Ectamenogonus robustus ( Kishii, 1966 )

Arimoto, Kôichi, 2022, Taxonomic revision of the genus Ectamenognonus Buysson (Coleoptera, Elateridae, Elaterinae) from Japan, Zootaxa 5087 (2), pp. 306-334 : 325-332

Ectamenogonus robustus ( Kishii, 1966)

( Figures 14–18 , 19A–F )

Homotechnes robustus Kishii, 1966: 28 (original description; type locality: Japan, Honshu, Gifu Prefecture, Motosu City , Nukumi Pass).

Ectamenogonus robustus ; Kishii, 1998: 4 (changed generic status).

Ectamenogonus takumii Kishii, 2006: 121 (original description; type locality: Japan, off Kyushu, Nagasaki Prefecture, Tsushima City (Tsushima Island), Mine Town, Mine, Nakazato). Syn. nov.

Type material. Ectamenogonus robustus . Holotype. Male [GN-1435], Japan , Honshu , Gifu Prefecture, Motosu City, Nukumi Pass, 10 VIII 1956, T. Syôji leg. Verbatim label data ( Fig. 17A ). “GN-1435”; “ HOLOTYPE ”; “ NUKUMI PASS / GIFU JAPAN / 10. VIII. ’56. T. SYÔJI ”; “ Homotechnes / robustus/ KISHII, 1966 / DET. T. KISHII, ’66” . Allotype. Female, Japan, Honshu, Kyoto Prefecture, Kyoto City, Shimogyô Ward, Sichijô-Ômiya, 2 IX 1959, Takashi Kishii leg. Paratypes. Japan. Honshu. Niigata Prefecture . 1 female [3069], Shibata City, Akatani Valley , 2 IX 1961, H. Koike leg. ; 1 male [58-118, GN. 2123], Tainai City, Kurokawa , 11 VIII 1958, Kintarô Baba leg. Mie Prefecture. 1 male [ KER01 ], Tanakura (unknown place), 11 VIII 1961, collector unknown. Shiga Prefecture . 1 male [ KER02 ], Takashima City (once Mizuo Village ), 29 VII 1963, J. Kawai leg. Kyoto Prefecture. 1 female [ KER03 ], Kyoto City, Kita Ward, Kamigamo , 20 VII 1963, H. Tamada leg. ; 1 female [ KER04 ], Kyoto City, Sakyô Ward, Matsugasaki , 19 VII 1963, K. Kitagawa leg. ; 1 female [ KER05 ], Kyoto City, Sakyô Ward, Syȗgakuin , 19 IX 1957, T. Syôji leg. ; 1 male [ GN. 364], Kyoto City, Arashiyama , 11 VIII 1953, Takashi Kishii leg. ; 2 females [ KER06 , KER07 ], Kyoto City, Nishikyô Ward, Katsura , 10 VIII 1946, Takashi Kishii leg. ; 1 male [3060], same place, 19 VIII 1965, Shigeru Kazama leg.; 1 female [ KER08 ], Kyoto City, Mt. Kinugasa-yama , 14 VIII 1963, Shirai leg. ; 1 female [ KER09 ], Kyoto City, Nishikyô Ward, Matsuo , 12 VII 1962, H. Asao leg. ; 1 male [ KER10 ], same place, 20 VIII 1959, Ishizawa leg. ; 1 female [ KER11 ], same place, 5 VIII 1965, Shigeo Umeda leg. ; 1 female [3062], Nison-in , 4 VIII 1964, Kôichi Kitagawa leg. ; 1 female [ KER12 ], Kyoto City, Fushimi Ward, Takeda , 2 IX 1961, H. Nomura leg. ; 1 male [ KER13 ], same place, 26 VIII 1964, T. Yagi leg. ; 1 male [ KER14 ], Kyoto City, Fushimi Ward, Momoyama , 29 VIII 1960, Y. Toguchi leg. ; 1 female [ KER15 ], Kyoto City, Sakyô Ward, Mt. Daimonji-yama , 1 VIII 1964, Yoshito Seto leg. ; 1 female [ KER16 ], Kyoto City, Higashiyama Ward , 12 VIII 1963, S. Hirai leg. ; 1 female [ KER17 ], Kyoto City, Yamashina Ward, Mt. Ushio-san , 30 VII 1960, S. Tomimura leg. ; 1 female [ KER18 ], Kyoto City, Kamigyô Ward, Kyoto Gosyo , 28 VIII 1963, D. Mizutani leg. ; 1 male [ KER19 ], Kyoto City, Shimogyô Ward, Sichijô-Karasuma , 19 VII 1960, K. Kane leg. ; 1 female [ KER20 ], Kyoto City, Higashiyama Ward, Maruyama Park , 29 VII 1957, H. Ogura leg. ; 1 female [ KER21 ], Kyoto City, Sakyô Ward, Mt. Hiei-zan , 5 VIII 1956, K. Ôta leg. ; 1 female [ KER22 ], Mukô City, Mukô-machi , 28 VIII 1964, Takane Kinoshita leg. ; 1 female [ KER23 ], Uji City , 11 VIII 1958, K. Dôkuni leg. ; 2 females [ KER24 , KER25 ], Uji City , 29 VIII 1959, T. Horiguchi leg. ; 1 female [ KER26 ], Uji City, Ôbaku , 7 VIII 1965, Sueo Yamada leg. ; 1 female [ KER27 ], Seika Town , 13 VIII 1962, Y. Nishijima leg.

