The assassin bug subfamily Tribelocephalinae (Hemiptera: Heteroptera: Reduviidae) from Japan, with descriptions of eight new species in the genera Opistoplatys and Abelocephala Author Ishikawa, Tadashi Author Cai, Wanzhi Author Tomokuni, Masaaki text Zootaxa 2015 3936 2 151 180 journal article 10.11646/zootaxa.3936.2.1 e202312c-4686-47ed-bbd2-d470a62d5e4a 1175-5326 241991 157EDA4A-00A3-469F-8234-7E7175BF13E7 Abelocephala nakatai sp. nov. ( Figs. 45, 46 , 57, 58 , 67 , 72 , 78 , 93–98 , 116 , 122 , 128, 134, 140, 146, 151) Diagnosis. This species is recognized by the following combination of character states: body approximately 3 mm long; head 1.3 to 1.4 times longer than width across eyes; mandibular plate acutely angled at anterior corner and strongly projected anteriorly in dorsal view, rostral segment I approximately 1.7 times longer than segment II; posterior pronotal lobe yellowish brown; outer (larger) cell of hemelytral membrane rounded apically; and posterior process of pygophore narrow with rounded apical margin in dorsal view. Description. Male (macropterous) . Body ( Fig. 45 ) mostly brownish. Antennae, rostrum, and legs brownish yellow. Antennal flagella pale yellow. Posterior pronotal lobe yellowish brown except for median longitudinal sulcus and posterior marginal area brown. Hemelytra dark brown, with basal part pale yellow to pale brown; corial cell more or less fuscous ( Fig. 45 ). Abdomen yellowish brown to brown. Head ( Figs. 45 , 55, 56 , 72 ) approximately 1.3 times longer than width across eyes, as long as pronotum, protuberant immediately behind eyes in dorsal view; anteoculus as long as postoculus; mandibular plate ( Fig. 58 ) acutely angled at anterior corner and strongly projected anteriorly in dorsal view. Eye ( Figs. 57 , 72 ) approximately 0.4 times as wide as interocular space in dorsal view. Antennal segment I slender, approximately 7 times longer than its maximum width, slightly longer than segment II ( Figs. 93, 94 ); flagellum as long as segment I ( Fig. 95 ). Rostral segment I stout, 1.7 times longer than segment II ( Fig. 72 ). Pronotum ( Fig. 45 ) approximately 0.7 times as long as humeral width; anterior lobe 0.55 times as long as posterior lobe along midline, 0.7 times as wide as humeral width. Hemelytron ( Figs. 45 , 116 ) wide, 2.2 times longer than its maximum width, exceeding apex of abdomen by approximately 0.3 times of its length; outer (larger) cell of membrane ( Fig. 116 ) rounded apically. Pygophore ( Fig. 122 ) ovoid in lateral view; posterior process (Fig. 128) narrow, slightly tapering apicad, with rounded apical margin in dorsal view. Parameres ( Fig. 134 ) strongly curved in apical two-thirds, with rounded, inwardly projected apex in dorsal view. Struts of phallus ( Fig. 140 ) tapering apicad, weakly constricted at apical one-third, obtuse at apex, and with lateral walls thinned throughout in dorsal view. Female (macropterous) . Almost same as male in general habitus ( Fig. 46 ). Head ( Figs. 46 , 67 , 78 ) approximately 1.4 times longer than width across eyes. Antennal segment I stouter and much shorter than that of male, approximately 5 times longer than its maximum width, as long as segment II ( Figs. 96, 97 ); flagellum approximately 1.2 times longer than segment I ( Fig. 98 ). Abdominal tergite IX ( Fig. 146 ) with lateral projection at each basal angle; lateral projection long, gently constricted at middle, obtuse at apex, with weak notch subapically. Valvifer I ( Fig. 151 ) oblong; valvula I ( Fig. 151 ) with approximately 3 setae. Measurements [in mm, ♂ (n=31) /♀ (n=19), holotype in parentheses]. Body length 2.80–3.35/2.95–3.49 (3.00). Head