Lyctocoris ichikawai Yamada & Yasunaga

Yamada, Kazutaka, Yasunaga, Tomohide & Ichikawa, Toshihide, 2012, A new species of Lyctocoridae (Hemiptera: Heteroptera: Cimicoidea) feeding on the exuded sap of Sawtooth Oak, Quercus acutissima, in Japan, Zootaxa 3525, pp. 65-74 : 67-71

Lyctocoris ichikawai Yamada & Yasunaga , sp. nov.

( Figs. 1–22 )

Diagnosis. Distinguished from congeners by the following combination of characters: hemelytra blackish brown with pale yellow markings on basal and median part of clavus, basal part of endocorium, apical part along claval suture and medial fracture in endocorium, and basal part of embolium; membrane smoky dark brown, but subbasal area and area along four veins always semitransparent; labium reaching metasternum; parameres strongly acute at apex; left paramere apically not bent inwardly; genital apophysis rounded at apex, constricted near middle, broadened at base.

Description. Coloration. Body ( Figs. 1 , 20 ) generally blackish brown. Head ( Figs. 1, 3 ) blackish brown, apex tinged with pale brown; eyes reddish brown; ocelli red to reddish brown. Antennae ( Figs. 1, 3 ) generally fuscous, basal half of segment II tinged with yellowish brown. Labium ( Fig. 2 ) yellowish brown; segment I and II blackish brown. Pronotum ( Figs. 1, 3 ) blackish brown, with posterior margin narrowly pale yellow. Scutellum ( Fig. 1 ) same color as pronotum, with apex pale yellow. Hemelytra ( Fig. 1 ) blackish brown; basal and median part of clavus, basal part of endocorium, apical part along claval suture and medial fracture in endocorium, and basal part of embolium with pale yellow markings; membrane smoky dark brown, but subbasal area and area along four veins always semitransparent. Venter of thorax generally blackish brown. Ostiolar peritreme and evaporatorium ( Figs. 2, 4 ) fuscous. Legs ( Fig. 2 ) blackish brown; coxa brown; trochanter and basal and apical femur pale yellow. Abdomen ( Fig. 2 ) brown to blackish brown; side of each sternum tinged with reddish brown.

Structure. Body ( Fig. 1 ) oval, densely covered with short, silky, recumbent setae. Head ( Figs. 1, 3 , 10 ) excluding neck about 0.75 times as long as width across eyes, dorsal surface shining; anteocular portion about 0.7 times as long as length of eye in dorsal view; vertex about 1.5 times as wide as width of eye in dorsal view; postocular portion constricted; neck very short; ocelli placed between the eyes, anterior of an imaginary line that passes through the posterior margin of eyes. Antennal segment I ( Figs. 1, 3 , 10 ) reaching apex of head, sparsely covered with short recumbent setae; segment II ( Figs. 1, 3 , 10 ) about 0.75 times as long as head width across eyes, slightly thickened toward apex, covered with suberect setae, each seta about as long as width of the segment; segments III and IV ( Figs. 1, 3 , 10 ) covered with long erect setae intermixed with short recumbent setae, longest seta about twice as long as width of respective segment; segment IV ( Figs. 1, 3 , 10 ) weakly flattened, slightly longer than segment III. Labium reaching metasternum; segment III about 2.8 times as long as segment II; segment IV slightly longer than segment II. Pronotum ( Figs. 1, 3 , 10 ) trapezoidal, shining; anterior half weakly swollen; posterior half shallowly depressed medially; anterior margin nearly straight, width slightly narrower than mesal length; lateral margin carinate, strongly rounded at anterior angle; posterior margin concave, width about 2.8 times as wide as anterior pronotal width; collar indistinct. Scutellum ( Fig. 1 ) shining, about 0.7 times as long as basal width, shallowly punctate on basal half, rugose on apical half. Hemelytra ( Figs. 1 , 11 ) discernibly narrowed toward apex, densely covered with short, silky, recumbent setae and tiny punctures; embolial margin about 1.8 times as long as cuneal margin; maximum width of endocorium about 1.5 times width of embolium; membrane with four distinct veins, middle two veins slightly curved. Ostiolar peritreme ( Figs. 4 , 6 ) sharply bending at middle and gradually narrowed anteriad, slightly expanding posteriad at the bend, extending to anterior margin of metapleuron. Fore and mid coxae with several spine-like setae around apex; fore trochanter with brush-like setae on ventral side; fore tibia ( Fig. 12 ) with 23–26 small teeth on ventral side and a few stout spines on apical half, and with large fossula spongiosa at apex; mid tibia ( Fig. 13 ) with 22–23 small teeth on ventral side, apically with fossula spongiosa smaller than that of fore tibia; mid and hind tibiae ( Figs. 13, 14 ) covered with short suberect setae intermixed with several stout spines about as long as width of respective tibia. Abdomen densely covered beneath with short, silky recumbent setae; scissure on abdominal tergite reaching to posterior margin of segment III.

