The genera of Nematinae (Hymenoptera, Tenthredinidae)

Abstract

Recent phylogenetic studies on Nematinae based on DNA sequences have shown extensive incongruencies with current nomenclature of genus-group taxa. Here, we expand previous DNA sequence datasets based on three genes (CoI, Cytb, and EF-1α), to include a fourth (NaK) and more genera. The analyses largely confirm the previous findings, particularly the existence of two well-supported large clades, Euura and Pristiphora, together comprising more than 75% of the species of Nematinae. Basal relationships within these two clades remain poorly resolved, mirroring the difficulties in delimiting genera based on morphology. In addition, a moderately supported small clade, Nematus, is found. The relationships between the Euura, Pristiphora, and Nematus clades are uncertain. Therefore, to stabilize the nomenclature we treat these clades as genera. This taxonomic treatment results in numerous new combinations of species names. The following synonymies are

North-Western Palaearctic species of Pristiphora (Hymenoptera, Tenthredinidae)

“…Some of the sequences analysed here were originally published by Nyman et al (2006Nyman et al ( , 2010, Prous et al (2014Prous et al ( , 2016, and Schmidt et al (2017).…”

“…1). There are no unambiguous morphological characters that define Pristiphora, but the combination of the following characters can be used to distinguish most of the species from the similar genera Nematus and Euura (see Prous et al 2014): clypeus usually more or less truncate (Fig. 9); apex of vein C usually swollen; head length behind eyes usually small; claws often with small subapical tooth or simple; in females, valvula 3 (apical sawsheath) often with scopa (e.g.…”

“…However, not all of these characters apply to all Pristiphora. For example, larvae of P. dasiphorae have only 3 visible annulets on abdominal segments and both species of the P. malaisei group (arctica group in Prous et al 2014), P. malaisei and P. dasiphorae, have setae also on annulet 1 (Zinovjev 1993). More Pristiphora species should be scored for the larval characters mentioned by Vikberg (1982) to test the reliability of these characters for defining the genus.…”

“…Pristiphora Latreille, 1810, as defined by Prous et al (2014), is the second largest genus in Nematinae (Tenthredinidae), including about 240 species (Taeger et al 2010). About half of these (120) are known in the West Palaearctic.…”

North-Western Palaearctic species of the Pristiphora ruficornis group (Hymenoptera, Tenthredinidae)

“…The third group (albitibia subgroup) includes three species feeding on Fabaceae (P. astragali, P. albitibia, and P. sootryeni), which have, uniquely within the ruficornis-group, on the inner surface of the lancet small spiny pectines (or dentes semicirculares) that reach the sclerora (Figs 41-45). The fourth group (armata subgroup) includes two species that feed on Crataegus (P. armata) and Tilia (P. leucopus), males of which have uniquely within Pristiphora, but similarly to Euura (as defined by Prous et al 2014), a distinct apical projection at the posterior end of tergum 8 (Fig. 16).…”