseudoanthidium nanum Mocsary (syn. P. lituratum (Panzer)) is the most widespread, occurring in southern and central Europe, Russia and the Middle East (Banaszak and Romasenko 1998;Westrich 2018;Lhomme et al 2020;Kuhlmann et al 2021;Litman et al 2021), and was recently introduced into several parts of the USA (Portman et al 2019). This species prefers steppic formations and similar open habitats (Macek et al 2010;Westrich 2018).…”