Rubrocuneocoris Schuh, 1984

Duwal, Ram Keshari, Schwartz, Michael D. & Yasunaga, Tomohide, 2019, A new species of the plant bug genus Rubrocuneocoris (Hemiptera: Heteroptera: Miridae: Phylinae) from Vietnam, Zootaxa 4652 (1), pp. 165-173 : 166-168

Rubrocuneocoris Schuh

Rubrocuneocoris Schuh 1984: 424 (n. gen.). Type species by original designation: Rubrocuneocoris acuminatus Schuh 1984 ; Yasunaga 2001a: 117 (diag.); 2001b: 179 (diag.); Schuh 2002 -2014 (cat. on web).

Diagnosis. The species of this genus are recognized by small body size; variously colored body and dorsum (pale, or yellow, or orange, or pale and black); simple vestiture, usually with pale setae on dorsal and ventral surfaces; presence of distinct red spots or markings on apices of embolium and cuneus; long labium surpassing metacoxa and reaching abdominal segments, except R. albescens with a short labium reaching the apex of the metacoxa; enlarged metafemora, large pulvillus; and semi-coiled or coiled endosoma with an attenuated apex and sub-apically located secondary gonopore (see detailed description in Schuh 1984, pg. 424).

Distribution. Pacific Islands, Oriental and Palearctic regions.

Discussion. The host association of most Rubrocueocoris species are unknown as many were collected at light. According to references, the genus occurs on wide range of host plants, such as R. nigriceps taken on the flowering tree, Castanopsis indica (Roxb.) Miq. (Fagaceae) ( Duwal et al. 2010), and R. calvertae , collected on Macaranga tanarius (L.) Müll. Arg. ( Euphorbiaceae ) and Pipturus sp. ( Urticaceae ) ( Henry 2017), R. albescens on Pterostyrax corymbosus Siebold & Zucc (Styracaceae) , and R. quercicola on Quercus dentata Thunb. (Fagaceae) (Kerzhner 1988).

Rubrocuneocoris is one of the six genera placed in the tribe Decomiini ( Schuh & Menard 2013) and is now known to contain ten species, including a new species described herein. The members of the genus are variably colored with the dorsum pale white or yellow, or with dark patterns (black or fuscous) or orange; usually with distinct red spots or markings on apices of the embolium and cuneus. In general, Rubrocuneocoris can be confused with Decomia Poppius (1915) due to similar dark markings but the latter genus is easily recognized by the semi-hyaline or hyaline hemelytra.

Species of Rubrocuneocoris are found with two types of endosoma. The one we describe here from Vietnam is close to the Chinese species with having simple, stout endosoma, which is different from others. Therefore, we conclude species of Rubrocuneocoris probably arose from two lineages. However, further investigations of more taxa and genomic data are necessary to help clarify their taxonomic status.

We note that a species of Rubrocuneocoris described from China, R. lanceus Li & Liu 2008 , was transferred to the genus Atractotomoidea Yasunaga 1999 by Yasunaga & Duwal (2015) because it possesses similar morphological and genitalic structure as the type species A. castanea Yasunaga, 1999 . However, four species of Rubrocuneocoris described from Taiwan by Lin (2006): R. falcis , R. maculosus , R. nodus , and R. trifidus , were not treated by Yasunaga & Duwal (2015). Also, Henry (2017) mentioned in his diagnostic note that the species described from Taiwan have black, gray, or red spots on the dorsum which is unlike the dorsum of most species included in Rubrocuneocoris . Consequently, we have concluded, based on the dorsal habitus photographs and illustrations of the male genitalia, that the four Taiwanese species are not congeneric with species of Rubrocuneocoris .

The recent revised classification by Schuh & Menard (2013) place Atractotomoidea and Rubrocuneocoris in different tribes, Nasocorini and Decomiini respectively. The hind femora in members of the Nasocorini bear a row of distinct spicules on the dorsal distal margin and the dorsal setae and other body vestiture are variable, with either erect or sub-erect pale or black simple setae and with or without scale like setae. Most species of Atractotomoidea have uniformly distributed minute dark spots on the dorsum, simple pale sub-erect setae covering the dorsum and the labium usually only reaches the apices of the metacoxa. As in other genera of Nesocorini, the species of Atractotomoidea bear a row of spicules on dorsal distal margin of the hind femora (we confirmed this feature on two specimens of Atractotomoidea present in our collection). The endosoma is mesially coiled or semi-coiled, with 2 to 3 apical straps, the secondary gonopore is removed from the apex of the endosoma, and the female genitalia have a asymmetrical anterior wall as in Duwal et al. (2010, pg. 41, cf. Fig. 18) in Atractotomoidea monticola Duwal et al., 2010 and A. orientalis Duwal et al. 2010 .

In contrast, members of tribe Decomiini have a single type of appressed simple pale setae as mentioned in Schuh & Menard (2013). The species of Rubrocuneocoris do not have spots on the dorsum except for distinct red spots or markings on the apices of embolium and cuneus and labium usually reaches the abdominal segments, except in R. albescens , which has a short labium reaching metacoxa. The endosoma is coiled or semi-coiled and variously structured apically, with the secondary gonopore mesial or sub-apical. In the female genitalia, the anterior wall is symmetrical and has a unique circular sclerite on the dorsal labiate plate as presented in Duwal et al. (2010, pg. 42, cf. Fig. 19) and Fig 4 E–F.

Although, Lin (2006) did not mentioned a row of spicules on dorsal distal margin of the metafemur, other characters described above, together with male genital structures, suggest that four species of Rubrocuneocoris documented from Taiwan undoubtedly represent the members of Atractotomoidea . Therefore, we propose the following new combinations: Atractotomoidea falcis ( Lin 2006) n. comb.; A. maculosus ( Lin 2006) n. comb.; A. nodus ( Lin 2006) n. comb.; and A. trifidus ( Lin 2006) n. comb.

Figures

FIGURE 4. Genitalic structures of Rubrocuneocoris albescens. A–D, Male. E–I, Female. A—Phallotheca. B—Left paramere. C—Right paramere. D—Endosoma. E—Bursa copulatrix, dorsal view. F—Bursa coppulatrix, ventral view. G—Posterior wall. H. Gonapophysis I. I—Gonapophysis II. Abbreviation: Male: ds: dorsal strap, sg: secondary gonopore, vs: ventral strap; Female: dlp: dorsal labiate plate, pm: posterior membrane, sclr: sclerotized ring, smrcpt: seminal receptacle.