Jelena Ačanski

Systematics and taxonomy of the ruficornis group of genus Merodon Meigen (Diptera: Syrphidae)

We revise the ruficornis group of species of Merodon Meigen (Diptera, Syrphidae) providing an illustrated key, a discussion of taxonomic characters and a morphological diagnosis. A total of 18 species from the ruficornis group are treated including distributional data. Descriptions are provided for seven new species: M. gallicus Vujić & Radenkovićsp.n., M. hoplitis Hurkmans sp.n., M. lamellatus Vujić & Radenkovićsp.n., M. nigripodus Vujić & Hayat sp.n., M. ovaloides Vujić & Radenkovićsp.n., M. ponticus Vujić & Radenkovićsp.n., and M. turcicus Vujić & Hayat sp.n. The taxon M. auripes Sack, is redefined and a neotype designated. Lectotypes are designated for M. graecus Loew; M. planiceps Loew and M. crymensis Paramonov. The monophyly and systematic position of this species group was assessed based on parsimony and maximum likelihood analyses of mitochondrial COI and nuclear 28S rDNA sequences. A very high level of endemism was observed in the ruficornis species group. Among 18 taxa, 12 are limited‐range endemics, present in few mountain areas or in a small part of the total range of the group. These endemics clearly show the importance of geographic isolation in the process of speciation.

Systematics of Pipizini and taxonomy of European Pipiza Fallen: molecular and morphological evidence (Diptera, Syrphidae)

Vujić, A., Ståhls, G., Ačanski, J., Bartsch, H., Bygebjerg, R. & Stefanović, A. (2013). Systematics of Pipizini and taxonomy of European Pipiza Fallén: molecular and morphological evidence (Diptera, Syrphidae). —Zoologica Scripta, 42, 288–305.

Molecular and Morphological Inference of Three Cryptic Species within the Merodon aureus Species Group (Diptera: Syrphidae).

The Merodon aureus species group (Diptera: Syrphidae: Eristalinae) comprises a number of different sub-groups and species complexes. In this study we focus on resolving the taxonomic status of the entity previously identified as M. cinereus B, here identified as M. atratus species complex. We used an integrative approach based on morphological descriptions, combined with supporting characters that were obtained from molecular analyses of the mitochondrial cytochrome c oxidase I gene as well as from geometric morphometry of wing and surstylus shapes and environmental niche comparisons. All applied data and methods distinguished and supported three morphologically cryptic species: M. atratus stat. nov., M. virgatus sp. nov. and M. balkanicus sp. nov., which constitute the M. atratus species complex. We present an identification key for the sub-groups and species complexes of the M. aureus species group occurring in Europe, describe the taxa and discuss the utility of the applied methods for species delimitation. The estimated divergence times for the species splits of these taxa coincide with the Pleistocene Günz-Mindel interglaciation and the Great interglaciation (between the Ris and Mindel glacial periods).

Revision of the species of the Merodon nanus group (Diptera: Syrphidae) including three new species

The nanus group of the genus Merodon Meigen (Diptera, Syrphidae) is revised, yielding an illustrated key, a discussion of taxonomic characters and morphological diagnosis for the five species of this group. Three new cryptic species are described, Merodon kopensis Vujić et Hayat sp. n., M. neonanus Vujić et Taylor sp. n. and M. rasicus Vujić et Radenković sp. n. New diagnostic characters are given for M. nanus Sack and M. telmateia Hurkmans. In addition, environmental profiles for each investigated species have been defined and compared, and maps of distribution and richness created. Niche dissimilarity was found for each species. Eastern Anatolia and the southern Aegean region of Turkey are reported as the most species rich regions for the nanus group.

Phylogeographic patterns of Merodon hoverflies in the Eastern Mediterranean region: revealing connections and barriers

Abstract We investigated the phylogeographic patterns of Merodon species (Diptera, Syrphidae) in the Eastern Mediterranean. Ten species were sampled on five different islands and mainland sites as a minimum. All samples were screened for their mtDNA COI barcode haplotype diversity, and for some samples, we additionally generated genomic fingerprints. The recently established zoogeographic distribution categories classify these species as having (1) Balkan distribution; (2) Anatolian distribution; (3) continental areas and large islands distribution; and (4) with wide distribution. The ancestral haplotypes and their geographical localities were estimated with statistical parsimony (TCS). TCS networks identified as the ancestral haplotype samples that originated from localities situated within the distributional category of the species in question. Strong geographical haplotype structuring was detected for many Merodon species. We were particularly interested to test the relative importance of current (Aegean Sea) and past Mid‐Aegean Trench) barriers to dispersal for Merodon flies in the Aegean. We employed phylogenetic β‐diversity (Pβ total) and its partition in replacement (Pβ repl) and richness difference (Pβ rich) to test the importance of each explanatory variable (interisland distance, MAT, and island area) in interisland differences using partial Mantel tests and hierarchical partitioning of variation. β‐Analyses confirmed the importance of both current and past barriers to dispersal on the evolution of group. Current interisland distance was particularly important to explain the replacement of haplotypes, while the MAT was driving differences in richness of haplotypes, revealing the MAT as a strong past barrier whose effects are still visible today in the phylogenetic history of the clade in the Aegean. These results support the hypothesis of a highly restricted dispersal and gene flow among Merodon populations between islands since late Pleistocene. Additionally, patterns of phylogeographic structure deduced from haplotype connections and ISSR genome fingerprinting data revealed a few putative cases of human‐mediated transfers of Merodon spp.

