Pristiphora bifida (Hellen, 1948)

Nematus (Pristiphora) bifidus Hellén, 1948: 116-117. Lectotype ♀ (http://id.luomus.fi/GL.5214; here designated) in MZH, examined. Type locality: Malla, Kilpisjärvi, Enontekiö, Finland.

Similar species.

Externally, perhaps the most similar species is P. frigida, from which it can be distinguished by having pale hind trochanters, trochantelli, and tibiae (black or brown in P. frigida). In addition, antennae of males have numerous and clearly visible stout black setae among finer paler ones (Fig. 36), while in P. frigida there are only a few barely visible ones (Fig. 35). The lancets (Figs 70-71) and penis valves (87-88) are also different. Apical serrulae are somewhat shorter and more protruding and the tangium of the lancet tends to be longer and narrower (Fig. 70) than in P. frigida (Fig. 71). The penis valve lacks (Fig. 87) a membranous fold near the tip of the ventro-apical spine (present in P. frigida; Fig. 88) and the pseudoceps has a distinct dorsal depression in the middle or basal part (absent in P. frigida).

Genetic data.

Based on COI barcode sequences, P. bifida belongs to the same BIN cluster (BOLD:AAG3568) as P. aphantoneura, P. confusa, 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. Only one partial TPI sequence (sequencing of the first exon and part of the following intron failed apparently because of intron length polymorphism) of P. bifida is available, which can be distinguished from other species (Fig. 2).

Host plants.

Salix viminalis L. (Liston and Burger 2009). In Kilpisjärvi (Finland) some other species must be the host, as S. viminalis does not occur there.

Distribution and material examined.

Western Palaearctic. Specimens studied are from Finland, Germany, Norway, and Sweden. According to the BOLD database, this species may also be present in North America. The identifications of North American specimens falling within BIN cluster BOLD:AAG3568 are however uncertain.