Osaka Prefecture. 1 female [ KER28 ], Hirakata City , 1 VIII 1957, T. Nakamura leg. Hyôgo Prefecture. 1 male [3068], Tazima, Kazumi Town , VIII 1959, T. Takahashi leg.; 1 male [ KER29 ], Inagawa Town , 12 VIII 1963, K. Kumeda leg. Shikoku. 1 female [3064], Tokushima Prefecture, Kuwadaira, 28 VII 1969, T. Shibata leg. Holotype of Ectamenogonus takumii . Male, Japan, off Kyushu, Nagasaki Prefecture, Tsushima City (Tsushima Island), Mine Town, Mine, Nakazato, 11 VIII 2001, Takumi Katô leg. Verbatim label data ( Fig. 19A ). “ HOLOTYPE ”; “8306”; “ ħDz県対馬峰町Ξffi / 中Ψ fi火 / 2001. 8. 11 / leg 加ü 琢Ƌ ”; “ Ectamenogonus / takumii/ Kishii, nov./ Det. T. KISHII, 2003”.

Non-type material. Japan. Honshu. Aomori Prefecture. 1male [G.N. 363], Aomori City, Aburakawa , 29 VI 1944, Takashi Kishii leg. Miyake Island. 1 male [ OER01 ], 9 VII 1964, Tokyo Prefecture, Miyake Village, Tsubota, K. Yamaoka leg. Yamanashi Prefecture. 1 female [ ERF01 ], Nirasaki City, Hosaka Town , 13 VIII 1987, T. Ueno leg. Shizuoka Prefecture. 1 female [ KER32 ], Shizuoka City, Hatanagi Dam , 1100 m, 22 VIII 1992, Koji Hosokawa leg. Ishikawa Prefecture. 1 male [ KER30 ], Hakusan City, Mt. Haku-san, Bettôdeai , 18 VIII 2004, K. Fuji leg. , at light trap. Nagano Prefecture . 1 female [ ERF02 ], Ina City, Todai , 1 VIII 1988, Hisayuki Arimoto leg. ; 1 female [ ERF03 ], Kiso District, Nagiso Town, Azuma , Urushihata , Minamiararagi National Forest , 16 VIII 2012, Ryôji Toyoshima leg. Gifu Prefecture. 1 male, 1 female [ ERM01 , ERF04 ], Takayama City, Syokawa Town (once Ôno District , Syokawa Village ), Ogamigô , 13 VIII 1995, Nobuhisa Yuzawa leg. ; 1 male [ ERM02 ], same place as the former, 12 VIII 1995, Nobuhisa Yuzawa leg. ; 1 female [ ERF05 ], Ôno District, Shirakawa Village, near Ôshira-kawa River , 15 VIII 1994, N. Yuzawa leg. Shiga Prefecture. 1 male [ ERM03 ], Nagahama City (once Yogo Town ), 28 VII 1989, Hisayuki Arimoto leg. ; 1 female [ MRF06 ], near Lake Biwa , 15 VIII 1974, T. Tanaka leg. ; 1 female [ ERF07 ], Higashiômi City (once Kanzaki District, Eigenji Town ), Kiwada Town , 13 VIII 1999, Hisayuki Arimoto leg. Kyoto Prefecture. 1 female [ KER33 ], Kyoto City, Sakyô Ward, Syôgo-in , 12 VIII 1960, K. Adachi leg. Nara Prefecture. 1 male, 3 females [ ERM04 , ERF08–10 ], Yoshino District, Kamikitayama Village, Shintyaya-dani Valley , 800–1000 m, 14 VIII 2009, Hiroshi Nozaki leg. ; 1 female [ ERF11 ], same place as the former, 800 m, 29 VII 2006, Hisayuki Arimoto leg. ; 1 female [ MRF12 ], Nara City, Nara Park , 15 VIII 2012, Tateo Itô leg. Shimane Prefecture. 1 female [3066], Unnan City, Daitô Town , 4 V 1968, H. Kadowaki leg. Yamaguchi Prefecture. 1 female [ KER31 ], Hagi City (once Abu District, Fukuei Village ), 11 IX 1998, Hiroaki Mukunoki leg. Oki Islands. 1 male [3065], Oki District, Okinoshima Town, Saigô , Ariki , 6 VIII 1966, H. Kadowaki leg. Kyushu. Ôita Prefecture. 2 males [ ERM05 , ERM08 ], Kusu District, Kokonoe Town, Mt. Kuenhira-yama , 15 VIII 1998, Seiya Ogata leg. , by light traps; 1 male [ ERM06 ], same place as the former, 23 VIII 2003, Seiya Ogata leg. , by light traps; 1 male [ ERM07 ], same place as the former, 6 VIII 2005, Seiya Ogata leg. , by light traps. 1 male [ ERM09 ], same place as the former, 17 VIII 2000, Seiya Ogata leg. , by light traps; 1 female [ ERF13 ], same place as the former, 18 VII 2004, Seiya Ogata leg. , by light traps. Tsushima Island. 2 females [ ERF14 , ERF15 ], Nagasaki Prefecture, Tsushima City, Izuhara Town, Tsutsu , 7–8 VIII 2009, Kôichi Arimoto leg.