Image Processing Method for Automatic Discrimination of Hoverfly Species

An approach to automatic hoverfly species discrimination based on detection and extraction of vein junctions in wing venation patterns of insects is presented in the paper. The dataset used in our experiments consists of high resolution microscopic wing images of several hoverfly species collected over a relatively long period of time at different geographic locations. Junctions are detected using the combination of the well known HOG (histograms of oriented gradients) and the robust version of recently proposed CLBP (complete local binary pattern). These features are used to train an SVM classifier to detect junctions in wing images. Once the junctions are identified they are used to extract statistics characterizing the constellations of these points. Such simple features can be used to automatically discriminate four selected hoverfly species with polynomial kernel SVM and achieve high classification accuracy.

Review of the Merodon albifasciatus Macquart species complex (Diptera: Syrphidae): the nomenclatural type located and its provenance discussed

The Palaearctic Merodon geniculatus species group (Diptera, Syrphidae: Merodontini) currently comprises six Western Mediterranean species and four species with Eastern Mediterranean distribution. One of this group species, Merodon albifasciatus Macquart, 1842, is the only Merodon species listed from the Oriental Region. We discovered the lost holotype, which fit morphologically with European Merodon females of the M. albifasciatus species complex confirmed here and that occurs in the Palaearctic region. An integrative approach to the taxonomy of M. albifasciatus based on morphological and molecular evidences revealed the existence of two additional closely-related species in the Eastern Mediterranean area, M. luteofasciatus Vujić, Radenković Ståhls sp. nov. and M. neofasciatus Ståhls Vujić sp. nov.. The females of these three species can only be separated by molecular and distributional data. With the aim of stabilising species concepts within the complex, the taxon distributed in mainland Greece, including the Peloponnese was associated to the old female holotype of M. albifasciatus. The identity of Merodon fractipes Paramonov, described from Rhodes Island (Greece) as subspecies of M. geniculatus Strobl in Czerny Strobl, could not be resolved as the type specimen is lost. Thus the name M. fractipes is suppressed as nomen dubium. We discuss the distribution of the species of M. albifasciatus complex, identify host plants of M. neofasciatus, and provide an identification key to males of Eastern Mediterranean species of Merodon geniculatus group.

An integrative approach in the assessment of species delimitation and structure of the Merodon nanus species group (Diptera: Syrphidae)

The Merodon nanus group (Diptera, Syrphidae) is a small group of closely related species with high morphological similarity. Until now, based on morphological characters, this group consisted of five species: M. nanus Sack, 1931; M. telmateia Hurkmans, 1987; M. kopensis Vujić et Hayat, 2015; M. neonanus Vujić et Taylor, 2015; and M. rasicus Vujić et Radenković, 2015. Here, using an integrative approach based on molecular characters (sequences of the D2–3 region of the nuclear 28S rRNA gene and the mitochondrial COI gene) and data obtained from geometric morphometry of wing shape, we distinguish all five previously morphologically defined species of the group. Additionally, we identify one species as being new to science, M. vladimiri Vujić et Kočiš Tubić sp. n. We emphasize the separation of this newly described species according to the sequences obtained from the slowly evolving 28S rRNA gene, which demonstrated four to five mutation positions between this species and morphologically the most similar M. neonanus species. Also, our results show a clear division of M. telmateia into at least three population groups that we designate as the subspecies: M. telmateia mediterraneus Ačanski et Kočiš Tubić subsp. n. and M. telmateia samosensis Ačanski et Kočiš Tubić subsp. n. exhibiting western distributions (western Anatolia and the Greek island of Samos, respectively) and the nominative subspecies M. telmateia telmateia with an eastern Anatolian distribution.

Environmental niche divergence of species from Merodon ruficornis group (Diptera: Syrphidae)

In this paper we analyzed environmental differentiation of closely related species from the Merodon ruficornis group. By applying principal component analysis (PCA) and environmental niche modelling (ENM)-based techniques, we estimated the level of niche divergence of closely related species. Our results indicate that ecology has an important role in the diversification process in related species from the M. ruficornis group. Distribution patterns of all analyzed species are mainly affected by the limiting effects of the temperature of the coldest quarter and month, as well as by the precipitation of the wettest and driest quarters. Our results demonstrated that among all related species, with the exception of M. ovaloides , overall or partial divergence in environmental space is present. Importantly, the results indicate that the environmental niches of all endemic species are restricted to smaller parts of the environmental space. In the case of niche overlap, the niches of endemic species are placed along the border of the realized niche of the widespread related species. For species in which distribution is not limited by geographical barriers, environmental preferences could be considered as limiting factors for further expansion, as in the case of M. alexandri , a lowland species with very strict climatic adaptations. Knowledge about the environmental factors that might influence the diversification process can provide an explanation for the high diversity in other Merodon species groups. https://doi.org/10.2298/ABS160303095A Received: March 3, 2016; Revised: April 8, 2016; Accepted: May 10, 2016; Published online: October 17, 2016 How to cite this article: Acanski J, Milicic M, Likov L, Milic D, Radenkovic S, Vujic A. Environmental niche divergence of species from Merodon ruficornis group (Diptera: Syrphidae). Arch Biol Sci. 2017;69(2):247-59.