Decomia ishikawai Yasunaga, Duwal & Lee

Yasunaga, Tomohide, Duwal, Ram Keshari, Oh, Minsuk & Lee, Seunghwan, 2016, A new species of Decomia Poppius from Laos and Thailand, with an annotated checklist and keys to genera and species of tribe Decomiini from Indochina (Hemiptera: Heteroptera: Miridae: Phylinae), Zootaxa 4189 (2), pp. 301-310 : 305-310

Decomia ishikawai Yasunaga, Duwal & Lee , n. sp.

( Figs. 3 , 4 A −C; 5)

Diagnosis. Recognized by its largest size among Asian congeners; generally fuscous basic coloration ( Fig. 3 ); reddish castaneous abdomen, elongate, broad, C-shaped endosoma ( Fig. 4 C); and elongate female bursa copulatrix ( Fig. 5 ). Most similar in general appearance to D. cephalotes Poppius (known from Ryukyus, Japan and Taiwan), D. nigrissima Yasunaga ( Thailand) and D. torrevillasi Schuh ( Philippines) ; distinguished from them readily by its even larger size (e.g., total length more than 2.9, length apex of clypeus to cuneal fracture 1.96, head width across eyes more than 0.83 and basal width of pronotum 1.25), generally castaneous abdomen, and elongate, C-shaped endosoma moderately widened apically ( Fig. 4 C).

Description. Body generally fuscous, ovoid, large; dorsal surface shining, with uniformly distributed, simple, silky, reclining setae. Head wholly shiny black, rounded; apical 1/3–2/3 of clypeus tinged with red. Antenna yellowish brown; segment II black, with yellowish brown basal half, somewhat clavate; apices of III and IV brown. Labium shiny dark reddish brown, reaching apex of metacoxa. Pronotum shiny black, with rather sparse vestiture; pleura partly shagreened; scent efferent system dark brown; scutellum black, flat, with densely distributed, silvery, reclining setae along anterior margin. Hemelytron hyaline, weakly tinged with brown; apex of clavus dark brown; apex of embolium narrowly darkened; apical 1/4 of cuneus infuscate; membrane pale brown, nearly transparent, with slightly brownish veins. All coxae and femora shiny black; each trochanter reddish or yellowish brown; apices of pro- and mesofemora yellow; metafemur about 2.5 times as long as its maximum thickness; all tibiae and tarsi yellowish brown; apices of metafemur and each tibia slightly tinged with red; meta-tarsomere I about as long as II; segment III slightly shorter than I or II; pretarsus with broad, crescent pulvilli. Abdomen reddish castaneous, with posterior margin of each segment dark brown. Male genitalia as in Fig. 4 A −C. Generally large in size (c.f., Fig. 4 I, J for D. nigrissima ); apical part of phallotheca curved and tapered ( Fig. 4 A); left paramere weakly sprayed-out ( Fig. 4 B); endosoma elongate, C-shaped, with moderately widened apical part; secondary gonopore developed ( Fig. 4 C). Female genitalia ( Fig. 5 ): Bursa copulatrix generally elongate, with laterally folded dorsal labiate plate; sclerotized ring ovoid, thick-rimmed, somewhat narrowed at anterior corner; posterior wall elongate, more extensively projected comparing with that possessed by other congeners.

Measurements (male/female): Total body length 2.92/ 3.00; length from apex of clypeus to cuneal fracture 1.96/ 1.96; width of head across eyes 0.83/ 0.86; vertex width 0.38/0.45; lengths of antennal segments I −IV 0.20, 0.51, 0.25, 0.26/ 0.20, 0.52, 0.28, 0.31; labial length 1.26/ 1.52; basal width of pronotum 1.25/ 1.34; maximum width across hemelytron 1.38/ 1.47; and lengths of metafemur, tibia and tarsus 1.05, 1.35, 0.50/ 1.10, 1.37, 0.49.

Etymology. Named after Dr. Tadashi Ishikawa, who first collected this new species.

Type material. Holotype male: Thailand: Chiang Mai, Doi Suthep, Chiang Khian 850 m alt., 16 Aug 2001, T . Ishikawa ( DOAT) ( AMNH _PBI 00380465) . Paratypes: Laos: Xiang Khoang, Kham District, Phosabous Nature Protection Area , Namchack Village , 2 May 2015, Oh , 1 male ( SNU, Coll# 150429 -MS-21) (00380470) . Thailand: same data as for the holotype, 2 females ( TYCN) (00380471, 00380472).

Discussion. This unique new species is easily recognized by the fuscous, large body (cf. Fig. 3 ). Based on the blackish basic coloration (and the hemelytron without any rouge or orange-red macula), it at first sight appears to belong to a group of species including D. cephalotes Poppius (known form Ryukyus, Japan and Taiwan), D. gressitti Schuh ( Papua New Guinea), D. maai Schuh (Irian Jaya, Indonesia), D. nigrissima Yasunaga ( Thailand) , and D. torrevillasi Schuh ( Philippines) . Judging from the shape of endosoma, these blackish members are evidently divided into two groups, ‘ cephalotes + torrevillasi ’ (with medium-sized, apically developed endosoma and thickrimmed secondary gonopore) and ‘ gressitti + maai + nigrissima’ (with tiny, slender, J-shaped endosoma and reduced secondary gonopore, as in Fig. 4 E). However, D. ishikawai belongs to neither of them; its remarkably large, C-shaped endosoma is most similar to that possessed by D. srilankensis Schuh which is, in spite of its light and partly reddish color pattern, also anticipated to have the elongate female bursa copulatrix ( Fig. 5 ). It is our opinion that the similarity of general coloration in Decomia species may represent a convergence.

Figures

FIGURE 3. Habitus images of Decomia ishikawai n. sp., comparing with two most common Indochinese congeners, D. chiangdaoensis and D. indochinensis, dry-preserved specimens.

FIGURE 4. Male genitalia of Decomia spp. (A – J) and Rubrocuneocoris nigriceps (K – M). A & K. Apex of pygophore with phallotheca in dorsal view. B, D & L. Left paramere. C, E – J, M. Endosoma. Scale bars 0.2 mm (except for D – F = 0.1 mm).

FIGURE 5. Female genitalia of all currently known Indochinese Decomia spp. and Decomioides kazutakai.