Planicapitus luteus Taszakowski, Kim & Herczek, sp. nov.

Distinguished by vertical, flattened head, not punctured but wrinkled and distinctly higher than wide, dorsally extending to level of highest point of pronotum; vertex convex, protruding above eye level; width of vertex slightly larger than eye width; dorsum and pleurites of thorax with deep and dense punctures; calli slightly marked, tarsi two segmented, claw without subapical tooth; labium reaching third abdominal segment; right paramere very small, short, dagger-shaped; left paramere ca. 2.5 times as long as right one.

Male. Body oval, slightly elongated (Fig. 1A). Head clearly higher than wide, dorsally extending to highest point of pronotum, flattened, impunctate but wrinkled; Antenna thin (particularly segments III and IV). Labium reaching third abdominal segment (Fig. 1B). Pronotal collar with row of punctures. Pronotum distinctly punctuate, distinctly carinate at sides, with slightly upturned lateral margins; calli slightly marked, separated by shallow fossa. Scutellum convex, wider than long, baso-medially clearly depressed. Thoracic pleura distinctly punctate (Fig. 1C). Ostiolar peritreme small, strongly convex and covered with fine spines (Fig. 4A–C). Mesofemora with five trichobothria (Fig. 3C, D). Tarsi two segmented, claws without apical tooth (Fig. 3 E–G). Genitalia: genital capsule trapeziform, with two longitudinal sutures at sides (Fig. 5A, B); aedeagus delicate, membranous, with weakly sclerotized dorsal wall of phallotheca, endosoma sacciform and membranous, weakly sclerotized (Fig. 5A, B, E). Left paramere scythe-shaped, sensory lobe with several long setae, apical process elongate (Fig. 5A–C); right paramere very small, short, dagger-shaped (Fig. 5A, B, D).

Figure 1. 

Planicapitus luteus: dorsal (A), ventral (B) and lateral (C) views.

Affiliation of Planicapitus luteus to the Gigantometopini is clearly confirmed by the following features: compound eyes relatively small, significantly separated from each other, pronotum deeply punctate and elongate, calli separated by shallow fossa, pronotal collar demarcated by row of punctures, inflated scutellum, and five mesofemoral trichobothria (Herczek 1993, Yasunaga et al. 2017).

Set of features mentioned in the diagnosis clearly differ the new genus from other genera belonging to Gigantometopini. Planicapitus luteus belongs to the smallest representatives of tribe. The new genus is similar in size to Isometopidea lieweni which body length of the only known specimen equals to 3.0 mm. It is a female, so probably (like other representatives of tribe) males reach a smaller body size (Poppius 1913, Yasunaga 2005, Herczek et al. 2018). Isometopidea further differs from newly described genus by the structure of the head, which is not higher than wide, somewhat rounded and not strongly flattened in front. Sulawesimetopus, the second comparatively small-sized genus of the Gigantometopini, is slightly larger and can be distinguished from the new genus by the three segmented tarsi and punctured head. Other representatives of Gigantometopini are a way larger than the new genus in body size.

Combined from Latin adjective: planus, flat and noun: caput, capitis, head; gender masculine.

See generic diagnosis.

Male. Body shiny, yellow-brownish, covered by semi-erect pale-brown seta (Fig. 1A–C). Head: yellow-whitish, 1.5 times as high as wide, compound eyes reddish yellow, vertex orange, convex, 1.3 times as wide as eye width in dorsal view. Frons whitish, with two small dark brown spots ventrally extending into large Y-shaped brown macula; gena whitish yellow (Figs 1C, 2A, B). Antenna yellowish. Labium shiny, yellowish, segment IV with brown apex (Fig. 1B). Thorax: pronotum yellow, semi-transparent laterally; exposed part of mesoscutum yellow, scutellum yellowish brown, with apex white and lateral angles narrowly whitish, 0.7 as long as wide. Pleura yellowish brown, with red stripe from propleuron to episternum (Fig. 1B, C). Ostiolar peritreme ivory, evaporative area yellow (Fig. 1B, C). Claval commissure 0.6 times as long as scutellum. Hemelytron: in various shades of yellow, median part with two whitish spots. Cuneus 0.9 times as long as wide, yellowish, with white spot in basal inner corner. Membrane pale grey, semi-transparent, with two cells. Legs: coxae pale, almost white, femora yellow-white (Fig. 1B, C), with brown spots, tibiae yellow with dark brown spots, tarsi yellow (Fig. 1B, C). Abdomen: bicoloured, dark brown, except for pale yellow genital segment (Fig. 1B, C). Genitalia: as described above. Measurements: given in the Table 1.

