Phymatoceropsis Rohwer, 1916

Liston, Andrew, Mutanen, Marko, Heidemaa, Mikk, Blank, Stephan M., Kiljunen, Niina, Taeger, Andreas, Viitasaari, Matti, Vikberg, Veli, Wutke, Saskia & Prous, Marko, 2022, Taxonomy and nomenclature of some Fennoscandian Sawflies, with descriptions of two new species (Hymenoptera, Symphyta), Deutsche Entomologische Zeitschrift 69 (2), pp. 151-218 : 151

Phymatoceropsis Rohwer, 1916

Phymatoceropsis Rohwer, 1916: 107-109. Type species: Phymatoceropsis fulvocincta Rohwer, 1916, by original designation.

Dicrostema Benson, 1952: 97-98, 101. Type species: Selandria gracilicornis Zaddach, 1859, by original designation. Smith (1969): synonymy with Paracharactus. syn. nov.

Description.

Antennal flagellomeres proportionately narrow; flagellomere 1 3.2-4.7 × as long as distal width; the basal flagellomeres not widening distally, and setae normal (not long and coarse as in Phymatocera ). Outer orbit with pronounced groove behind nearly whole length of eye. Postgenal carina developed slightly below eye (clearly in P. sibiricola , but very weakly in P. gracilicornis ). Posterior of mesoscutellum with some conspicuous pits. Epicnemium variably developed, e.g. present in P. sibiricola , absent in P. gracilicornis . Claws with a small to minute inner tooth. Stub of 2A + 3A ( Astatus analis ) of fore wings straight, curved towards anterior, or furcate at apex; hind wing with enclosed cell M.

Diagnosis.

Phymatoceropsis can be distinguished from Rhadinoceraea by its proportionately narrower flagellomeres (flagellomere 1 3.2-4.7 × as long as distal width in Phymatoceropsis , 2.6-3.1 × as long as distal width in Rhadinoceraea ); basal flagellomeres not distally widened (widened in Rhadinoceraea ); outer orbit with pronounced groove behind whole length of eye (in Rhadinoceraea , if a groove is present, then this is behind only part of the eye. Phymatoceropsis differs from Lagonis in its mainly smooth mesepisternum (upper mesepisternum of Lagonis with numerous, large, crater-like pits). Phymatoceropsis can be separated from Paracharactus (based on North American species and the European P. hyalinus ) by the mesoscutellum having at least a row of deep, well-defined pits on the posterior part (mesoscutellum entirely without pits in Paracharactus ). Although in all examined specimens of Phymatoceropsis the stub of 2A + 3A of the fore wing is apically furcate (as is also usual in Rhadinoceraea ), and in most specimens of various Nearctic Paracharactus and the European P. hyalinus (Konow, 1886) ( Konow 1886a) the apex of 2A + 3A is straight, in some individuals of Nearctic Paracharactus species, as already noted by Smith (1969), it is furcate / curved strongly upwards, e.g. in P. rudis (Norton, 1861).

Comments.

The phylogeny of the Blennocampinae (Fig. 27 ) requires additional study, including analysis of genetic data obtained from a larger number of taxa. The large number of genus names currently in use as valid ( Taeger et al. 2010 listed over 100), and their often weak morphological characterization, lead us to suspect that significant “oversplitting” may have occurred. However, at present it seems reasonable to retain Phymatoceropsis as valid, and to place P. sibiricola and P. gracilicornis there. The synonymy of Phymatoceropsis and Dicrostema is based on the close genetic similarity of the type species of Dicrostema to Phymatoceropsis sibiricola , and because these two species possess the same combination of characters exhibited by other Phymatoceropsis species, including its type species. The host plant ranges of lineages of the Phymatocerini may correlate to a certain degree with their phylogeny. As far as is known, Rhadinoceraea species are attached to Iridaceae and Liliaceae ( Smith 1969), and Phymatoceropsis species to Adoxaceae , i.e. P. gracilicornis on Adoxa , and P. japonica and P. sibiricola on Sambucus . Interestingly, Sambucus species are also the hosts of Lagonis nevadensis , and L. opacicollis , which genetically also group with Phymatoceropsis , albeit with weak statistical support (Fig. 27 ). Unfortunately, the hosts of Paracharactus species are not known for certain. Smith (1969) reasoned that North American species might be attached to Carex , based on a tentative identification of a larva, whereas Lacourt (1985) speculated that the West Palaearctic P. hyalinus feeds on Ranunculus aconitifolius and R. platanifolius , without presenting any supporting data or observations. On the other hand, Okutani (1967) recorded the East Palaearctic Paracharactus leucopodus Rohwer, 1910 from Smilax ( Liliales , Smilacaceae ), but confirmation of this would be desirable. Both European Phymatoceropsis species are univoltine, as are probably nearly all Phymatocerini. Possible exceptions are Eurhadinoceraea ventralis ( Severin 1997) and Phymatocera aterrima ( Chevin and Silvestre de Sacy 2001), but the prolonged phenological periods of activity recorded for these species may be the result of polymodal emergence of adults, rather than true plurivoltinism.

Figures

Figure 27. Maximum likelihood tree of Blennocampinae and Allantinae based on mitochondrial COI and two nuclear genes (NaK and POL 2). Numbers at branches show SH-aLRT support (%) / ultrafast bootstrap support (%) values. Values of only well supported branches (> 90 for both) are shown. Letters " f " stand for " female ", " m " for " male ", and " l " for larva. Numbers at the end of the tip labels refer to sequence length.