Aneurus taterasanus Shimamoto, 2022

Shimamoto, Shusuke & Ishikawa, Tadashi, 2022, A new species of the flat bug genus Aneurus from Japan (Hemiptera: Heteroptera Aradidae), Zootaxa 5141 (4), pp. 385-393 : 386-392

Aneurus taterasanus Shimamoto & Ishikawa, sp. nov.

( Figs. 1–15 , 20, 21 )

Type material. Holotype: (♂), Japan, Tsushima Is., Tsushima-shi, Izuhara-machi, Tsutsu , Nishitatera-rindô, 10 VI 2019, Shusuke Shimamoto , TUA. Paratypes (75♂♂ 92♀♀): JAPAN: Tsushima Is. : 1♂ 1♀, as holotype, TUA; 1♀, Izuhara-machi, Tsutsu, Nishitatera-rindô , 14.IX.2017, Shusuke Shimamoto,TUA ; 7♂♂ 12♀♀, Kamiagata-chô, Sago, Mt. Mitake , 13.IX.2017, Shusuke Shimamoto, TUA ; 1♂ 2♀♀, Kamiagata-chô, Sago, Mt. Mitake , 13.IX.2017, Rino Fukaya, TUA . Kyushu: 27♂♂ 26♀♀, Miyazaki Pref., Higashimorokata-gun, Aya-chô, Minamimata , 15. VII.2019, Shusuke Shimamoto, TUA ; 2♂♂ 2♀♀, Kagoshima Pref., Kimotsuki-chô, Hoyoshi-dake , 19. III.2017, Reo Ito, TUA ; 2♂♂ 2♀♀, Kagoshima Pref., Kimotsuki-chô, Mt. Hoyoshi-dake , 8. V.1994, M. Hirano, TUA . Shikoku: 1♀, Kochi Pref., Mihama-mura, Imano-yama , 12. IV.1998, T. Befu, TUA . The Ryukyus: Yakushima Is.: 1♀ , Yudomari, Yudomari-Hodô Trail , 25.X.2019, Shusuke Shimamoto, TUA ; 18♂♂ 31♀♀, Anbô, Mt. Mae-dake , 8. VII.2019, Shusuke Shimamoto, TUA ; 1♂ 2♀♀, Ôkawa-rindô , 20–21. IV.1981, Yoshinori Syôno, TUA and YS ; 1♂ 3♀♀, Anbô-rindô , 22–23. IV.1981, Yoshinori Syôno, TUA ; Amami Oshima Is.: 4♂♂ 2♀♀ , Amami-shi, Nazechinaze , 1. VII.2016, Shusuke Shimamoto, TUA ; 1♀, Amami-shi, Nazechinaze , 14.IX.2018, Shusuke Shimamoto, TUA ; 2♂♂ 1♀, Sumiyô-chô , Amami-chûô-rindô, 15.IX.2018, Shusuke Shimamoto, TUA ; 2♂♂, Sumiyô-chô, Amamichûô-rindô , 15.IX.2018, Naoya Ito, TUA ; 6♂♂ 2♀♀, Sumiyô-chô, Kawauchi, nr. Funangyo-no-taki Fall , 14.IX. 2018, Shusuke Shimamoto, TUA ; 1♂ 2♀♀, Uken-son, Chûô-rindô , 4. III.1987, Yoshinori Shono, TUA .

Description. Male. Body ( Figs. 1–2 ) reddish to dark brown; macropterous. Head approximately as long as width across eyes; genae visible in dorsal view, not produced beyond tip of clypeus; clypeus reaching about 2/3 of antennal segment I; antenniferous tubercles acute at apex; postocular lobes subangular, not reaching level of outer margin of eye in dorsal view; rostrum not reaching level of posterior margin of eyes in ventral view. Antennae 2.4 times as long as width across eyes, approximate proportion of segment I to IV 1.0: 1.2: 1.3: 1.9.

Pronotum 2.4 times as wide as its length on midline, as long as head (without neck) on midline; anterior lobe narrower than posterior lobe, with nebulose callosities; lateral margins of anterior lobe strongly sinuate; anterolateral angles rounded, projected beyond collar; posterior lobe provided with a pair of belts of small, shining tubercles; lateral margins of posterior lobe almost straight, serrulate, sometimes with a small process medially. Scutellum subtriangular, 0.6 times as long as its basal width, with lateral margins sinuate and apically rounded; sublateral ridges reaching middle of scutellum. Hemelytra reaching at least basal half of mediotergite VII; corium reaching basal 2/3 of scutellum; clavus longer than corium; membrane punctured, shining, with a scabrous, yellowish brown spot at base.

