Plagionotus arcuatus (Linnaeus, 1758)

Królik, Roman, Kruszelnicki, Lech, Lasoń, Andrzej & Walczak, Marcin, 2021, Notes on the subspecies of Plagionotus arcuatus (Linnaeus, 1758) with description of a new subspecies from Iran (Coleoptera: Cerambycidae), Zootaxa 4942 (4), pp. 558-568 : 566

Key to subspecies of Plagionotus arcuatus (Linnaeus, 1758)

Because of the rather small number of voucher specimens available to us, we have constructed our key mainly based on the original descriptions, stating the dominant characters in each subspecies. There are specimens, however, which deviate in appearance from most members of their subspecies. For example: P. a. lugubris with red legs and antennae, and yellowish spots and stripes or else with uninterrupted elytral stripes; P. a. kirgizicus with exceptionally prominent median stripes on the pronotum and head (see Lazarev 2010); P. a. arcuatus with very dense pubescence on the sternites ( Figs. 1.A–B ). In our opinion, such deviant specimens confirm the close relationship between the various subspecies, and their sporadic occurrence in no way undermine the validity of dividing P. arcuatus into subspecies. These comments should be borne in mind when using the key given below.

1. Pronotum with well developed pale stripes on the anterior margin and in its middle part, head with distinct stripe of yellow pubescence behind the eyes ( Fig. 3C ).................................................................... 2.

- Pronotum and head usually without or with only very slightly developed pale stripes ( Fig. 3D )....................... 4.

2. Yellow stripes and spots on whole body well developed: first transverse elytral stripe (antemedian) large, “zigzag-like”, distance between first and second transverse stripe much smaller than width of first or second stripe ( Fig. 2G ); abdominal sternites almost covered by yellow, dense pubescence ( Fig. 2C–D ). Distribution range— Iran ( Fig. 5 )............................................................ P. arcuatus shirazensis Królik, Kruszelnicki, Lasoń & Walczak , new subspecies

- Yellow stripes and spots on body less developed: first transverse elytral stripe expanded horizontally, in presutural area not prolonged to spots behind scutellum, distance between first and second transverse stripe much greater than width of first or second stripe ( Fig. 2H ); yellow pubescence covering, at most, half of abdominal sternites........................... 3.

3. Antemedian transverse stripes on elytra extended horizontally, sometimes split into two spots, stripes behind middle of elytra regularly arching forwards ( Figs. 1.A–B ). Distribution range—Europe, North Africa & Asia Minor......................................................................................... P. arcuatus arcuatus (Linnaeus, 1758)

- Antemedian transverse stripes on elytra always divided into a strongly inclined outer stripe, well separated from the inner spot, stripes behind middle of elytra strongly arched forwards ( Figs. 1.C–D ). Distribution range— Crete ( Greece).......................................................................... P. arcuatus ghidottii Pesarini & Sabbadini, 2011

4. Transverse stripes of elytra usually well developed, complete ( Figs. 1.I–J ); antemedian stripes sometimes split into two spots. Distribution range— Kyrgyzstan............................................. P. arcuatus kirgizicus Lazarev, 2010

- Transverse stripes of elytra not so obvious, mostly reduced to small spots. Distribution range—Transcaucasia............ 5

5. Legs and antennae completely black, body pubescence usually white ( Figs. 1.G–H ). Distribution range— Armenia, Azerbaijan, Iran and Turkmenistan.................................................. P. arcuatus lugubris (Ménétriés, 1832)

- Legs and antennae partly red; body pubescence yellow ( Figs. 1.K–L ). Distribution range— Armenia, Azerbaijan and NE Turkey................................................................. P. arcuatus multiinterruptus Pic, 1933 .

Figures

FIGURE 1. A–L, habitus (dorsal view). Plagionotus arcuatus arcuatus: A, male, Poland (Lower Silesia), B, female, Greece (Thessaly reg.); Plagionotus arcuatus ghidottii: C, male, Greece (Crete, Chania reg.), D, female, Greece (Crete, Chania reg.); Plagionotus arcuatus lugubris: E, male, (Azerbaijan, Yardımlı reg.), F, female, (Iran, Mazandaran prov.), G, female, (Azerbai- jan, Yardımlı reg.), H, female, (Iran, Mazandaran prov.); Plagionotus arcuatus kirgizicus: I, male, (Kyrgyzstan, Jalal-Abad Prov.), J, female, (Kyrgyzstan, Jalal-Abad Prov.); Plagionotus arcuatus multiinterruptus: K, male, (Armenia, Gegharkunik Prov.), L, female, (Armenia Gegharkunik Prov.). Scale bar: 5 mm.

FIGURE 2. A–H, habitus. Plagionotus arcuatus shirazensis ssp. nov.: dorsal view, A, male (Iran, Fars Prov.), B, female (Iran, Fars Prov.), ventral view: C, male, (Iran, Fars Prov.), D, female, (Iran, Fars Prov.), E, holotype (Iran, Fars Prov.); Plagionotus arcuatus arcuatus: F, male (Turkey, Tunceli Prov.); Plagionotus arcuatus shirazensis ssp. nov.: G, male, (Iran, Fars Prov.). Plagionotus arcuatus arcuatus: H, female, Poland (Upper Silesia). Scale bar: 5mm.

FIGURE 3. A–B, Male genitalia of Plagionotus arcuatus shirazensis ssp. nov., A, tegmen, dorsal view, B, aedeagus, ventral view; C–D, differences in hair in two groups of subspecies, C, yellow pubescence behind the eyes in a Plagionotus arcuatus arcuatus, D, pale pubescence in a P. arcuatus lugubris. Scale bar: 1 mm (A–B) and 3 mm (C–D).

FIGURE 5. The places of origin of the analysed specimens the subspecies of Plagionotus arcuatus (Linnaeus, 1758): Plagionotus arcuatus shirazensis ssp. nov. (red circle), Plagionotus arcuatus arcuatus (green circle), Plagionotus arcuatus ghidottii (yellow circle), Plagionotus arcuatus lugubris (blue triangle), Plagionotus arcuatus kirgizicus (green triangle), Plagionotus arcuatus multiinterruptus (yellow triangle).