Diagnosis. Antennae just or not reaching pronotum posterior lateral apices by apical antennomere in male. Antennomere IV 0.9–1.1 x longer than II–III combined. Prothorax 1.0–1.1 x longer than wide. Posterior edge of scutellar shield rounded but truncate in some. Elytra 2.4–2.6 x longer than wide, 2.1–2.6 x longer than pronotum length. Aedeagus 3.3 x longer than wide. Median lobe exceeding apices of parameres by apical 1/5 to 1/4. Paramere apex length 1.3–1.8 x width of parameres at expansions. Spiculum ventrale 3.6–3.8 x longer than sternite VIII. Ovipositor 1.2–1.3 x longer than length of midline of abdominal ventrites. Bursa copulatrix 1.0–1.1 x length of uterus, with a cluster of sclerotized spines.

Measurements. Holotype of E. robustus . BL: 11.8, BW: 3.23, MAE: 1.88, MBE: 1.11; OI: 168, PL: 3.29, PML: 2.79, PW: 3.18, PI: 103, EL: 8.17, EW: 3.23, EI: 253, BI: 249. Holotype of E. takumii . BL: 12.1, BW: 3.49, MAE: 2.02, MBE: 1.19; OI: 170, PL: 3.72, PML: 3.13, PW: 3.49, PI: 107, EL: 8.08, EW: 3.37, EI: 239, BI: 217. Male (21 specimens). BL: 10.9–13.3, BW: 3.04–3.64, MAE: 1.79–2.16, MBE: 1.05–1.35; OI: 159–171, PL: 3.24–3.99, PML: 2.71–3.33, PW: 3.01–3.64, PI: 101–110, EL: 7.27–8.71, EW: 3.04–3.60, EI: 236–255, BI: 214–243. Female (42 specimens). BL: 11.7–16.2, BW: 3.22–4.63, MAE: 1.92–2.53, MBE: 1.16–1.60; OI: 152–170, PL: 3.19–4.88, PML: 2.69–4.06, PW: 3.17–4.63, PI: 101–111, EL: 8.03–10.98, EW: 3.22–4.57, EI: 235–253, BI: 214–255.

Redescription. Body widest near pronotum hind angles or posterior half of elytra; surface with microstructures; interspaces between punctures generally larger than puncture diameter but partly smaller than puncture diameter. Color. Body black-brown to red-brown ( Figs. 1F, 1G , 2A, 2B ). Labrum reddish ( Figs. 14C , 15C ).Antennae red-brown to orange ( Figs. 1F, 1G , 2A, 2B ). Mandible reddish but apical parts black ( Figs. 14C , 15C ). Maxillary palpomeres orange ( Figs. 14C , 15C ). Posterior edge of pronotum, anterior lobe of prosternum and mesial margin and posterior part of hypomeron reddish ( Figs. 1F, 1G , 2A, 2B , 14C, 14H , 15C, 15H ). Elytra around striae blackish, reddish in posterior margin ( Fig. 1F, 1G , 2A, 2B ). Legs red-brown to orange but partly blackish ( Figs. 14A , 15A ). Posterior margin of abdominal ventrite V orange ( Figs. 14A , 15A ). Male. Tergites and sternites VIII‒X and aedeagus yellow to yellow-brown but partly black-brown ( Figs. 16 , 17C–F ). Female. Tergites and sternites VIII red-brown ( Fig. 18A, B . Body covered with yellow-brown to red-brown setae.

