Malayamiridius, Yasunaga & Chérot & Schwartz, 2021

Yasunaga, Tomohide, Chérot, Frédéric & Schwartz, Michael D., 2021, New genera and species of the Oriental mirine plant bugs from Southeast Asia, with six new combinations (Insecta: Heteroptera: Miridae: Mirinae: Mirini), Raffles Bulletin of Zoology 69, pp. 137-155 : 138-141

Malayamiridius , new genus

Type species. Malayamiridius nigrotenuis Yasunaga, Chérot & Schwartz , new species.

Diagnosis. Distinguished from superficially similar mirine genera (e.g., Adelphocoris Reuter , Creontiades Distant , Megacoelum Fieber , Orientomiris Yasunaga ) by the following combination of characters: Remarkably slender, parallel-sided body more than 3.5× as long as maximum width; moderate size (4.8−6.6 mm in total length); uniformly fuscous, shagreened, almost glabrous dorsum ( Fig. 1A ) with minute, reticular surface structure (cf. Fig. 2C, L ); smooth, roundly vertical head with a longitudinal mesal sulcation on vertex ( Fig. 2I, J ); a sharp spine at base of each claw ( Fig. 2 E−G); developed, lamellate parempodia ( Fig. 2E ); narrow pygophore with apical spine ventrally ( Fig. 2D ); generally short parameres ( Fig. 3A, B ); membranous endosoma with pair of narrow sclerotised supports on posterior surface and pair of small spiculate fields on membrane basad of secondary gonopore ( Fig. 3C, D ); broad, spade-shaped apex of gonapophysis I ( Fig. 9B ); and wide, broadly ovoid interramal lobe ( Figs. 3F , 8A ).

Description. Male. Body medium-sized, remarkably slender and elongate, parallel-sided, not sexually dimorphic in general shape. COLOURATION: Dorsum generally fuscous. SURFACE AND VESTITURE: Dorsum somewhat matte, weakly shining, covered with micro-reticulate structure, almost glabrous, pronotum, scutellum, hemelytron, and thoracic pleura with similar reticular structure ( Fig. 2L ); sparsely distributed, minute sensory setae, or trichobothria (which are invisible using light microscopy, cf. Fig. 2C ). STRUCTURE: Head: Somewhat bulbous, vertical in lateral view; eyes removed from anterior margin of pronotal collar; vertex with a shallow, longitudinal sulcus mesally; frons and clypeus flattened. Antenna: Longer than body, almost linear, not incrassate; segment I about as long as width of head across eyes, slightly longer than IV; segments II–IV almost uniform in thickness; segment III slightly shorter than II. Labium: Relatively short, reaching or slightly surpassing apex of mesocoxa, slightly shorter than antennal segment II. Thorax: Pronotum moderately rounded posteriorly; calli reduced, indistinct, with slightly raised posterior half; collar flattened, about as thick as base of antennal segment I; propleuron not margined nor carinate; metathoracic scent efferent system subtriangular, with narrow mesothoracic evaporatorium (or accessory evaporatorium, sensu Yasunaga & Duwal, 2019) ( Fig. 2B, K ); scutellum rather flat; mesoscutum without reticulation, only roughened. Hemelytron: Parallel-sided, weakly constricted at middle; cuneus small, about 1.5× as long as basal width. Legs: Long, generally slender; tibial spines short, sparse; meta-tarsomere I shorter than II or III; pretarsus with noticeable spine subbasally on each claw ( Fig. 2E–G ); parempodia lanceolate, lamellate, rather widened; pulvilli absent. Abdomen: Slender, parallel-sided, with apex reaching middle of forewing membrane (at level of apex of cuneus) in ventral view (as in Fig. 1B, C ). Genitalia ( Fig. 3A–D ): Pygophore short, slender, narrowly produced, somewhat flattened apically, with flat apical spine ventrally ( Fig. 2D ). Parameres generally short ( Fig. 3A, B ); left paramere C-shaped, with stout sensory lobe and L-shaped hypophysis terminated in a blunt, flattened tip. Phallotheca smooth; endosoma (vesica) membranous, supported on posterior surface by pair of long, narrow sclerites; anterior surface of membrane with pair of small spiculate or dentate fields basad of either side of secondary gonopore, membrane with larger basal field of spicules and with some apical spicules ( Fig. 3C, D ); ductus seminis weakly expanded apicad.