Male genitalia ( Figs. 5 , 7–9 , 15–18 ): Pygophore ( Fig. 15 ) densely furnished with short erect setae on posterodorsal and posteroventral surface. Parameres ( Figs. 16, 17 ) strongly acute at apex; left paramere curved at middle, apically not bent inwardly, moderately rounded on outer margin, weakly serrate on inner side of apical half; right paramere about half the length of left paramere, weakly serrate on inner side. Phallobase ( Fig. 18 ) symmetrical, with a hole at anterior 1/3, slightly narrowed anteriad, deeply emarginate inwardly on posterior margin. Aedeagus ( Figs. 5 , 7, 8 ) very long, strongly coiled upwardly, apically with long and straight acus.

Female genitalia ( Fig. 19 ): Genital apophysis ( Fig. 19 ) rounded at apex, reaching anterior margin of sternum VI, constricted near middle, broadened at base.

Measurements [3 (n=10)/ Ƥ (n=10), value for holotype male in parentheses]. Body length 4.50–4.85 (4.85)/ 4.55–5.05; head length (excluding neck) 0.58–0.70 (0.64)/ 0.64–0.68; head width across eyes 0.82–0.91 (0.85)/ 0.86–0.91; vertex width 0.43–0.47 (0.43)/ 0.45–0.48; width between ocelli 0.32–0.35 (0.33)/ 0.33–0.37; lengths of antennal segments I–IV respectively 0.20–0.23 (0.20)/ 0.20–0.22, 0.62–0.69 (0.62)/ 0.63–0.68, 0.42–0.45 (0.42)/ 0.42–0.45, and 0.49–0.52 (0.49)/ 0.49–0.53; lengths of labial segments II–IV respectively 0.36–0.44 (0.44)/ 0.38–0.42, 1.06–1.15 (1.10)/ 1.05–1.20, and 0.45–0.49 (0.45)/ 0.46–0.50; anterior pronotal width 0.58–0.64 (0.59)/ 0.62–0.65; mesal pronotal length 0.63–0.70 (0.66)/ 0.65–0.72; basal pronotal width 1.65–1.87 (1.69)/ 1.68–1.90; length of embolial margin 1.50–1.68 (1.55)/ 1.53–1.68; length of cuneal margin 0.83–0.92 (0.85)/ 0.87–0.96; maximum width across hemelytra 1.86–2.06 (1.87)/ 1.86–2.17.

Etymology. Named after Toshihide Ichikawa, the third author, who first discovered this new species and provided the knowledge of its biology.

