A new chestnut-feeding species of Stomaphis Walker (Hemiptera: Aphididae Lachninae) from Korea Author Lee, Minho Insect Biosystematics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea. Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul 08826, Korea. Author Kanturski, Mariusz Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Bankowa 9, 40 - 007 Katowice, Poland. Author Lee, Seunghwan Insect Biosystematics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea. Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul 08826, Korea. text Zootaxa 2022 2022-09-12 5183 1 273 281 journal article 140864 10.11646/zootaxa.5183.1.21 860f2ed6-6c33-4855-b32b-6e7db10e45bc 1175-5326 7070210 8E979AEE-DD0F-4E0E-8D46-5CEAF29AB2D2 Stomaphis ( Stomaphis ) blackmani Lee, Kanturski & Lee , sp. nov. ( Figs 1A, 1C, 1D, 1F, 1H , 2 , and 3; Table 1 ) Type material. Holotype : apterous viviparous female ( Fig. 2 ), South Korea , Seoul , Gwanak-gu , Gwanak-ro 1, Mt. Gwanak , on C . crenata , 16.ix.2020 , leg. M. Lee , [200916-LMH-1-1], (SNU). Paratypes : (collected from the same tree and colony as the holotype ) 3 apterous viviparous females, ditto as holotype , 19.vi.2020 , leg. M. Lee, [200619-LMH-1-1, 2, 3] (SNU), 1 alate viviparous female, ditto as holotype , 19.vi.2020 , leg. M. Lee, [200619-LMH-1-4] (SNU), 1 apterous viviparous female, ditto as holotype , 10.vii.2020 , leg. M. Lee, [200710-LMH-3-1] (SNU), 2 apterous viviparous females, ditto as holotype , 14.viii.2020 , leg. M. Lee, [200814-LMH-1-1, 2] (SNU), 1 apterous viviparous female, ditto as holotype , 16.ix.2020 , leg. M. Lee, [200916- LMH-1-2] (SNU). The holotype and paratypes are deposited in the College for Agriculture and Life Sciences, Seoul National University Seoul , Korea (SNU). One paratype is also deposited in National Institute of Biological Resources (NIBR). Diagnosis There are three eastern Palaearctic species (including the new one here described) currently placed in Stomaphis having ventral side of the abdomen with 5 long barrel-shaped sclerotized ventral plates, AbdT I–VII with a pair of large spinal sclerites, URS longer than HT II, and HT II as long as Ant VI: S . carpini Sorin, 1965 , S . yanonis Takahashi, 1918 ( Binazzi and Blackman 2003 ; Inouye 1938 ; Qiao and Zhang 1999 ; Sorin 1965 ; Sorin 1979 ; Sorin 1995 ; Sorin 2012 ; Szelegiewicz 1975 ; Takahashi 1925 ; Takahashi 1960 ; Zhang and Zhong 1982 ; Zhang and Zhong 1985 ). Among them, the new species is most similar to S. yanonis . The ratio of hind tibiae to hind femora is more than 1.40 ( 1.47–1.59 in the new species and about 1.50–1.60 in S . yanonis ), while in S . carpini (about 1.34) it is less than 1.40 ( Sorin 1965 ). The apterous viviparous female of S . blackmani is also distinguished from S. yanonis by the following points ( Figs 2 and 4 ; Table 1 ): 1. URS 0.64–0.68 mm , 0.52–0.58 mm in S . yanonis ; 2. Ant IV 0.24–0.33 mm , 0.35–0.42 mm in S . yanonis ; 3. The ratio of PT to Ant VIb is less than 0.20 (0.12–0.19, average: 0.16), more than 0.20 (0.21–0.28, average: 0.23) in S . yanonis ; 4. The ratio of Ant V to III is less than 0.53 (0.49–0.52, average: 0.51), more than 0.53 (0.55–0.59, average: 0.56) in S . yanonis ; 5. The ratio of Ant IV to III is less than 0.48 (0.32– 0.46, average: 0.40), more than 0.48 (0.50–0.56, average: 0.52) in S . yanonis ; 6. The ratio of URS to Ant III is more than 0.82 (0.86–0.97, average: 0.91), less than 0.82 (0.70–0.81, average: 0.77) in S. yanonis . Description. Apterous viviparous female (based