Female. As in male. Genitalia ( Figs. 3E, F , 8 A−C, 9A, B): Ovipositors generally stout ( Fig. 9A, B ); gonapophysis I with apical part significantly broadened, spade-shaped ( Fig. 9B ); gonapophysis II ( Figs. 8C , 9A ) with apical half expanded towards minutely teethed, sword-shaped apex. Lateral oviduct obscure. Sclerotised ring ( Fig. 3E ) crescent, rather thin-rimmed, with broadened posterolateral corner; dorsal labiate plate with spiculate posterior sclerite spanning bursa copulatix; ventral labiate plate broad laterally, narrow in middle, supporting spiculate intersegmental membrane continuous with dorsal structure of posterior wall. Posterior wall ( Figs. 3F , 8A, B ) with thick, broadly ovoid interramal lobe; dorsal structure reduced.

Etymology. Named for Malaya, combined with mirine genus Miridius Fieber (with similarly slender-bodied representatives); most of the specimens of the type species were collected in Malaysia and neighbouring areas; gender masculine.

Discussion. This unique genus is herein established for a single representative which has the following combination of distinct characters: Body fuscous, remarkably slender; dorsum shagreened, impunctate, nearly glabrous; ventral basal surface of each claw with noticeable spine; pygophore with flat ventral spine; endosoma [vesica] small-sized, almost entirely membranous, with a row of sharp spicules along gonoporal rim; female genitalia with apical region of gonapophysis I broadened, arrowed; dorsal labiate plate with spiculate sclerite on posterior margin spanning bursa copulatrix and interramal lobe of posterior wall wide, strongly developed, broadly ovoid.

Malayamiridius is most similar in general appearance to Creontiades Distant or Orientomiris Yasunaga , from which the present new genus can be distinguished by the abovementioned characters. Judging from the male and female genitalic structures, relationships between these three genera are considered to be only superficial (cf. Yasunaga, 1997; Yasunaga et al., 2001; Chérot & Malipatil, 2016).

The shagreened dorsal surface in Malayamiridius is formed by reticulated cuticle ultrastructure (cf. Fig. 2C, L ). Ficinus Distant, 1893 and Jornandes Distant, 1884 , two genera of New World Orthotylini ( Schaffner & Schwartz, 2008) have similar dorsal sculpturation, caused rather by minute punctation (see Schaffner & Schwartz, 2008: figs. 6A, 17A, 20A, 28A).

Figures

Fig. 1. Habitus images (A–C) of Malayamiridius nigrotenuis and environments on which the (UV lighting) sampling sites of the new mirines faced (D–E). A, M. nigrotenuis, holotype male from Perak, Malaysia; B, ditto, female in ventral view; C, ditto, male in ventral view; D, tropical rain forest of the type locality (Bukit Larut, Perak, Malaysia in January 1990); F, Brastagi, N. Sumatra, type locality of Sundacapsus flavonitidus (December 1989).

Fig. 2. Scanning electron micrographs for male (A–H) and female (I–M) of Malayamiridius nigrotenuis. A, left lateral habitus; B, ditto, anterior body; C, surface of corium; D, pygophore; E, pretarsal structure of proleg; F, protarsus; G, pretarsal structure of mesoleg; H, metatarsus; I, head and pronotum; J, head; K, scent efferent system; L, surface of pronotum, scutellum, and clavus; M, apical part of forewing.

Fig. 3. Male (A–D) and female (E–F) genitalia of Malayamiridius nigrotenuis. A, apex of pygophore in dorsal view; B, right paramere; C, D, endosoma; E, genital chamber, ventral view; F, posterior wall of bursae, anterior view. Scale bars = 0.1 mm.

Fig. 9. Female (A–D) and male (E–H) genitalia, and apical part of metaleg (I–J) of Malayamiridius nigrotenuis (A, B); Sundacapsus flavonitidus (C, D) and Tondomiris puguis (E–J). A, C, gonapophysis II; B, D, gonapophysis I; E, left paramere; F, right paramere; G, phallotheca; H, endosoma. Scale bars = 0.2 mm.

Fig. 8. Scanning electron micrographs of female and male (G–I) genitalia. A–C, Malayamiridius nigrotenuis; D–I, Sundacapsus flavonitidus; J, Lygocorides rubricans Yasunaga from Ryukyus, Japan; K, Orientomiris flavicollaris Yasunaga from Ryukyus; L, O. yaeyamanus Yasunaga from Ryukyus; M, Philostephanus rubripes (Jakovlev) from Nagasaki, Japan; N, O, P. ulmi (Kerzhner) from Russian Primorsky. A, D, E, J, M, N, posterior wall; B, K, L, interramal lobe; C, F, ovipositor (gonapophysis) I; G, apex of pygophore, caudal view; H, left paramere; I, right paramere; O, genital chamber.