Abdomen ( Figs.5–6 ) 1.4times as long as its maximum width;posterolateral angles of dorsal external laterotergites II to VI slightly protruding; dorsal external laterotergite VII rounded posterolaterally. Spiracles II and VII lateral, visible in dorsal view, spiracles III to VI ventral, and spiracle VIII terminal. Dorsum ( Fig. 5 ): Mediotergites I and II fused with each other, forming mediotergite I+II; mediotergites III to VI fused with one another; lateral rugose strips narrow, not reaching anterior margin of mediotergite III; dorsal external laterotergites II and III fused internally, forming contergite; contergite relatively small, not reaching anterior 1/3 of dorsal external laterotergite III; paratergite thin, clavate, rounded posteriorly, reaching basal 2/3 of pygophore. Venter ( Fig. 6 ): Additional lateral sclerite triangular, completely separated from other sclerites; ventral laterotergites III to VI separated from each sternum by a sublateral sulcus; ventral hems III to VI separated from each ventral laterotergite by a sublateral fold.

Pygophore ( Fig. 9 ) pyriform, scabrous, distinctly produced over dorsal external laterotergite VII, with lateral margin sinuate; pygophore length from basal carina to posterior end 1.1 times as long as pygophore width. Parameres ( Figs. 10–11 ) long diamond-shaped, relatively wide, approximately 3 times as long as its maximum width, dorsally concave in apical half, medially expanded, covered with a few long and short setae on expanded part. Phallus ( Figs. 12–15 ) long and slender in everted condition; phallotheca sclerotized; endosoma membranous, long, straight, weakly broad and echinate at base; apical part of endosoma with 3 membranous processes, one projected dorsally without spine and others projected laterally with a spine.

Female ( Figs. 3–4 , 7–8 ). Generally similar to male, relatively larger than male; sternum VI provided with a pair of submedian ridges; ventral laterotergite VII completely separated from sternum VII at basal 2/3 by sublateral sulcus; paratergite VIII subangular at posterior angles, nearly reaching apex of paratergite IX; paratergite IX widely rectangle-shaped, with posterior margin concave.

Measurements [in mm, ♂♂ (holotype and paratypes, n=21; holotype in parentheses) / ♀♀ (paratypes, n=20)]. Body length 4.62–5.42 (5.28) / 4.77–5.76; head length 0.48–0.63 (0.62) / 0.62–0.67, width across eyes 0.46–0.60 (0.51) / 0.48–0.53; length of antennae 1.10–1.21 (1.21) / 1.13–1.24; pronotum length 0.51–0.58 (0.58) / 0.55– 0.62, width 1.27–1.43 (1.43) / 1.38–1.50; scutellum length 0.60–0.69 (0.69) / 0.67–0.74, width 1.04–1.17 (1.17) / 1.17–1.24; abdomen length 2.48–3.04 (2.94) / 3.08–3.22, width 1.75–2.16 (2.12) / 1.89–2.39; pygophore length 0.41–0.46 (0.46), width 0.39–0.41 (0.41).

Etymology. The specific name is named after the sacred mountain of Tsushima Island, Mt. Tatera-san where a virgin forest has been conserved as an object of worship, referring to the environs of the collection site of the holotype ( Fig. 16 ); an adjective.

Distribution. Japan: Tsushima Island, Kyushu, Shikoku, the Ryukyus (Yakushima Island, Amami Oshima Island) ( Fig. 22 ).

Biology. This new species inhabits laurel forests where a rich natural environment has been preserved. The type specimens were collected from under the bark of unidentified dead broad-leaved trees ( Fig. 17 ). Some of the observed individuals formed a large group that was composed of all developmental stages ( Figs. 18–19 ), but a small number of them were found individually ( Figs. 20–21 ). Specimens were occasionally found with the following other aradid species: Paraneurus hainanensis (Kormilev, 1968) , Neuroctenus taiwanicus Kormilev, 1955 , and Brachyrhynchus taiwanicus (Kormilev, 1957) . Adults and nymphs of the new species were found from spring to fall, and eggs and first-instar nymphs in July ( Fig. 19 ).

Subgeneric placement. Three subgenera have been recognized in the genus Aneurus by Heiss(1998a): Aneurodes Heiss, 1998 , Neaneurus Heiss, 1998, and the nominotypical Aneurus . Having a combination of the morphological characteristics such as the relatively large contergite, the relatively wide parameres, and the abdominal dorsum lacking any spine, the new species A. taterasanus sp. nov. is undoubtedly classified into the subgenus Aneurodes . The new species is the first documented occurrence of Aneurodes in Japan.