on eight type specimens), ( Figs 1F and 2 ; Table 1 ) FIGURE 1. Comparison of Stomaphis blackmani sp. nov. and S . yanonis : S . blackmani sp. nov. on the surface of the Castanea crenata : (A) ant chambers; (C) ant chambers under the bark; (D) in bark crevices (not inside ant chambers; same tree); (F) apterous viviparous female, (H) alate viviparous female, S . yanonis on the surface of the Celtis sinensis (B) ant chambers; (E) ant chambers under the bark; (G) apterous viviparous female; (I) alate viviparous female. TABLE 1. The biometric measurement of the apterous and alate viviparous females of S . blackmani sp. nov. and S . yanonis

Species	S . blackmani sp. nov.		S . yanonis
Character	apterous viviparous female (n=8)	alate viviparous female (n=1)	apterous viviparous female (n=8)	alate viviparous female (n=3)
BL	4.92 (4.68–5.46)	3.94	5.08 (4.80–5.28)	4.31 (3.98–4.68)
Maximum width	2.47 (2.07–3.07)	1.55	2.72 (2.42–3.01)	1.84 (1.75–1.89)
HW	1.32 (1.27–1.39)	1.13	1.30 (1.20–1.39)	1.13 (1.11–1.15)
Antennae length	2.21 (2.13–2.32)	2.14 (2.10–2.18)	2.69 (2.51–2.86)	2.16 (2.07–2.29)
Ant III	0.71 (0.68–0.77)	0.70 (0.69–0.72)	0.73 (0.70–0.78)	0.74 (0.70–0.79)
Ant IV	0.28 (0.24–0.33)	0.33 (0.32–0.33)	0.38 (0.35–0.42)	0.32 (0.31–0.34)
Ant V	0.37 (0.34–0.39)	0.36 (0.35–0.36)	0.41 (0.39–0.45)	0.35 (0.34–0.36)
Ant VIb	0.38 (0.36–0.41)	0.33 (0.32–0.34)	0.37 (0.32–0.40)	0.33 (0.31–0.34)
PT	0.06 (0.05–0.08)	0.06 (0.06–0.07)	0.08 (0.08–0.10)	0.06 (0.06–0.07)
Hind femora length	1.34 (1.24–1.47)	1.28 (1.27–1.29)	1.44 (1.34–1.54)	1.48 (1.45–1.52)
Hind tibiae length	2.04 (1.91–2.24)	2.13 (2.12–2.14)	2.31 (2.05–2.50)	2.29 (2.25–2.33)
MT II	0.27 (0.25–0.30)	0.26 (0.25–0.27)	0.29 (0.27–0.32)	0.28 (0.28–0.29)
HT I	0.12 (0.12–0.14)	0.13 (0.12–0.14)	0.13 (0.13–0.15)	0.12 (0.11–0.13)
HT II	0.43 (0.40–0.49)	0.39 (0.39–0.39)	0.47 (0.45–0.51)	0.38 (0.37–0.39)
URS	0.66 (0.64–0.68)	0.63	0.57 (0.52–0.58)	0.50 (0.50–0.51)
SIPH sclerite length	0.55 (0.48–0.67)	0.44 (0.44–0.45)	0.67 (0.64–0.73)	0.58 (0.56–0.61)
SIPH sclerite width	0.31 (0.26–0.41)	0.27	0.43 (0.38–0.47)	0.30 (0.30–0.30)
GP length	0.34 (0.29–0.39)	0.23	0.32 (0.28–0.35)	0.25 (0.23–0.26)
GP width	0.71 (0.63–0.77)	0.47	0.77 (0.68–0.86)	0.55 (0.52–0.58)
Forewing length	–	3.86 (3.83–3.89)	–	4.14 (3.79–4.39)
Forewing width	–	1.18 (1.15–1.20)	–	1.25 (1.06–1.36)
RH Ant III	2.60 (0–13)	18 (16–20)	0	12.66 (10–15)
RH Ant IV	5 (4–7)	5 (5–5)	4.44 (1–6)	5.16 (5–6)

Colour (alive specimens) ( Fig. 1F ). Body shining dark green and brown, slightly covered by white wax. Head and pronotum dark brown. Antenna brown with bases of Ant III light brown. Legs light brown, femora and tibiae brown with darker knee area, hind tarsi dark brown. URS, SIPH sclerites, GP, cauda, and ventral plates dark brown. (Pigmentation of mounted specimen) ( Fig. 2 ): Body brownish, head and pronotum dark brown. Antenna brown with bases of Ant III light brown. Legs brown, femora and tibiae brown with darker knee area, hind tarsi brown. URS, SIPH sclerites, GP, cauda, and ventral plates dark brown. Morphometric characters : Body large elliptical, covered with short pubescence. Head short, wide, sclerotized, compound eyes with a triommatidium. Antennae ( Fig. 2G ) about 0.42–0.48 times body length. Ant VI longer than Ant V. Antennal ratios: PT/Ant VIb 0.12–0.19, V/III 0.49–0.52, IV/III 0.32–0.46. Rostrum, about twice as long as body ( Fig. 2A ). URS 0.86–0.97 times Ant III and 1.44–1.62 × HT II. HT II 1.53–1.66 times MT II. Labrum covered with 41–55 hairs. Head and