Pristiphora confusa Lindqvist, 1955

Prous, Marko, Vikberg, Veli, Liston, Andrew & Kramp, Katja, 2016, North-Western Palaearctic species of the Pristiphora ruficornis group (Hymenoptera, Tenthredinidae), Journal of Hymenoptera Research 51, pp. 1-54 : 23

Pristiphora confusa Lindqvist, 1955

Pristiphora confusa Lindqvist, 1955: 40-41. Holotype ♀ (http://id.luomus.fi/GL.5209) in MZH, examined. Type locality: Sipoo [Sibbo], Uusimaa, Finland.

Similar species.

Based on the external morphology, the most similar species are P. albitibia , P. armata , P. leucopus , P. opaca , P. pusilla , P. sootryeni , and P. subopaca . The species is best distinguished through the structure of male penis valve (Figs 89-90 ). Unfortunately, it is rather difficult to distinguish females from P. armata , P. leucopus , P. opaca , and P. subopaca , as the differences in lancets are small (Figs 54-57 , 62 - 69 ). Apical serrulae are more protruding and shorter than in P. opaca and P. subopaca (Figs 62 - 69 ). Pristiphora opaca also has a fold at the base of tangium of the lancet (Figs 64-65 ) that is lacking in other species in the Pristiphora ruficornis group. Pristiphora opaca tends also to have a smaller subapical tooth than P. confusa . The pterostigma of P. confusa is apically brown and basally dark brown, like in P. opaca (Fig. 28 ), but unlike in P. subopaca , in which it is uniformly yellow (Fig. 27 ). In P. armata and P. leucopus , the pterostigma is usually dark brown (Fig. 29 ), but sometimes the pterostigma can have more or less the same colour as in P. confusa . In this case, small differences in the lancet can help distinguish P. confusa from P. armata and P. leucopus , as ctenidia tend to be more distinct in P. confusa (Figs 54-57 , 62-63 ). Among the males, the most similar penis valves are of P. subopaca . The ventro-apical spine in P. confusa is barely bent and the pseudoceps is narrower compared to P. subopaca (Figs 89-92 ).

Genetic data.

Based on COI barcode sequences, P. confusa belongs to the same BIN cluster (BOLD:AAG3568) as P. aphantoneura , P. bifida , P. luteipes , P. opaca , P. pusilla , P. staudingeri , and P. subopaca (Fig. 1 ). The nearest neighbour (BOLD:AAQ2302, P. armata and P. leucopus ) is 2.76% different. Two available TPI sequences (one male and one heterozygous female) group weakly together and can be distinguished from other species (Fig. 2 ).

Host plants.

Salix caprea L. ( Kangas 1985), Salix fragilis L. ( Benson 1958), Salix phylicifolia L. ( Benson 1958).

Distribution and material examined.

Western Palaearctic. Specimens studied are from Estonia, Finland, France, Germany, Sweden, and Switzerland.

Figures

Figure 1. Maximum likelihood tree of Pristiphora ruficornis group based on cytochrome oxidase subunit I (COI) sequences (1078 bp). Specimens that had at least the full barcode sequence (658 bp) were included in the analysis. Branches with multiple specimen identification labels represent identical sequences, only one of which was used in the analysis. Numbers on the nodes show approximate likelihood-ratio test (aLRT) support values and bootstrap proportions (%, BP). Support values for weakly supported branches (aLRT <0.9 and / or BP <70) are not shown. The inset shows the tree with outgroup species. The scale bar shows the number of estimated substitutions per nucleotide position. An asterisk (*) indicates the specimens that we have not studied. AUT, Austria; CAN, Canada; CHN, China; DEU, Germany; ESP, Spain; EST, Estonia; FIN, Finland; FRA, France; GBR, United Kingdom; ITA, Italy; MAR, Morocco; NOR, Norway; PRT, Portugal; SWE, Sweden; USA, United States of America. NUMTs?, possible nuclear mitochondrial pseudogenes.

Figure 2. Maximum likelihood tree of Pristiphora ruficornis group based on triose-phosphate isomerase (TPI) sequences (alignment length 842 bp). Branches with multiple specimen identification labels represent identical sequences, only one of which was used in the analysis. Numbers on the nodes show approximate likelihood-ratio test (aLRT) support values and bootstrap proportions (%, BP). Support values for weakly supported branches (aLRT <0.9 and / or BP <70) are not shown. The scale bar shows the number of estimated substitutions per nucleotide position.

Figures 87 - 96. Penis valves of Pristiphora ruficornis group. 87 P. bifida DEI-GISHym 80000 (arrow indicates a dorsal depression of the pseudoceps) 88 P. frigida NHRS-HEVA 000003861 (arrow indicates a membranous fold near the tip of the ventro-apical spine) 89 P. confusa DEI-GISHym 31265 90 P. confusa PR. 460 VV 91 P. subopaca DEI-GISHym 80030, left penis valve 92 P. subopaca paratype http: // id. luomus. fi / GL. 5203 93 P. pusilla DEI-GISHym 80029, left penis valve with strong dorsal depression of the pseudoceps (arrow) 94 P. pusilla DEI-GISHym 80029, right penis valve with weak dorsal depression of the pseudoceps 95 P. opaca PR. 459 VV 96 P. opaca http: // id. luomus. fi / GL. 5206, paratype of P. amaura Lindqvist.

Figures 54 - 57. Lancets of Pristiphora armata subgroup. 54 P. leucopus PR. 393 VV, summer morph 55 P. leucopus PR. 467 VV reared ex larva from Tilia sp. 56 Nematus armatus Thomson syntype specimen 8 (X 112) 57 P. armata DEI-GISHym 20366.

Figures 62 - 65. Lancets of Pristiphora aphantoneura subgroup. 62 P. confusa holotype 63 P. confusa PR. 544 VV reared ex larva from Salix caprea 64 P. opaca DEI-GISHym 80032 (presence of a fold is indicated by an arrow) 65 P. opaca PR. 389 VV.

Figures 66 - 69. Lancets of Pristiphora subopaca. 66 PR. 403 VV 67 P. subopaca holotype 68 P. coniceps holotype 69 P. brunniapex holotype.

Figures 18 - 36. 18 P. albitibia DEI-GISHym 31514, thorax in lateral view 19 P. luteipes DEI-GISHym 80038, thorax in lateral view 20 P. astragali holotype, thorax in lateral view 21 P. leucopus DEI-GISHym 31556, lateral 22 P. leucopus DEI-GISHym 4989, lateral 23 P. luteipes DEI-GISHym 80038, lateral 24 P. luteipes DEI-GISHym 80038, flagellum 25 P. ruficornis DEI-GISHym 31185, flagellum 26 P. armata DEI-GISHym 11092 27 P. subopaca holotype, pterostigma (arrow) 28 P. opaca holotype, pterostigma (arrow) 29 P. ruficornis DEI-GISHym 31185, pterostigma (arrow) 30 P. appendiculata DEI-GISHym 31500, claw 31 P. opaca holotype, claw 32 P. subopaca holotype, claw 33 P. armata DEI-GISHym 11554, claw 34 P. bifida DEI-GISHym 31507, claw 35 P. frigida NHRS-HEVA 000005006, flagellum with barely visible stout black setae (arrows) 36 P. pusilla DEI-GISHym 80050, flagellum with clearly visible stout black setae.