Figure 2. 

Planicapitus luteus: head in frontal view (A), lateral view of head (B), left antenna (C).

From Latin adjective luteus, yellow.

Figure 3. 

Planicapitus luteus: head in dorsal view (A, B), femur of middle leg in ventrolateral view, showing trichobothrial pattern (C, D), pretarsus of foreleg, lateral view (E), tarsus of middle leg, lateral view (F), pretarsus of middle leg, ventral view (G).

Unknown.

Figure 4. 

Scent gland, evaporatory area (A, B) and peritreme (C) of Planicapitus luteus.

Holotype (♂): ‘Borneo, Sabah / Danum Valley / 70km W Lahad Datu / M.J. & J.P. Duffels // East Ridge Trail / 150m / 2.XII.1989 // sample Sab. 53 / understorey rainforest, / at light’. The holotype is deposited in RBINS.

Figure 5. 

Male genitalia of Planicapitus luteus: genital capsule in dorsal (A) and caudal (B) views, left paramere (C), right paramere (D), aedeagus in dorsal view (E).

Bruneimetopus simulans Taszakowski, Kim & Herczek, sp. nov.

Distinguished by vertical, slightly flattened head, not punctured but wrinkled and higher than wide, dorsally not extending to level of highest point of pronotum; vertex slightly convex, protruding above eye level, width of vertex equal to eye width; dorsum and pleurites of thorax with deep and dense punctures; calli slightly marked, tarsi two segmented, claw with very small, barely noticeable apical tooth; labium reaching third abdominal segment, right paramere well developed, with knee-shaped sensory lobe; left paramere ca. 1.5 times as long as right one.

Male. Body oval, slightly elongate (Fig. 6A). Head higher than wide, dorsally not extending to highest point of pronotum, slightly flattened, impunctate but wrinkled. Antenna thin (particularly segments III and IV). Labium reaching third abdominal segment. Pronotal collar with row of punctures posteriorly. Pronotum distinctly punctuate, calli slightly marked, separated by shallow fossa. Scutellum slightly convex, baso-medially clearly depressed. Thoracic pleura distinctly punctate. Ostiolar peritreme small, moderately convex and covered with very fine spines (Fig. 8). Mesofemora with five, metafemora with six trichobothria (Fig. 7F, G). Tarsi two segmented, claws with very small, barely noticeable apical tooth (Fig. 7D, E). Genitalia: genital capsule trapeziform (Fig. 9A), aedeagus delicate, endosoma sacciform and membranous, very weakly sclerotized inside, outer subapical and apical part more sclerotic, clothed with dense spinules (Fig. 9A, D). Left paramere scythe-shaped, sensory lobe with several long setae, apical process elongated (Fig. 9A, B); right paramere left paramere ca. 1.5 times as long as right one, with knee-shaped sensory lobe (Fig. 9C).

Figure 6. 

Bruneimetopus simulans: holotype: dorsal (A), ventral (B) and lateral (C) views.

Affiliation of Bruneimetopus to the Gigantometopini is clearly confirmed by the same set of features as for Planicapitus (see above). It is also indicated by presence of six metafemoral trichobothria (the specimen of Planicapitus luteus is devoid of hindlegs).

As in the case of Planicapitus, set of features mentioned in the diagnosis clearly differ the new genus from other genera belonging to Gigantometopini. The newly described genera are very similar morphologically to each other. However, in addition to small differences in the proportions of body parts and coloration, they can easily be distinguished by the completely different shape and size of the right paramere. This was a premise to describe them in separate genera.

Name combines Brunei (the type locality) with part of the generic name Isometopus, the type genus of the subfamily.

See generic diagnosis.

