Pristiphora pusilla Malaise, 1921

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 : 30-31

Pristiphora pusilla Malaise, 1921

Pristiphora pusilla Malaise, 1921: 11-12. Lectotype ♂ (NHRS-HEVA000004942; here designated) in NHRS, examined. Type locality: Torne Träsk, Torne Lapp mark, Sweden. Note. In the original description, Malaise (1921) mentioned one female and three males collected from Torne Träsk, but only three specimens (a female and two males) probably belonging to the syntype series were found in NHRS. Among these three specimens, only the female carries the labels “Typus” and " Pristiphora pusilla n. sp." in addition to a locality label "Torne Tr. Malaise ", the two males having originally only the identical locality label "Torne Tr. Malaise " (both males have in addition the label " Pristiphora pusilla Mal. Det: A. Haris 2003" and one of them also apparently relatively recent hand written label "Prist. Pristiphora pusilla "). According to Hege Vårdal (NHRS) there were no other males from Torne Träsk among P. pusilla in the collection and therefore we consider these males as part of the syntype series. Because the female specimen turned out to belong to P. staudingeri (Ruthe, 1859) and in order to preserve the concept of P. pusilla as established by Lindqvist (1953) (who also examined one of the male syntypes), and because separation of males from similar species is more reliable thanks to distinct penis valves, we decided to select one of the males as the lectotype.

Pristiphora amaura Lindqvist, 1955: 43-45. Holotype ♀ (http://id.luomus.fi/GL.5205) in MZH, examined. Type locality: Kangasala, Pirkanmaa, Finland. Note. The male paratype of P. amaura (http://id.luomus.fi/GL.5206) (Fig. 96 ) was misidentified and belongs to P. opaca Lindqvist, 1955 instead.

Similar species.

Based on the external morphology, the most similar species are P. albitibia , P. astragali , P. confusa , P. opaca , P. sootryeni , P. staudingeri , and P. subopaca . The species is best distinguished through the structure of male penis valve (Figs 93-94 ) and female lancet (Fig. 72 ). In females, the lack of small spiny pectines (or dentes semicirculares) on the inner surface of the lancet and weakly developed ctenidia, distinguish it from other similar species. Male penis valves are asymmetric (confirmed for six specimens), the left one (Fig. 93 ) having a noticeably stronger dorsal depression in the middle of pseudoceps and a more strongly bent ventro-apical spine than the right one (Fig. 94 ). The most similar penis valves are those of P. subopaca (Figs 91-92 ), which have a less distinct dorsal depression in the middle of pseudoceps and a less strongly bent ventro-apical spine, but this difference is clear only when compared to the left penis valve of P. pusilla . Externally, P. pusilla might be distinguished from P. subopaca by having ventrally paler antennae (uniformly black in P. subopaca ; Fig. 24 ), which is more evident in males (Fig. 36 ).

Genetic data.

Based on COI barcode sequences, P. pusilla belongs to the same BIN cluster (BOLD:AAG3568) as P. aphantoneura , P. bifida , P. confusa , P. opaca , P. staudingeri , and P. subopaca (Fig. 1 ). The nearest neighbour (BOLD:AAQ2302, P. armata and P. leucopus ) is 2.76% different. Two available nuclear TPI sequences are identical and distinguishable from other species (Fig. 2 ).

Host plants.

Unknown.

Distribution and material examined.

Western Palaearctic. Specimens studied are from Finland, Norway, and Sweden.

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 70 - 72. Lancets of Pristiphora aphantoneura subgroup and P. frigida. 70 P. bifida PR. 408 VV 71 P. frigida NHRS-HEVA 000003873 72 P. pusilla PR. 369 VV.

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.