Omoplax majorcarinae Guilbert, 2001

Souma, Jun, 2025, An illustrated key to the lace bugs (Hemiptera, Heteroptera, Tingidae) from “ Oriental Galapagos ” (the Ogasawara Islands, Japan), with descriptions of three new species of the endemic genus Omoplax Horváth, 1912, ZooKeys 1250, pp. 243-284 : 243-284

Omoplax majorcarinae Guilbert, 2001

Figs 1 G , 2 G , 3 G , 4 G , 5 G , 6 G , 7 G , 8 G , 9 G , 10 G , 11 G , 12 G , 13 G , 14 G , 16 G – I

Omoplax majorcarinae Guilbert, 2001: 551. Holotype: ♂; type locality: Japan • Bonin Islands, Chichijima, Chuo san [= Ogasawara Islands, Chichijima Group, Chichijima Island, Mt. Chuosan]; Bernice P. Bishop Museum, Honolulu, Hawaii, USA.

Omoplax desecta ( Horváth, 1912): Souma and Kamitani (2021: 8) (distribution: part); Souma (2022 a: 125) (distribution: part); Shimamoto and Ishikawa (2023: 94) (catalog: part). Misidentifications.

References.

Yamada and Tomokuni (2012: 198) (monograph); Yamada and Ishikawa (2016: 432) (checklist: Japan); Shimamoto and Ishikawa (2023: 94) (catalog: part).

Material examined.

Non-types, Japan • 1 ♂; Ogasawara Isls., Ototojima Is.; 8 Jul. 1994; Y. Kaneko leg.; referring to Souma and Kamitani (2021); TUA • 3 ♂♂; Ogasawara Isls., Ototojima Is.; 2 Aug. 1996; T. Matsumoto leg.; referring to Souma (2022 a); NSMT • 1 ♂; Ogasawara Isls., Anijima Is., Mt. Togari ; 29 Jul. 2021; T. Matsumoto & S. Shimamoto leg.; SIHU • 1 ♀; Ogasawara Isls., Chichijima Is., Tsurihama ; 10 Feb. 2024; Y. Hisasue leg.; SIHU • 1 ♀; Ogasawara Isls., Chichijima Is., Shigureyama ; 9 Mar. 2024; Y. Hisasue leg.; SIHU • 2 ♂♂ 1 ♀; Ogasawara Isls., Chichijima Is., Mt. Mikazuki ; 5 May 2024; N. Tsuji leg.; SIHU • 1 ♂; Ogasawara Isls, Chichijima Is., Mt. Mikazuki ; 17 May 2024; Y. Hisasue leg.; SIHU • 1 ♀; same locality data as for preceding; 20 Aug. 2024; Y. Hisasue leg.; SIHU • 2 ♀♀; Ogasawara Isls., Ototojima Is., Ainosawa ; 3–4 Jul. 2024; N. Tsuji leg.; SIHU • 1 ♂; Ogasawara Isls., Anijima Is., Mt. Maruyama ; 9 Jul. 2024; Y. Hisasue leg.; SIHU • 1 ♀; Ogasawara Isls., Ototojima Is., Mt. Sokuryogatake ; 12 Jul. 2024; Y. Uehara leg.; SIHU • 1 ♀; Ogasawara Isls., Anijima Is., Mt. Omaru ; 13 Jul. 2024; Y. Hisasue leg.; SIHU • 2 ♀♀; Ogasawara Isls., Chichijima Is., Hatsuneura ; 28 Jul. 2024; N. Tsuji leg.; SIHU • 1 ♂; Ogasawara Isls., Chichijima Is., Mt. Yoake ; 4 Aug. 2024; Y. Hisasue leg.; SIHU • 1 ♀; Ogasawara Isls., Chichijima Is., Mt. Nyuto ; 10 Aug. 2024; Y. Hisasue leg.; SIHU • 2 ♀♀ 1 fifth instar nymph; Ogasawara Isls., Ototojima Is., Kurohama – Ichinotani ; Neolitsea sericea var. aurata ; 23 Sep. 2024; J. Souma leg.; SIHU • 3 ♂♂ 2 ♀♀; same locality, host plant, and collector data as for preceding; 5 Oct. 2024; SIHU • 2 ♂♂ 2 ♀♀; Ogasawara Isls., Anijima Is., Tamana Beach – Mt. Mikaeri ; Neolitsea sericea var. aurata ; 24 Sep. 2024; J. Souma leg.; SIHU • 2 ♂♂ 4 ♀♀; Ogasawara Isls, Ototojima Is., Shikahama – Mt. Hirone ; 27 May 2025; S. Shimamoto leg.; SIHU • 5 ♂♂ 2 ♀♀; Ogasawara Isls, Nishijima Is.; 7 Jun. 2025; Y. Hisasue leg.; SIHU • 1 ♀; Ogasawara Isls, Ototojima Is., Ichinotani ; 9 Jun. 2025; Y. Hisasue leg.; SIHU . The single nymph recorded above is in poor condition and is thus not described in the present study.