Comparative notes. In the subgenus Aneurodes , four species, all from the Palaearctic Region, have been known prior to this study. This new species, A. taterasanus sp. nov., is distinguished from these species by a combination of the following characteristics: antenniferous tubercle acute at apex; hemelytron with a yellowish brown marking ( Figs. 1, 3 , 20–21 ); spiracles II and VII lateral, visible in dorsal view, III to VI ventral, and VIII terminal ( Figs. 6, 8 ); contergite relatively small ( Figs. 5, 7 ); and pygophore pyriform ( Fig. 9 ).

Species of the subgenus Aneurodes are very similar in overall morphology to those of the genus Paraneurus , therefore the latter genus might be closely related to the genus Aneurus to which Aneurodes belongs. The only difference between Aneurodes and Paraneurus is apparently the presence of a contergite in Aneurodes , which is absent in Paraneurus . Since the contergite is almost impossible to observe with the wings closed, determining a given specimen belongs to Aneurodes or Paraneurus is often more difficult than the identification of species of Aneurodes . Therefore, a comparison between this new species, the Japanese P. nipponicus (Kormilev & Heiss, 1976) and the Taiwanese P. bimaculatus (Kormilev & Heiss, 1977) , which are particularly similar in appearance, is also discussed here. The new species is distinguished from them by the following characters: pronotum with a slightly incurved anterior border, anteriorly projected anterolateral angles, strongly sinuate lateral margins of the anterior lobe (vs. straight anterior border, anterolateral angles not projected, weakly sinuate lateral margins of the anterior lobe); pyriform pygophore (vs. acorn-shaped pygophore) ( Fig. 9 ); and a slightly larger body size (4.6–5.8 mm; vs. 4.5–5.0 mm). Incidentally, the yellowish brown markings on the hemelytra are often difficult to observe because the oil emitted from the specimen discolors the body surface after death.

Remarks. Our description and illustration of the everted phallus of the new species A. taterasanus sp. nov. is the first documentation of these structures for a representative of the subfamily Aneurinae ( Figs. 12–15 ). The structure, although apparently simpler, is similar to that of other species of Aradidae as illustrated by previous studies ( Heiss 2007, Leston 1955, Usinger & Matsuda 1959, Yang 2004). The endosoma, including the shape and number of membranous processes and sclerotized spines, did not show any significant intraspecific variability among the specimens observed. The structure of the phallus may potentially be useful for species identification in Aneurus and its related genera and they deserve further study.

As mentioned above, species of the subgenus Aneurodes (or the genus Aneurus ) and the genus Paraneurus are very similar to one another in morphology, except for the presence or absence of the contergite, so it seems questionable whether it is justified to define Aneurodes and Paraneurus by this difference alone. A detailed study of the structure of the phallus of the species of both genus group taxa may be helpful for their redefinition.

Figures

FIGURE 22. Distribution of Aneurus taterasanus sp. nov. Holotype locality=red circle, paratype localities=blue triangle.

FIGURES 1–4. Aneurus taterasanus sp. nov., male (1–2) and female (3–4), dorsal (1, 3) and ventral (2, 4) views.

FIGURES 5–8. Abdomen of Aneurus taterasanus sp. nov., male (5–6) and female (7–8), dorsal (5, 7) and ventral (6, 8) views.

FIGURES 9–11. Aneurus taterasanus sp. nov. 9, Pygophore, dorsal view; 10–11, right paramere, dorsal view (10) and rightlateral (11) views.

FIGURES 12–13. Everted and inflated phallus of Aneurus taterasanus sp. nov., dorsal (12) and lateral (13) views.

FIGURES 14–15. Everted and inflated phallus of Aneurus taterasanus sp. nov., dorsal (14) and lateral (15) views.

FIGURES 16–21. Habitats and/or living individuals of Aneurus taterasanus sp. nov. 16, A forest on Mt. Tatera-san of Tsushima Island, from which the holotype was collected; 17, a dead broad-leaved tree in a forest of Yakushima Island, the area surrounded by the white line is shown in Figs. 18 and 19; 18, a group of individuals under the bark of a dead broad-leaved tree shown in Fig. 17; 19, a group of eggs, first instar nymphs and adults under the bark of a dead broad-leaved tree shown in Fig. 17; 20–21, a living adult female, dorsolateral (20) and dorsal (21) views.