pronotum sclerotized, mesonotum with a pair of spinal sclerites and a pair of large marginal sclerites, metanotum with a pair of spinal sclerites and a pair of small marginal sclerites. AbdT I, II with a pair of small marginal clusters of sclerites. AbdT I–VII with a pair of large spinal sclerites. AbdT VIII with a sclerotic band, divided in the middle. Ventral side of the abdomen with 5 long barrel-shaped sclerotized ventral plates. Abdominal segment VIII with latero-ventral processi. SIPH pore surrounded by a sclerified plate. GP oval in shape and cauda rounded. Other measurements and morphological differences are given in Table 1 . FIGURE 2. S . blackmani sp. nov. , apterous viviparous female (holotype): (A) body, (B) SIPH, (C) GP, (D) HT II, (E) URS, (F) hind tibia, (G) whole antennal segments. Scale lines for (A)=1 mm, B–E=0.1 mm, F–G=0.5 mm Alate viviparous female. (based on one specimen ), ( Figs 1H and 3 ; Table 1 ) Colour (alive specimen) ( Fig. 1H ): Body dark green and brown. Head and Pronotum sclerotized. Thorax shining dark brown. Antenna brown with bases of Ant III light brown. Legs brown, femora and tibiae brown with darker knee area, hind tarsi brown. SIPH sclerites, GP, cauda, and ventral plates dark brown. Middle of URS pale. (Pigmentation of mounted specimens) ( Fig. 3 ): Body brownish, head and pronotum dark brown. Antenna brown with bases of Ant III light brown. Legs brown, femora and tibiae brown with darker knee area, hind tarsi brown. URS, SIPH sclerites, GP, cauda, and ventral plates dark brown. Middle of URS pale ( Fig. 3C ). Morphometric characters : Body large cylindrical, covered with short pubescence. Head short and sclerotized. Compound eyes with a triommatidium. Antennae ( Fig. 3E ) about 0.53–0.55 times body length. Antennal ratios: PT/Ant VIb 0.18– 0.20, V/III 0.48–0.52, IV/III 0.45–0.46. Ant III and IV with unequal circular secondary rhinaria. Rostrum very long, about twice as long as the body. URS 0.87–0.91 times ANT III and 1.61–1.65 × HT II. HT II 1.40–1.56 times MT II. Labrum covered with 39 hairs. Forewing with pterostigma dark, M vein centered between the radial sector and cubitus 1, with one fork ( Fig. 3A ). Forewing length 0.97–0.98 times body length. Head, pronotum, and mesonotum sclerotized, metanotum with a pair of spinal sclerites and small marginal sclerites. AbdT VII with a pair of sclerotic bars. Ventral side of the abdomen with 5 long barrel-shaped sclerotized ventral plates. SIPH pore surrounded by sclerited plate. GP oval in shape. Cauda rounded. Other measurements and morphological differences are given in Table 1 . Etymology. The species name is given in honor of the late Dr. Roger Blackman, who worked on the world aphid fauna. Distribution. Currently, it is only recorded from Mt. Gwanak, Seoul , South Korea . Host plant. Castanea crenata Siebold & Zucc. (Fagaceae) . FIGURE 3. S . blackmani sp. nov. , alate viviparous female: (A) body, (B) HT II, (C) URS, (D) hind tibia, (E) whole antennal segments. Scale lines for (A)=1 mm, B–C=0.1 mm, D–E=0.5 mm Biology. This Stomaphis species feeds on the basal part of the chestnut tree, at ground level or up to about 1.3 m above the ground ( Figs 1A, 1C, and 1D ). Occasionally some individuals live in chambers made of soil by ants ( Figs 1A and 1C ), but mainly observed in crevices outside the chamber ( Fig. 1C ). It is attended by ants ( Lasius sp. ) while from 14 August to 16 September the presence of Pristomyrmex punctatus (Smith, 1860) (Myrmicinae) was observed.