Diagnosis.

Omoplax majorcarinae is recognized among the other Omoplax species based on a combination of the following characteristics: rostrum reaching middle part of mesosternum (Fig. 11 G ); pronotal disc pale brown (Figs 3 G , 4 G , 5 G , 6 G ); hood more than 0.5 times as wide as maximum width of head across compound eyes, not reaching apex of clypeus (Fig. 14 G ); paranotum without areolae in middle part, with areolae in remaining parts; anterior margin of hemelytron strongly curved downward in apical half (Figs 7 G , 8 G , 9 G , 10 G ); subcostal and discoidal areas of hemelytron united; costal area narrower than fused subcostal and discoidal areas; Sc (subcosta) vein of hemelytron indistinct in apical part of dorsal view; R + M (fused radius and media) vein of hemelytron indistinct, not carinate; and ventral surface of body dark brown to black (Figs 12 G , 13 G ).

Remarks.

The above specimens matched well with the original description and the illustrations of Omoplax majorcarinae ( Guilbert 2001) in terms of their morphological characteristics, especially body size, coloration, rostral length, and the shape of the paranotum and hemelytron, which are not consistent with the specimens recorded as O. majorcarinae in the previous studies ( Souma and Kamitani 2021; Souma 2022 a): body length with hemelytra 3.10–3.45 mm (3.45 mm in type material) (Figs 1 G , 2 G ); maximum width of body across hemelytra 1.65–1.95 mm (1.85 mm in type material); rostrum reaching middle part of mesosternum (Fig. 11 G ); pronotal disc pale brown (Figs 3 G , 4 G , 5 G , 6 G ); paranotum without areolae in middle part, with areolae in remaining parts (Fig. 14 G ); anterior margin of hemelytron strongly curved downward in apical half (Figs 7 G , 8 G , 9 G , 10 G ); and Sc (subcosta) vein of hemelytron indistinct in apical part of dorsal view. Therefore, the examined specimens were identified as O. majorcarinae . Morphological differences between O. majorcarinae and the six other Omoplax species are presented in the identification key below.

Distribution.

Japan: Ogasawara Islands: Chichijima Group (Anijima Island, Chichijima Island, Nishijima Island, Ototojima Island) (Fig. 19 ) ( Guilbert, 2001; Souma and Kamitani 2021; Souma 2022 a). Omoplax majorcarinae is endemic to Chichijima Group and is newly recorded from Anijima and Nishijima islands.

Host plant.

Only Neolitsea sericea var. aurata ( Lauraceae ) (Fig. 17 I ), which is also known as “ Kinshokudamo ”, was confirmed as a host plant for Omoplax majorcarinae by the field and captive observations of adults and nymphs, suggesting the possibility of monophagy for this lace bug species. However, no feeding behavior of O. majorcarinae was observed on Cinnamomum sp. ( Lauraceae ) or Ligustrum sp. ( Oleaceae ), from which only a single adult was collected in a previous study ( Guilbert 2001). Therefore, these two tree species do not appear to be host plants for this lace bug species.

