The Mycetophila ruficollis Meigen (Diptera, Mycetophilidae) group in Europe: elucidating species delimitation with COI and ITS2 sequence data

Abstract

European species of the Mycetophila ruficollis group are compared on the basis of morphology and sequences of mitochondrial cytochrome oxidase subunit one (COI) and the ITS2 region of nuclear ribosomal DNA. The study represents the first evaluation of morphology-based species delimitation of closely related fungus gnat species by applying molecular information. Detailed descriptions and illustrations of the male terminalia are presented along with a key for the identification of all nine European species of the group. Phylogenetic analyses of molecular data generally supported the morphological species discrimination. The barcoding region of COI superseded ITS2 rDNA in resolving species. In the COI barcoding region interspecific differences ranged from 2.9 to 10.6% and the intraspecific distance from 0.08 to 0.8%. Only COI data distinguished between the similar and closely related Mycetophila ichneumonea and Mycetophila uninotata of which the latter was observed to include cryptic species. The host range of some species is suggested to be narrower than previously considered and to depend on the forest type. Presented evidence indicates the importance of analysing sequence data of morphologically very similar mycetophages reared from identified host fungi for elucidating species delimitation as well as their geographic and host ranges. New country records, viz. Estonia for Mycetophila evanida, Georgia for Mycetophila ichneumonea, Mycetophila idonea and Mycetophila ruficollis, and Norway for Mycetophila strobli, widen the known distribution ranges of these species.

Six new species of Afrotropical Allodia (Diptera: Mycetophilidae): DNA barcodes indicate recent diversification with a single origin

“…The genetic difference between members of the different species ranged from 5.6% to 10.1%, which supports the morphological species delimitation. Our species delimitation based on genetic distances is in accordance with what is seen in other closely related species of Mycetophilidae (Jürgenstein et al 2015;. Due to small sample size of A. jaschhofi, A. keurbosensis and A. drakensbergensis, and that all individuals of A. nyeriensis were collected at the same time at the same locality, the intraspecific distances could not be calculated.…”

“…CO1 is the standard DNA barcode region for animals (Hebert et al 2003), and has previously been successful in separating closely related species in Mycetophilidae (e.g. Ševčík et al 2016;Jürgenstein et al 2015).…”

Remarkable fly (Diptera) diversity in a patch of Costa Rican cloud forest: Why inventory is a vital science

“…Morphological studies are far more informative in understanding diversity than a species known only as a number. Barcoding, of course, is a powerful and useful tool in aiding species identity (including for inventories) and association of sexes and poorly known immatures with adults but we see it as just one useful instrument in a much larger toolbox (e.g., Dénes et al 2016;Germann et al 2010;Heller & Rulik 2016;Jürgenstein et al 2015;Kehlmaier & Assmann 2008;Petersen et al 2007;Salmela et al 2014;Ståhls & Haarto 2014;Stur & Borkent 2014;Stur & Ekrem 2015;Willassen 2005). Barcode clusters are hypotheses of species identity that need to be confirmed by taxonomists working with more complete sets of evidence.…”

A new species of Docosia Winnertz from Central Europe, with DNA barcoding based on four gene markers (Diptera, Mycetophilidae)

“…Bourke et al 2013, Lv et al 2014, Schwarzfeld and Sperling 2014). Concerning fungus gnats, comparisons between COI and ITS2 were recently provided by Jürgenstein et al (2015) and Kurina et al (2015). They both came to the conclusion that COI performed better.…”