Euura amerinae ( Linnaeus, 1758 )

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 : 55-56

Euura amerinae ( Linnaeus, 1758)

Cynips amerinae Linnaeus, 1758: 554 . Described: adult, gall, recorded host: Salix pentandra . Type locality: not stated. Type material thought to be lost or destroyed: not mentioned by Malaise & Benson (1934), Kopelke (1996), or The Linnean Society (2015).

Cryptocampus amerinae: Konow (1890) .

Euura amerinae: Enslin (1915) .

Euura (Euura) amerinae: Viitasaari & Vikberg (1985) .

Nematus (Euura) amerinae: Zhelochovtsev (1988) .

Tenthredo salicispentandrae Retzius, 1783 [mandatory correction of original spelling T. Salicis pentandrae ]: 73. Described by indication on Degeer (1771: 1009, pl. 39; " Fausse chenille dans les galles ligneuses des branches du Saule "). No information is available on the existence of types. Type locality: Sweden.

Tenthredo gallarum Latreille, 1804: 38 –39. Described by indication on Degeer (1771: 1009); see under Tenthredo salicispentandrae .

Tenthredo saliceti Fallén, 1808: 111 –112. Lectotype, ♀, designated by Kopelke (1996), MZLU [not examined]. Type locality: not stated, but can be assumed to be in Sweden. Until Lindqvist (1956), the name saliceti was generally wrongly applied to what is now called E. mucronata (and morphologically similar forms).

Nematus pentandrae Dahlbom, 1835: 28 –29. Described by indication on Degeer 1771; see under Tenthredo salicispentandrae . Authorship of this species name is frequently, but wrongly, attributed to Thomson (1863).

Nematus (Cryptocampus) medullarius Hartig, 1837: 224 –225. Described by indication on Degeer 1771; see Tenthredo salicispentandrae , above.

Nematus (Cryptocampus) populi Hartig, 1837: 223 –224. Described: ♀, ♂, gall, recorded host: "Pappeln" [ Populus ]. Lectotype, ♂, designated by Liston et al. (2006), ZSM [examined]. Type locality: not stated, but probably Germany. Synonymy with E. amerinae by Enslin (1918a) and Liston et al. (2006).

Nematus impunctatus Herrich-Schäffer, 1840: 176 . A new name for "[ Nematus ] intercus Lep. [Lepeletier] [no.] 200". Under the name Nematus intercus Lepeletier (1823) cited the descriptions of " Tenthredo salicis pentandrae De Vill. , no. 88" and "DeG., no. 24, Tab. 39, fig. 9 et 10" and concluded his description of syntype females collected near Paris [probably lost], with the remark that his Nematus intercus is not the same as Tenthredo intercus Linnaeus, 1758 [probably not a symphytan]. These indications clearly refer to Euura amerinae . Was previously treated as a synonym of E. viminalis (L.) ( Taeger et al. 2010). Syn. nov.

Nematus buccatus Thomson, 1863: 639 . Described: ♀, ♂; syntypes should be in MZLU [not examined]. Type locality: Dalarna and Småland. Synonymy with amerinae following Dalla Torre (1894).

Pontania joergenseni Strand, 1908 [mandatory correction of incorrect original spelling jörgenseni]: 158. Described by indication on Jörgensen (1906b); syntypes should be in ZMUC, but could not be found. Type locality: Denmark, Sønderby. Synonymy with amerinae by Blank et al. (2009).

Variability. Female: Body length: 3.5–5.1mm. Upper rear pronotum pale marked to completely black. Lateral vertex pale marked to completely black. Tergum 10 extensively pale to completely black. Male: 3.8–6.0mm. Supraclypeal area mostly pale to mostly black. Upper rear pronotum pale marked to completely black. The darkest specimens examined are from Norway (Nordland), the palest from Germany. Total number of specimens examined: 20.

Genetic data. The closest barcodes to those of E. amerinae in BOLD are of E. testaceipes (diverging by a minimum of approx. 1.1%) and E. venusta (approx. 2.8%).

Similar species. Females of E. venusta and E. testaceipes are separable from amerinae by several characters (see Key). Males of both the former species are apparently rare, compared to amerinae , with a more normal sexratio. Male amerinae are best recognised by the short and wide inner tooth of the claw, which is longer and thinner in all other W. Palaearctic species in the group.

Bionomics. Host plants: Salix pentandra ( Kopelke 1996) . The host recorded for N. populi by Hartig (1837) is certainly a misidentification of S. pentandra (Liston et al. 2006) , but there are unconfirmed observations of galls on other Populus species (see, e.g., Baer 1910). Biology: Kolehmainen et al. (1994), Kopelke et al. (2012), Liston (1982, 2003), Roininen et al. (1993a), Roininen et al. (1996). This is the only European gall-inducing sawfly, apart from E. piliserra , in which several larvae normally inhabit a single gall.

Distribution. North and Central Europe, including the British Isles (Taeger et al. 2006), to the northern parts of the Russian Far East ( Zhelochovtsev & Zinovjev 1995). Occurrence in Sweden: published records; Skåne ( Wahlgren 1944), Halland ( Andersson 1955), Småland, Öland, Gotland (Wahlberg 1951), Västergötland ( Lundberg 1963), Bohuslän, Södermanland (Wahlberg 1951), Uppland ( Wahlgren 1944, 1953), Värmland, Dalarna, Norrbotten, Torne Lappmark (Wahlberg 1951). Material examined: Skåne, Småland, Öland, Norrbotten.