Euura leucapsis ( Tischbein, 1846 ), 2014

Liston, Andrew D., Heibo, Erik, Prous, Marko, Vårdal, Hege, Nyman, Tommi & Vikberg, Veli, 2017, North European gall-inducing Euura sawflies (Hymenoptera, Tenthredinidae, Nematinae), Zootaxa 4302 (1), pp. 1-115 : 75-76

Euura leucapsis ( Tischbein, 1846)

Nematus leucapsis Tischbein, 1846: 77 . Described: adult [sex not stated]. Neotype, ♀, designated by Kopelke (2007a), SMF [examined]. Type locality: Germany, Mecklenburg-Vorpommern, Zittwitz.

Phyllocolpa leucapsis: Kopelke (1999) .

Euura leucapsis: Prous et al. (2014) .

Nematus alienatus Förster, 1854a: 334 –335, 338. Described: ♀. Lectotype, ♀, designated by Kopelke (2007a), ZSM [examined]. Type locality: Germany, near Aachen. Syn. nov.

Pontania alienata: Konow (1890) .

Phyllocolpa alienata: Kopelke (2007b) .

Euura alienata: Beneš (2015b) .

Nematus (Pontania) coriaceus Benson, 1953: 150 –151. Described: ♀, ♂. Holotype, ♀, BMNH [not examined]. Type locality: England, Buckinghamshire, Whaddon Chase. Synonymy by Kopelke (2007b), but see also Taeger et al. (2010: 11).

Pontania coriacea: Benson (1958) .

Phyllocolpa coriacea: Benson (1960a) .

Pontania (Phyllocolpa) coriacea: Viitasaari & Vikberg (1985) .

Nematus (Phyllocolpa) coriaceus: Zhelochovtsev (1988) .

Phyllocolpa rolleri Liston, 2005: 183 - 185.: ♀, ♂. Holotype, ♀, SDEI [examined]. Type locality: Slovakia, Lower Tatras , Krakova hol´a. Syn. nov.

Notes on types and taxonomy. Vikberg (2010a) and Beneš (2013) have already discussed the unfortunate decision by Kopelke (2007a) to designate a specimen of this taxon (with sculptured and dull antennal hollows) as neotype of leucapsis . During the preceding decades, nearly all authors (e.g. Benson 1958, 1960, Beneš 1968a, Zhelochovtsev 1988) had interpreted the name leucapsis as denoting a single species (with glabrous and shiny antennal hollows), which Kopelke (2007a) regarded as a group of species including, amongst others, ischnocera , polita and prussica . Although the novel application of the name leucapsis to a species that is not very closely related to those which were previously so named is certain to cause much confusion, the ICZN (1999) does not seem to offer a way of reversing Kopelke's action.

Kopelke (2007b) regarded Phyllocolpa alienata and P. leucapsis as separate species, monophagous respectively on Salix aurita and S. cinerea . The main morphological characters presented in his key to distinguish them were the length: breadth index of valvulae 3 in dorsal view and very slight differences in the profile of valvula 3 in lateral view. The key states that ctenidia are present on the lancet from annulus 3 in both taxa, although his Figure 1 d ( leucapsis ) shows these as present from annulus 2. All these characters are somewhat variable and are not correlated with the host plants. The penis valves are practically indistinguishable, as are Kopelke's drawings of these. On the other hand, specimens from S. aurita tend to be darker than those from S. cinerea . This applies to the coloration of the head, pronotum, femora and cerci, but a complete spectrum of intermediate specimens exists. Possibly the trend is merely a reflection of the generally cooler sites, often in more northern or upland areas, where S. aurita is the main host. Nearly the same applies to Phyllocolpa rolleri , which represents an even darker extreme than P. alienata , on the same continuum of variability. In view of these considerations, and the lack of evidence for a genetic difference, we propose the synonymy of these three taxa.

Blank et al. (2009) followed the error made by Kopelke (2007b: in the text), and treated coriacea (Benson) as a synonym of alienata . However, it was Kopelke's intention to place coriacea as a synonym of leucapsis ( Kopelke 2007b: in the abstract), as noted by Taeger et al. (2010).

Variability. Female: Body length: 3.1–4.1mm. Male: 3.3–3.8mm. See also above (Notes on types and taxonomy). Total number of specimens examined: 21.

Genetic data. COI barcodes of five German leucapsis specimens from S. cinerea and five German and Scottish specimens from S. aurita were identical. The barcodes of E. acutiserra , morphologically the most similar north European species, differ from leucapsis by an approximate minimum of 3.0%.

Bionomics. Host plants: Salix cinerea ( Kopelke 2007b) , S. aurita ( Kopelke 2007b: as alienata ), and S. silesiaca ( Liston 2011: Salix hastata , reported in the original description as the host of rolleri , was a misidentification). A larva collected from S. lapponum by TN (tree: 5x _ Euura _ acutiserra _ Salix _ lapponum ) was identified by its barcode as E. leucapsis . Perhaps this represents a case of oviposition on an atypical host. Biology: Kopelke (2007b).

Distribution. Central and North Europe, north to Finnmark ( Kopelke 2007b), Russian Far East ( Zhelochovtsev & Zinovjev 1995), Canada ( Benson 1962). Occurrence in Sweden: published records; Skåne ( Benander 1966, as Pontania coriacea on S. cinerea and S. aurita ), Halland, Torne Lappmark ( Coulianos & Holmåsen 1991). Material examined: Skåne, Hälsingland.

Figures

FIGURE 1. Phylogenetic tree for European gall-making Euura sawflies, based on two mitochondrial and one nuclear region. The mitochondrial regions used are fragments of cytochrome oxidase subunit I (COI, 810 bp) and cytochrome b (Cytb, 718 bp). The nuclear marker used is a fragment of sodium / potassium-transporting ATPase subunit alpha (NaK, 997 bp). The major gall types are plotted against the sawfly lineages. For clarity, the outgroup taxa Nematus septentrionalis, N. carpini, N. tulunensis, and Mesoneura opaca were excluded from the tree.