Isometopus jejuensis Kim et Jung

Kim, Junggon & Jung, Sunghoon, 2016, Taxonomic review of the genus Isometopus (Hemiptera: Miridae: Isometopinae) from the Korean Peninsula, with description of a new species, Zootaxa 4137 (1), pp. 137-145 : 138-139

Isometopus jejuensis Kim et Jung sp. nov.

( Figs. 1 A, 1E, 4A, 6A)

Diagnosis. Recognized by the pale brown head, with distinct dark punctures; carina dark brown; antennal socket distinctly whitish pale brown; all dark antennae ( Fig. 1 A); face with dark punctures ( Fig. 1 E); pronotum dark brown with pale markings in middle and in each apex of posterior angle; apex of scutellum pale brown ( Fig. 1 A), apex of sclerotized ring of female genitalia sharply projected and slightly curved medially ( Fig. 4 A).

Description. Male: Unknown.

Female: Body oval, length 2.27–2.33. COLORATION: whitish pale brown and dark brown. Head: pale brown; ocellus reddish brown; carina dark brown; antennal socket distinctly whitish -brown; antennae dark brown except for pale apex of second antennal segment; face pale brown with a pair of dark markings and tiny dark punctures from the vertex to the genae; lorum dark brown; tylus dark brown; rostrum generally brown with the exception of pale margin and apex of dark brown first rostral segment. Thorax: pronotum mostly brown except for pale anterior part of pronotum and a pair of pale brown spots in humeral margin, with pale brown spot in middle; scutellum generally dark brown, with a pair of pale markings, apex of scutellum pale brown; hemelytra pale brown and dark brown; posterior part of corium with triangular dark marking, basal part of corium dark brown; clavus mostly pale brown, base and apex of clavus dark brown; embolium pale brown, apex and basal part of embolium dark brown; paracuneus dark brown; anterior part of cuneus pale brown, apical part of cuneus grayish and subhyaline; membrane grayish; legs generally dark brown; femur generally dark brown, 1/3 basal part and apex of femur pale brown; tibia generally dark brown, base and 1/3 apical part of tibia pale brown; tarsus brown. Abdomen: dark brown. SURFACE AND VESTITURE: pronotum, scutellum and hemelytra covered with densely golden pubescences, with distinct dark punctures. STRUCTURE: Head: flattened anteriorly with distinctly dark punctures, upper part width including compound eyes as wide as lower part width including lorum ( Fig. 1 E); ocelli present on vertex; vertex width narrower than compound eye width, vertex width approximately as wide as 1/2 length third antennal segment; antennae originated at ventral margin of head; antennae cylindrical in form; proportion of first to fourth antennal segments 0.1:0.5:0.3:0.2; rostrum reaching to ovipositor of abdomen; proportion of first to fourth rostral segments 0.2:0.3:0.3:0.4. Thorax: pronotum trapezoid, posterior margin of pronotum with two concave lines; mesoscutum broad; scutellum equilateral with two concave lines; lateral margin of hemelytra curved; cuneal fracture developed; membrane with one cell; legs generally slender; femur thick; tibia slender; tarsus with two segments. Abdomen: rounded, almost reaching to apex of membrane. GENITALIA: genital chamber somewhat simple, bursa copulatrix with distinct a pair of sclerotized rings; apex of sclerotized ring sharply projected and slightly curved medially ( Fig. 4 A).

Measurements. Female (n=5) Body length, tylus–apex of membrane: 2.27–2.33; head length, excluding collar: 0.24–0.26; head width, including compound eyes: 0.63–0.65; vertex width: 0.18–0.20; interocular width: 0.08–0.09; 1st antennal segment length: 0.09–0.10; 2nd antennal segment length: 0.49–0.51; 3rd antennal segment length: 0.35–0.26; 4th antennal segment length: 0.16–0.17; total antennal length: 1.09–1.14; 1st rostral segment length: 0.21–0.23; 2nd rostral segment length: 0.27–0.28; 3rd rostral segment length: 0.32–0.33; 4th rostral segment length: 0.36–0.38; total rostral length: 1.16–1.22; mesal pronotal length: 0.48–0.50; basal pronotal maximal width (straight): 1.18–1.22; anterior scutellum width: 0.85–0.90; mesal scutellum length: 0.81–0.86; outer embolial margin length (straight): 1.13–1.16; outer cuneal margin length (straight): 0.38–0.41; maximal width across hemelytron: 0.70–0.73; foreleg (femur: tibia: tarsus): 0.53–0.56:0.52–0.54:0.19–0.22; midleg (femur: tibia: tarsus): 0.55–0.57:0.64–0.67:0.22–0.27; hindleg (femur: tibia: tarsus): 0.61–0.68:0.82–0.85:0.26–0.29.

Materials examined. Holotype: [ CNU] 1♀, Jungmun-dong, Seogwipo-si, Jeju-do (Is.), Korea, 5.ix.2015, on Neolitsea sericea, J.G. Kim ; Paratypes: [ CNU] 11♀♀, same data as holotype.

Hosts. Neolitsea sericea (Blume) Koidz. (Lauraceae) *.

Etymology. Named after Jeju Island, type locality of this new species; a noun in apposition.

Distributions. Korea (Jeju Is.) *.

Discussion. This species is similar in general appearance to I. nigrosignatus in Taiwan and I. mirificus in Isigaki (Is.) in Japan, but it can be easily distinguished by dark brown pronotum and broad dark brown markings on hemelytra. This species is also similar to the northern species I. amurensis , which is distributed in Russia (Far East; Partizansk, Sukhanovka) and Korea (middle part), and found on oak trees ( Quercus mongolica and Quercus dentata ) and Taxus cuspidate ( Kerzhner, 1988; Jung et al., 2015). The new species is found on Neolitsea sericea (Lauraceae) as its host plant ( Fig. 6 A), which is only distributed in the southern region (Jeju Is.) of Korea ( Fig. 5 A). Additionally, it can be distinguished by dark brown second antennal segment and shape of sclerotized rings of female genitalia (See Jung et al., 2015).

Figures

FIGURE 1. Dorsal habitus and diagnostic characters of Isometopus spp. A, E: I. jejuensis sp. nov. Holotype, female; B – D, F – J: I. japonicus; B, D, F, H: male of I. japonicus; C, G, I: female of I. japonicus; A – C: dorsal habitus; D – G: head in anterior view; H – I: head in dorsal view; J: tarsus. Scale bar: A – C, 1 mm; D: 0.5 mm.

FIGURE 4. Sclerotized ring of female genitalia of Isometopus spp. A: I. jejuensis sp. nov.; B: I. japonicus; C: I. amurensis. Scale bar: 0.1 mm.

FIGURE 5. Host plants of Isometopus spp. A: Neolitsea sericea (Lauraceae), host plant of I. jejuensis sp. nov.; B: Zelkova serrata (Ulmaceae), host plant of I. japonicus.

FIGURE 6. Live adult and nymphs of Isometopus spp. A: Adult of I. jejuensis sp. nov. B: adult of I. japonicus; C: young nymphs (2 nd instar and 3 rd instar) of I. japonicus around mosses; D: last instar of I. japonicus.