length 0.65–0.74/0.68–0.72 (0.67), width across eyes 0.54–0.62/0.51–0.58 (0.55). Lengths of antennal segments I and II 0.62–0.73/0.51–0.60 (0.69) and 0.60–0.71/0.50–0.56 (0.64), respectively. Lengths of rostral segments I and II 0.49–0.56/0.52–0.56 (0.50) and 0.30–0.32/0.30–0.31 (0.32), respectively. Pronotum length 0.62–0.76/0.61–0.69 (0.67), width across humeri 0.87–1.08/0.89–1.05 (0.94). Hemelytron length 2.41–2.92/ 2.36–2.74 (2.57). Lengths of femur and tibia of fore leg 0.77–0.98/0.79–0.88 (0.90) and 0.80–0.96/0.79–0.86 (0.85); of mid leg 0.75–0.93/0.78–0.87 (0.79) and 0.79–0.95/0.77–0.87 (0.86); of hind leg 0.98–1.24/1.01–1.16 (1.07) and 1.14–1.36/1.05–1.15 (1.21). Abdomen length 1.42–1.83/1.61–1.84 (1.51), maximum width 1.06–1.56/ 1.34–1.55 (1.19). Holotype . ♂ ( Fig. 45 ), “[ JAPAN ] Komi, Iriomote-jima Is., the Ryûkyûs, 23–27.IV.2004 , FIT, T. Ishikawa et al.” ( LETUA IC 2014-00135) ( TUA ). Paratypes ( 30 ♂ , 19 ♀). JAPAN [Ishigaki Is.] Mt. Nosoko-dake: 6 ♂ (one shown in Figs. 55, 56 , 72 , 93–95 , 140 ), 2 ♀, 5.ii.2003 , T. Nakata ( LETUA IC 2014-00136–00143) ( TUA ), 1 ♂ , 1 ♀, 9.vi.2003 , T. Nakata ( LETUA IC 2014-00144–00145) ( TUA ), 1 ♀, 9.vi.2003 , S. Nagashima ( LETUA IC 2014-00146) ( TUA ), 1 ♀ ( Figs. 146 , 151 ), 9.vi.2003 , T. Ishikawa ( LETUA IC 2014-00147) ( TUA ), 1 ♂ , 10.vi.2003 , S. Nagashima ( LETUA IC 2014- 00148) ( TUA ), 1 ♀, 10.vi.2003 , T. Ishikawa ( LETUA IC 2014-00149) ( TUA ), 1 ♂ , 2 ♀, 11.vi.2003 , S. Nagashima ( LETUA IC 2014-00150–00152) ( TUA ), 6 ♀ (each one shown in Fig. 46 and Figs. 67 , 78 , 96–98 ), 11.vi.2003 , T. Ishikawa ( LETUA IC 2014-00153–00158) ( TUA , CAU , NSMT ). Ôtake: 1 ♂ , 24–26.v.2001 , T. Tsuru ( LETUA IC 2014-00159) ( TUA ). Hirakubo: 2 ♀, 14.ii.2003 , T. Nakata ( LETUA IC 2014-00160–00161) ( TUA ). [Iriomote Is.] Ôtomi-rindô: 1 ♂ , 7–11.iv.2005 , FIT-M, J. Kantoh ( LETUA IC 2014-00162) ( TUA ). Komi: 2 ♀, 2.v.2002 , S. Nagashima ( LETUA IC 2014-00163–00164) ( TUA ), 19 ♂ (each one shown in Figs. 116 , 134 and Figs. 122 , 128), 1 ♀, same data as holotype ( LETUA IC 2014-00165–00184) ( TUA , CAU , NSMT ). Distribution. Japan : Ryukyu Islands (Ishigaki Is., Iriomote Is.). Etymology. Named after Mr. Tadafumi Nakata, who collected the type specimens of this species; a noun in the genitive case. Remarks. Only the macropterous form of this species is known. In general habitus, this new species resembles A . albula sp. nov. However, A . nakatai sp. nov. can be distinguished from A . albula sp. nov. by the head protuberant immediately behind the eyes in dorsal view ( Figs. 57 , 67 ) [vs. not protuberant behind the eyes in dorsal view ( Figs. 53 , 65 )], the mandibular plate acutely angled at the anterior corner and strongly projected anteriorly in dorsal view ( Fig. 58 ) [vs. nearly right-angled and weakly projected anteriorly in dorsal view ( Fig. 54 )], the length of rostral segment I [1.7 times longer than segment II ( Figs. 72 , 78 ) vs. 1.4–1.5 times longer than segment II ( Figs. 70 , 76 )], the outer (larger) cell of the hemelytral membrane rounded apically ( Fig. 116 ) [vs. acutely angled apically ( Fig. 114 )], and the posterior process of the pygophore narrow with a rounded apical margin in dorsal view (Fig. 128) [vs. wide with a straight apical margin in dorsal view (Fig. 126)]. Abelocephala nakatai sp. nov. was obtained from the leaf litter of humid forests and from FIT-Ms placed on the forest floor. This new species was found simultaneously with O . minimus sp. nov. in Mt. Nosoko-dake, Ishigaki Island and with A . albula sp. nov. in Komi, Iriomote Island. This observation implies that these three species show the same habitat preference.