Type material. HOLOTYPE: 3 ( Figs. 1–3, 5 , 7–9 ), ‘[Shikoku] / Kinbuchi Forest Park / Higashiueta-chô / Takamatsu-shi / Kagawa Pref. / 19–20.vii.2003 / K. Yamada leg.’ ( TKPM). PARATYPES: JAPAN [Shikoku] Kagawa Pref.: Miki-chô, Ikenobe, Yoshidagawa Riv.: 13, 28.iv.2003, T. Ichikawa; 13, 18.viii.2009, T. Ichikawa; 232Ƥ, 21.v.2010, K. Yamada & T. Ichikawa. Takamatsu-shi, Sogouhigashi-machi: 13, 24.vii.2009, T. Ichikawa; 33 (one in Fig. 15 ), 5.viii.2009, T. Ichikawa; 43, 21.v.2010, K. Yamada & T. Ichikawa; 53 (one in Fig. 20 ), 25.v.2011, K. Yamada. Same locality as holotype: 13, 21.viii.2002, T. Ichikawa; 43 (one in Figs. 4 , 6 ), 11.iv.2003, T. Ichikawa; 934Ƥ (one in Fig. 19 ), 25.iv.2003, T. Ichikawa; 231Ƥ, 5.v.2003, M. Takai; 131Ƥ, same date, S. Akagi; 23, same date, E. Doi; 1132Ƥ, same date, T. Yasunaga ( AMNH, TYCN); 63 (one in Fig. 10 ; another in Figs. 11–14 , 16–18 ) 2Ƥ, same data as holotype; 231Ƥ, 18.viii.2003, T. Ichikawa; 43, 28.v.2004, K. Yamada. Takamatsu-shi, Nishiueta-chô: 13, 10.iv.2007, T. Ichikawa. [Kyushu] Kumamoto Pref.: Koushi-shi, Sakae: 33, vii.2003, T. Yasunaga.

Distribution. Japan (Shikoku, Kyushu).

Remarks. This new species is most similar in general appearance to L. zhangi , from which it can be distinguished by the larger body size [3.5–3.9 mm in L. zhangi ], parameres strongly acute at apex [blunt at apex], and acus straight [curved]. Also, whereas L. ichikawai resembles L. variegatus in the shape of the male genitalia, the following external characters of the former are significantly different from the latter: posterior margin of pronotum narrowly pale yellow [broadly pale yellow in L. variegatus ]; clavus blackish brown, with pale yellow markings on basal and median part [almost pale yellow excluding darkened area along claval suture and inner margin]; embolium blackish brown, with pale yellow markings on basal part [mostly pale yellow, with dark brown on median part]; and apex of left paramere not bent inwardly [rather slender and slightly bent inwardly].

Figures

FIGURES 1 – 5. Lyctocoris ichikawai sp. nov., 3. 1, 2, habitus, dorsal and lateral views; 3, head and pronotum, dorsal view; 4, ostiolar peritreme and evaporatorium, left lateroventral view; 5, aedeagus extruding from pygophore, posterior view. 1 – 3, 5, holotype; 4, paratype. Scales: 1.0 mm for 1, 2; 0.5 mm for 3, 4; 0.2 mm for 5.

FIGURES 6 – 9. SEM images of L. ichikawai sp. nov., 3. 6, ostiolar peritreme and evaporatorium, left lateroventral view; 7, aedeagus extruding from pygophore, dorsal view; 8, ditto, posterior view; 9, surface of endosoma. 6, paratype; 7 – 9, holotype. Abbreviations: ac = acus, end = endosoma, lp = left paramere, py = pygophore, rp = right paramere. Scales: 0.2 mm for 6 – 8; 0.05 mm for 9.

FIGURES 10 – 14. Lyctocoris ichikawai sp. nov., 3, paratypes. 10, head and pronotum; 11, right fore wing; 12, right fore leg; 13, right mid leg; 14, right hind leg. Scales: 0.5 mm for 10, 11; 0.2 mm for 12 – 14.

FIGURES 15 – 19. Male (15 – 18) and female (19) genitalia of Lyctocoris ichikawai sp. nov., paratypes. 15, pygophore with parameres (phallobase omitted), dorsal view; 16, left paramere, dorsal view; 17, right paramere, dorsal view; 18, phallobase; 19, genital apophysis, dorsal view. Scales: 0.1 mm.

FIGURE 20 – 22. Live images of Lyctocoris ichikawai sp. nov. 20, habitus, 3, paratype; 21, adult sucking the exuded sap of Quercus acutissima; 22, final instar sucking the exuded sap of Q. acutissima.