Bionomics.

Omoplax majorcarinae inhabits an evergreen broad-leaved forest with a subtropical climate in the Ogasawara Islands ( Souma and Kamitani 2021) and sucks sap on the abaxial side of the leaves of Neolitsea sericea var. aurata , causing irregular yellowing on the adaxial side (Fig. 17 I ). Adults were collected in February, March, and from May to October ( Guilbert 2001; Souma and Kamitani 2021; Souma 2022 a); a single nymph was collected in September.

Figures

Figure 1. Males of seven tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 2. Females of eight tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 3. Male pronota of seven tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 4. Female pronota of eight tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 5. Male pronota of seven tingid species endemic to the Ogasawara Islands, Japan, dorsolateral view. A. Acanthomoplax tomokunii B. Omoplax desecta C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 6. Female pronota of eight tingid species endemic to the Ogasawara Islands, Japan, dorsolateral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 7. Male hemelytra of seven tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 8. Female hemelytra of eight tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 9. Male hemelytra of seven tingid species endemic to the Ogasawara Islands, Japan, dorsolateral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 10. Female hemelytra of eight tingid species endemic to the Ogasawara Islands, Japan, dorsolateral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 11. Rostra of eight tingid species endemic to the Ogasawara Islands, Japan, ventral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 12. Male terminalia of seven tingid species endemic to the Ogasawara Islands, Japan, ventral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae.

Figure 13. Female terminalia of eight tingid species endemic to the Ogasawara Islands, Japan, ventral view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis.

Figure 14. Line drawings of pronota of eight tingid species endemic to the Ogasawara Islands, Japan, dorsal view. A. Acanthomoplax tomokunii; B. Omoplax desecta; C. O. hisasuei sp. nov.; D. O. inugusu sp. nov.; E. O. karubei; F. O. kobugashi sp. nov.; G. O. majorcarinae; H. O. mukojimensis. Abbreviations: ca, calli; co, collar; fs, frontal spine; ho, hood; mc, median carina; ms, median spine; os, occipital spine; pa, paranotum; pd, pronotal disc; pp, posterior process.

Figure 16. Living individuals of three tingid species endemic to the Ogasawara Islands, Japan. A. Omoplax inugusu sp. nov., male; B. O. inugusu sp. nov., female; C. O. kobugashi sp. nov., male; D. O. kobugashi sp. nov., female; E. O. kobugashi sp. nov., fifth instar nymph; F. O. kobugashi sp. nov., fourth instar nymph; G. O. majorcarinae, male; H. O. majorcarinae, female; I. O. majorcarinae, fifth instar nymph.

Figure 17. Host plants of seven tingid species endemic to the Ogasawara Islands, Japan. A. Machilus kobu from Ototojima Island, damaged by Acanthomoplax tomokunii; B. M. thunbergii planted in northern Honshu, damaged by A. tomokunii in captivity; C. Rhaphiolepis indica var. tashiroi from Chichijima Island, damaged by Omoplax desecta; D. Calophyllum inophyllum from Chichijima Island, damaged by O. desecta; E. Neolitsea sericea var. aurata Hahajima Island, damaged by O. hisasuei sp. nov.; F. M. boninensis from Hahajima Island, damaged by O. inugusu sp. nov.; G. R. indica var. tashiroi from Mukojima Island, damaged by O. karubei (photographs taken by Jinhyeong Park); H. M. kobu from Chichijima Island, damaged by O. kobugashi sp. nov.; I. N. sericea var. aurata Ototojima Island, damaged by O. majorcarinae.

Figure 19. Collection sites of six tingid species endemic to the Ogasawara Islands, Japan. Red-filled areas = localities based on the present study only; blue-filled areas = localities based on the previous and present studies; green-filled areas = localities based on the previous studies only. The map was created with map data provided by the Geospatial Information Authority of Japan (GSI) (https://maps.gsi.go.jp).