In this paper a previously unknown species of the genus Dahlica Enderlein, 1912, from the subgenus Postsolenobia Meier, 1957, is described as Dahlica (Postsolenobia) weidlichi sp. nov. and compared with the already known species of this subgenus. Analysis of DNA barcodes for all five validly described taxa of the subgenus Postsolenobia show an unexpected pattern of genetic diversity. Careful re-examination of morphological traits fully supports this pattern and leads to the description of a new species. In addition, the habitat of the new species is characterised and the entire distribution of the subgenus is discussed.

In dieser Arbeit wird eine bisher unbekannte Art der Gattung Dahlica Enderlein, 1912, aus der Untergattung Postsolenobia Meier, 1957, als Dahlica (Postsolenobia) weidlichi sp. nov. beschrieben und mit den bereits bekannten Arten dieser Untergattung verglichen. Die Analyse der DNA-Barcodes aller fünf beschriebenen Taxa aus der Untergattung Postsolenobia zeigte ein unerwartetes Muster genetischer Vielfalt. Eine sorgfältige erneute Untersuchung der morphologischen Merkmale unterstützte dieses Muster und führte zur Beschreibung der neuen Art. Darüber hinaus wird der Lebensraum der neuen Art vorgestellt und die gesamte Verbreitung der Untergattung Postsolenobia diskutiert.

For years Michael Weidlich and I have known about a population of small psychids belonging to the subfamily Naryciinae, whose larval cases (bags) apparently belong to an undescribed species of the subgenus Postsolenobia Meier, 1957, in the genus Dahlica Enderlein, 1912.

Numerous adult males were found while working at the Psychidae collection of the Museum Witt Munich among the unsorted material which was collected in 1975 by Herbert Meier (Witt 1980) in Northern Hungary. Several more specimens, which apparently also belong to this new species, were detected by the author among the psychid collection of the SMNK (Arnscheid 2019), also collected by Meier and erroneously sorted by Leo Sieder (Arnscheid 1993) as belonging to other species of the genus. However, both the cases and the females were missing from the series but both are undoubtedly of high relevance for a correct taxonomic classification.

On his research trip to diverse biotopes on the Balkan Peninsula in 2019, Michael Weidlich again searched for fresh material at the locality for this cryptic species. He again found several larval cases and for the first time one male and one female emerged. This confirmed the identity of males from the Museum Witt's collection and the collection of SMNK as belonging to the same still undescribed species as well as their presumed membership of the subgenus Postsolenobia. In addition, it was possible to achieve a complete sequencing of the DNA barcode of the male within the framework of the BOLD project, whereby a comparison of the relationship to the previously known species of the subgenus Postsolenobia became possible, since a number of sequences of other taxa are already available in the mentioned database.

The new species is described below as Dahlica (Postsolenobia) weidlichi sp. nov. The holotype was selected from the specimens collected by Meier and is deposited in the Psychidae collection of the SMNK.

Images of male genitalia (procedure as described in Arnscheid and Weidlich 2017) were taken with an Olympus OMD EM10 Mark II digital camera using an Olympus stereomicroscope with photo adapter and stacked with Combine ZP using Soft Stack; sharpened and de-noised with Neat Image V8 and post-processed with PhotoScape V.37. Images of the holotype were taken with an Olympus E1 digital camera with a 35–50 mm macro lens and a series of 12 single shots stacked with Combine ZP using Soft Stack; sharpened and de-noised with Neat Image V8.

DNA barcode sequences are based on a 658 base-pair long segment of the mitochondrial COI gene (cytochrome c oxidase 1). DNA samples of the new species (dried legs) were prepared and successfully processed at the Canadian Centre for DNA Barcoding (CCDB, Biodiversity Institute of Ontario, University of Guelph) to obtain DNA barcodes using the standard high-throughput protocol described in deWaard et al. (2008), supplemented by public sequences available from BOLD. Further details including complete voucher data and images of the other already in BOLD available species can be accessed in the public dataset “Psychidae of East- and South Europe (POESE)" in the Barcode of Life Data Systems (BOLD; Ratnasingham and Hebert 2007). Percentages of interspecific variation of DNA barcode fragments were calculated under the Kimura 2 parameter model of nucleotide substitution using analytical tools of BOLD systems v. 4.0. (http://www.boldsystems.org). A Neighbor-Joining tree of DNA barcode data was constructed using MEGA 7 under the Kimura 2 parameter model for nucleotide substitutions.

The terminology in the description of the morphology of the species as well as the genitalia follows Arnscheid and Weidlich (2017). The classification of wing scales refers to Sauter (1956). Classification of the venation follows Comstock (1918). The calculation of the genital index according to Sauter (1956) is phallus length / valvae length.

The subgenus Postsolenobia is characterised as follows. Small psychids, male wingspan 8–11 mm, distinguished by the hindwing venation, with only five veins arising from discal cell; M2 and M3 mostly coalescent, but this feature is certainly not constant and M2 and M3 can also be long-stalked in several cases. Venation on forewing with eight veins from discal cell, accessory and intercalary cell absent. Forewing scales broad (classes 5–6) but also transitions to other subgenera exist. Postsolenobia was erected by Meier (1958) originally as a subgenus of Dahlica to which it is very closely related. The taxonomic status was considered uncertain (De Freina and Witt 1985; Arnscheid 1988; Sauter and Hättenschwiler 1999) because the morphological and phenological characters used to separate this subgenus are variable and transitions to related subgenera occur. At least D. karatyshica Rutjan (2000) and D. rakosyi Weidlich (2005) occupy rather transitional positions between subgenera Postsolenobia and Dahlica. Hence, Arnscheid and Weidlich (2017) treated Postsolenobia as a subgenus of Dahlica as it was originally when erected by Meier (1958). Closely examination of the new species reveals it represents the typical morphological features of the subgenus. This is also supported by the molecular data (Tab. 2, Fig. 4).

Figure 6. 

Distribution of the three Dahlica (Postsolenobia) species in South-East Europe. Map created with SimpleMappr (www.simplemappr.net).

I would like to thank my friends Dr. Peter H. Roos (Sprockhövel, Germany) and Dr. Michael Weidlich (Neißemünde, Germany) for critical comments and discussion. My special thanks goes to Debbie Matthews, Gainesville (Florida, USA) for her critical remarks and for the linguistic correction of the English text.