Male. Body shiny, in various shades of yellow and brown, covered by semi-erect pale brown and brown setae (Fig. 6A–C). Head: brownish yellow, 1.4 times as high as wide, compound eyes reddish, vertex white, slightly convex, as wide as eye in dorsal view. Frons dark brown between eyes, yellowish below inferior margin of eyes; clypeus brown; gena yellow (Fig. 7A–C). Antenna yellowish, segments III and IV darker. Labium shiny, yellowish, segment IV brown (Fig. 6B). Thorax: pronotum dark yellow, lateral margins semi-transparent and slightly raised, slightly wider at front; posterior margin whitish. Exposed part of mesoscutum brown with yellow tinge. Scutellum dark brown, with white apical part and black extreme apex, 0.6 times as long as wide, covered by semi-erect setae. Propleuron dark yellow, meso- and metapleurons dark brown with dark yellow tinge. Ostiolar peritreme ivory, evaporative area yellow-brown (Fig. 4D–F). Claval commissure comparatively long, 0.5 times as long as scutellum. Hemelytron: in various yellow and brown shades: median, posterior part and cuneus in 2/3 of their length semi-transparent, whitish yellow, base of hemelytra and clavus yellow-brown, part neighbouring with cuneal fracture and 1/3 length of cuneus dark brown. Cuneus 0.9 as long as wide. Membrane pale grey, semi-transparent, with two cells. Legs: coxae yellowish pale, femora yellow-white, with brown spots apically, tibiae yellow with four or five dark brown, irregular rings, tarsi yellow (Fig. 6A, B). Abdomen: bicolored: first two segments yellowish to brown, others dark brown (Fig. 6B, C). Genitalia: as described above. Measurements: given in the Table 1.

Figure 7. 

Bruneimetopus simulans: holotype: head in frontal view (A), lateral view of head (B), head in dorsal view (C), tarsus of middle leg, lateral view (D), pretarsus of middle leg, lateral view (E), paratype: femur of middle leg in ventral view, showing trichobothrial pattern (F), femur of hind leg in ventral view, showing trichobothrial pattern (G).

The species name simulans (resembling) is the present participle of the Latin verb simulo (to make like or to assume the appearance of anything), in allusion to the resemblance of this species to Planicapitus luteus.

Figure 8. 

Bruneimetopus simulans (holotype) scent gland, evaporatory area (A, B) and peritreme (C).

Unknown. Two specimens were collected in a mangrove forest (Fig. 10) by a Malaise trap, together with several other specimens of Isometopinae.

Figure 9. 

Male genitalia of Bruneimetopus simulans: holotype: genital capsule in dorsal view (A), left paramere (B), right paramere (C), aedeagus (D).

Holotype (♂): ‘Borneo, Brunei, Tutong // Tutong area, mangroves forest / small stream near water edge, Malaise / trap 1; 16.viii.2014, leg: C. Damken / 4°46'9.54"N, 114°36'20.64"E // ID code: tutong.mangroves.01780’; Paratype (♂):‘Borneo, Brunei, Labu FR. / mangrove forest, Malaise trap ID4 / 06.viii.2018; leg: C. Damken / 4°50'53.11"N, 117°7'45.65"E// ID code: labu.mangroves.01777’. The holotype and paratype are deposited in the UBDM.

Figure 10. 

Malaise trap at the collecting site of holotype of Bruneimetopus simulans.

Distributional remarks

In total, only 49 imagines of Gigantometopini representing eleven species were ever recorded. Four species are known only from the holotype: Gigantometopus rossi, Gigantometopus schuhi, Isometopidea lieweni, and Planicapitus luteus. Below we present the complete checklist of Gigantometopini with distributional records (Fig. 11) and biological information (following Poppius 1913, Schwartz and Schuh 1990, Miyamoto et al. 1996, Yasunaga and Hayashi 1996, Lin and Yang 2004, Yasunaga 2005, Akingbohungbe 2012, Yasunaga et al. 2017, Herczek et al. 2018):

Figure 11. 

Distribution of Gigantometopini: A I. lieweni B G. rossi C G. schuhi and B. simulans D P. luteus E S. henryi F A. formosanus G K. yangi H A. formosanus and I. lieweni nec I A. gryllocephalus J A. gryllocephalus and K. fraxini

Gigantometopini Herczek, 1993

Astroscopometopus Yasunaga & Hayashi, 2002

Astroscopometopus formosanus (Lin, 2004)

Isometopidea formosana Lin, 2004

1♂, Taiwan, Nantou, Chunyang (Fig. 11H), 11 Jun–9 Jul 2002, malaise trap

1♂, Taiwan, Pingtung, Hengchun, Kenting National Park (Fig. 11F), 10 Mar–14 Apr 2005, malaise trap

Astroscopometopus gryllocephalus (Miyamoto, Yasunaga, & Hayashi, 1996)

Isometopidea gryllocephala Miyamoto, Yasunaga, & Hayashi, 1996

1♀, Japan, Ryukyu Arc., Ishigaki Is., Shiramizu (Fig. 11J), 19 Mar 1993, sweeping, grasses growing on the subtropical jungle floor near a montane stream.

