Two new deraeocorine plant bug species from Japan (Heteroptera, Miridae, Deraeocorinae)

Abstract Two new deraeocorine plant bug species, Fingulushenrytomi and Stethoconustakaii, are described from Japan. A color habitus image of live individuals and scanning electron micrographs are shown for each taxon to aid an unequivocal identification. A checklist and keys to species are also provided for Japanese Fingulus and Stethoconus.


Introduction
The plant bug subfamily Deraeocorinae is the fifth largest in the family Miridae (Henry 2017). This group is defined by a toothed tarsal claw, hair-like parempodium (Figs 22,(27)(28) and membranous endosoma, sometimes with sclerites on the lobes. The subfamily contains numerous predatory species that sometimes resemble their insect prey. Previous studies of the Japanese fauna of this subfamily include those by Miyamoto (1965) and Nakatani (1995Nakatani ( , 1996, which have resulted in thirtynine species being confirmed. The present paper documents two new species of the Deraeocorinae, Fingulus henrytomi (tribe Deraeocorini) and Stethoconus takaii (Hyaliodini), which were found in the temperate climate zones of southeastern Japan. Although the majority of the members of Fingulus Distant and Stethoconus Flor are thermophilic and known predominantly from the tropics and subtropics (Nakatani et al. 2000, Nakatani and Yasunaga 2001, Schuh 1995, 2002-2014, Stonedahl and Cassis 1991, Yasunaga et al. 1997, 2016, the new species extend the range of these genera farther north than expected. The new species are also considered predacious, as species belonging to Fingulus and Stethoconus in other regions are well known as predators (e.g., Henry et al. 1986;Neal et al. 1991;Wheeler 2001;Yasunaga et al. 1997Yasunaga et al. , 2016. Color habitus images of live individuals and scanning electron micrographs are presented for the two new species and their closely related congeners.

Materials and methods
Specimens used in this present work were deposited in American Museum of Natural History, New York, USA (AMNH); Institute of Agro-Environmental Sciences, NARO (NIAES) and T. Yasunaga Collection (TYCN). Terminal segments of the male abdomen were boiled in 5% KOH solution for 5 min to observe the genital structures. Matrix code labels are attached to the holotype and some representative specimens, which uniquely identify each specimen, and are referred to as 'unique specimen identifiers' (USIs). The USI codes [e.g., AMNH_PBI 012345] comprise an institution and project code (AMNH_PBI) and a unique number (012345). These data were digitized on the Arthropod Easy Capture (formerly the Planetary Biodiversity Inventory) database maintained by the American Museum of Natural History, New York, USA (http:// research.amnh.org/pbi/) and are also searchable on 'Heteroptera Species Pages' (http:// research.amnh.org/pbi/heteropteraspeciespage/). All measurements were made with an ocular micrometer and are given in millimeters. The synonymic lists for known taxa were omitted, as comprehensive catalogs are now available (Schuh 1995(Schuh , 2002(Schuh -2014Kerzhner and Josifov 1999;Aukema et al. 2013 online catalog). Scanning electron micrographs were taken with a Hitachi Tabletop Microscope TM3030.

Genus Stethoconus Flor, 1861
S. japonicus, Schumacher, 1917: Japan (Honshu, Shikoku, Kyushu, Ryukyus)  Diagnosis. Dorsum dark brown with a pair of pale markings on hemelytra; head slightly pale; pronotum trapeziform, strongly convex; femora and bases of tibiae infuscate. In general appearance, this new species resembles F. collaris Miyamoto, from which it can be distinguished by its hemelytral coloration.
Measurements Distribution. Japan (Shikoku: Kochi Pref., Tsushima Island). Biology. The habits of this new species remain unknown; the only information is that the type specimens were collected by using a UV light trap or sweeping broadleaf trees.
Remarks. This new species can be distinguished from its congeners by the coloration described above. Based on the generally ovoid body and rather weakly porrect head, our new species is assumed to be most closely related to F. collaris. As in certain other congeners, the population density of F. henrytomi is extremely low, as only two females have been collected, in spite of our continuing efforts and those of our enthusiastic colleagues to find additional specimens.
Description. Body generally maculate; dorsum shiny, densely clothed with long erect yellowish setae. Head shiny yellowish brown; brown stripe on vertex. Antenna dark brown; basal 1/3 or half of segment I somewhat pale, sometimes tinged with red; middle portion of segment II sometimes pale; base of segment III pale. Labium yellowish brown except tip brown, reaching anterior margin of mesosternum. Pronotum dark brown with yellowish quotation mark-shaped markings, strongly convex and distinctly punctate, densely covered with long erect yellowish setae; collar yellowish brown with dark base punctate, length 0.56 of width; triangular yellowish marking on mesal calli; short longitudinal whitish stripe on base of disc; posterior margin narrowly pale; areas between punctures on disc somewhat swollen but not calloused; prosternum yellowish brown, conically projecting. Scutellum entirely dark, gradually elevated to posterior with rounded carinate process; meso-and metapleura dark except for ostiolar peritreme whitish yellow. Hemelytron smooth, shiny and transparent with two transverse brown bands; anterior 1/4 and posterior half dark brown; mesal half of posterior end of corium brown, both sides of marking connected with posterior transverse band; posterior part of embolium narrowly brown; posterior part of cuneus and membrane veins tinged with brown. Legs pale yellowish brown; hind femur with apical 1/3 brown or with red band. Abdomen almost entirely dark brown in male, lateral half of segments II, IV  . This tingid species is assumed to be a prey item for the mirid.
Remarks. The male genital structure of this new species is similar to that of S. japonicus except for the shape of the left paramere. Stethoconus takaii can be distinguished from the latter by the following characters. Antennal segment II dark, if middle pale, at least basal 1/3 infuscate (Figs 12-14); areas between punctures on pronotum weakly swollen, but not calloused (30)(31); scutellum weakly elevated and dark without marking (Figs 15-16); pale marking on mesepimeron absent (Figs 17-18); basal part of left paramere somewhat swollen. Some specimens of the new species have been misidentified as S. japonicus (Yasunaga et al. 1997, Nakatani andYasunaga 2001). The description and illustration by Nawa (1910), on which the specific name S. japonicus was based (Schumacher 1917; see also Yasunaga et al. 1996), unequivocally correspond to what has been identified as S. japonicus (with only an apically infuscate antennal segment II and a yellow marking on scutellum).