1♀, Japan, Ryukyu Arc., Ishigaki Is., Mt. Yarabudake (Fig. 11J), 10 Mar 1999, the bark of the subtropical ash, Fraxinus griffithii

1♂, 8 final instar nymphs, Japan, Ryukyu Arc., Ishigaki Is., Mt. Fukami-Omoto (Fig. 11J), 18 Mar 2000, the bark of the subtropical ash, Fraxinus griffithii

1♀, Japan, Ryukyu Arc., Iriomote Is. (Fig. 11I), 2 Mar 2002, root of an unidentified broadleaved tree

Gigantometopus Schwartz & Schuh, 1990

Gigantometopus rossi Schwartz & Schuh, 1990

1♀, Indonesia, Sumatra, Sumatera Barat, Mangani, mine near Kota Tinggi, 700 m a.s.l. (Fig. 11B), 20 Jul 1983

Gigantometopus cf. rossi Schwartz & Schuh, 1990

1♀, South India

Gigantometopus schuhi Akingbohungbe, 2012

1♂, Brunei, Borneo, Bukit Sulang near Lamunin (Fig. 11C), 20 Aug–10 Sep 1982, insecticide fogging on Shorea macrocarpa

Isometopidea Poppius, 1913

Isometopidea lieweni Poppius, 1913

1♀, Sri Lanka, Anuradhapura (Fig. 11A), 21 Dec

Isometopidea lieweni nec Poppius, 1913

1♀, Taiwan, Nantou, Lienhachi (Fig. 11H), Nov 1984, malaise trap

Kohnometopus Yasunaga, 2005

Kohnometopus fraxini Yasunaga, 2005

1♂, Japan, Ryukyu Arc., Ishigaki Is., Mt. Fukami-Omoto (Fig. 11J), 28 Sep 2002; 6♀♀, 22 May 2002

1♀, Japan, Ryukyu Arc., Ishigaki Is., Mt. Yarabudake (Fig. 11J), 1 Jun 2002; 2♂♂, 6♀♀, 28 Nov 2002; 1♀, 2 Oct 2002; all specimens of this species were collected on two trees of Fraxinus griffithii

Kohnometopus yangi (Lin, 2005)

Isometopidea yangi Lin 2005

1♂, Taiwan, Taitung, Peinan Panchiu Station (Fig. 11G), 19 Nov–16 Dec 2004, malaise trap; 2♂♂, 2♀♀, 19 Nov–16 Dec 2004, malaise trap; 1♀, 7 Oct–19 Nov 2004, malaise trap; 3♂♂, 1♀, 16 Dec 2004–17 Feb 2005, malaise trap

Sulawesimetopus Herczek, Gorczyca & Taszakowski, 2018

Sulawesimetopus henryi Herczek, Gorczyca & Taszakowski, 2018

3♂♂, Indonesia, Sulawesi Utara (Fig. 11E), 8–18 Nov 1985

5♂♂, 1♀, Indonesia, Sulawesi Utara, Dumonga-Bone National Park, Hogg’s Back Subcamp, 660 m. a.s.1. (Fig. 11E), 15 Nov 1985

Planicapitus Taszakowski, Kim & Herczek, gen. nov.

Planicapitus luteus Taszakowski, Kim & Herczek, sp. nov.

1♂, Malaysia, Borneo, Sabah Danum Valley, East Ridge Trail, 150 m. a.s.1., (Fig. 11D), 2 Dec 1989, understorey rainforest, at light

Bruneimetopus Taszakowski, Kim & Herczek, gen. nov.

Bruneimetopus simulans Taszakowski, Kim & Herczek, sp. nov.

1♂, Brunei, Borneo, Tutong area (Fig. 11C), 16 Aug 2014, mangroves forest (Fig. 10), malaise trap

1 ♂, Brunei, Borneo, Labu FR. (Fig. 11C), 6 Aug 2018, mangroves forest, malaise trap