Head. Frons beyond eyes in anterior view 0.3 x longer than wide ( Figs. 14B , 15B ); supra-antennal carina in ventral view weakly emarginte medially ( Fig. 14C ). Male. Antennae just or not reaching pronotum posterior lateral apices by apical antennomere, extending beyond pronotum posterior margin excluding posterior angles by apical antennomere ( Fig. 1G ); antennomere II 1.0–1.2 x longer than wide; III 1.6–2.0 x longer than wide; IV 1.8–2.1 x longer than wide, 1.0–1.1 x longer than II–III combined ( Figs. 14D , 15D ), 1.0–1.1 x longer than V; V 1.7–2.0 x longer than wide; XI 2.4–2.6 x longer than wide ( Figs.14E , 15E ). Female. Antennae not reaching pronotum posterior margin excluding posterior angles by apical antennomere ( Fig. 1H ); antennomere II 0.9–1.4 x longer than wide; III 1.5–2.1 x longer than wide; IV 1.8–2.0 x longer than wide, 0.9–1.1 x longer than II–III combined, 1.0–1.2 x longer than V; V 1.5–1.9 x longer than wide; XI 2.0–2.4 x longer than wide.

Prothorax 1.0–1.1 x longer than wide, widening posteriad, widest behind hind angles but at posterior lateral apices in some; sides rounded in anterior 1/3, straight in posterior 2/3. Pronotum without median longitudinal depression. Prosternum: ventral margin weakly inclined in anterior 1/5 (at 13–19 degrees against prosternal horizontal line, Figs. 14F , 15F ); anterior lobe exceeding anterior angles of prothorax ( Figs. 14F , 15F ). Prosternal process depressed between procoxae ( Figs. 14H , 15H ), in profile strongly inclined and then almost horizontal behind procoxae ( Figs. 14F , 15F ); sides of dorsal lobe broadly rounded, widest anteriorly; ventral margin of ventral lobe in profile straight anteriorly and rounded posteriorly; apex in ventral and lateral views rounded ( Figs. 14A , 15A ). Hypomeron slightly grooved next to impunctate ridge ( Fig. 14H : white arrow). Pronotosternal sutures moderately opened anteriorly ( Figs. 14H , 15H ). Scutellar shield 1.4–1.5 x longer than wide, widest anteriorly or near anterior half, broadly convex, strongly inclined anterior-downwards, not visible in profile ( Figs. 14F , 15F ); anterior edge straight but slightly rounded in some; sides broadly rounded anteriorly; posterior edge rounded but truncate in some. Mesosternum: posterior edge 0.1 x wider than mesosternum width, triangularly emarginate ( Figs. 14I , 15I : arrow), with widely rounded angles, borders of mesosternal cavity in profile horizontal anteriorly and then roundly and gradually inclined ( Figs. 14F , 15F ). Elytra 2.4–2.6 x longer than wide, 2.1–2.6 x longer than pronotum length; apex emarginate; apical outer edge of each elytron rounded; apical internal edge of each elytron slightly pointed or rounded (likely due to damage) ( Figs. 14J , 15J ).

Abdomen. Ventrite V 0.6–0.7 x longer than wide ( Figs. 14A , 15A ). Male. Tergite VIII 1.1–1.2 x longer than wide, rounded apically ( Fig. 16A ) but emarginate in a few. Sternite VIII with posterior edge almost straight ( Fig. 16B ). Tergite IX 1.1–1.3 x length of tergite X, with median notch rounded ( Fig. 16C ). Tergite X 1.0–1.1 x longer than wide, rounded apically ( Fig. 16C ). Sternite IX 2.5–2.9 x longer than wide, rounded apically ( Fig. 16D ). Aedeagus 3.3 x longer than wide ( Figs. 16E, 16F , 17E ). Phallobase 0.5 x total length of aedeagus, 1.5–1.7 x longer than wide. Median lobe exceeding apices of parameres by apical 1/5 to 1/4; basal struts 0.4 x total length of median lobe. Parameres fused ventrally; preapical expansions not projecting, slightly projecting laterally ( Figs. 16G , 17F ) or distinctly projecting laterally beyond side of apex ( Fig. 19F ); apex beyond preapical expansions blade-like shaped ( Figs. 16G , 17F ), rounded laterally, with two to four setae and zero to one sensilla dorsally, with one to four setae and three to ten sensilla ventrally; apex length 1.3–1.8 x width of parameres at expansions in ventral side. Female. Tergite VIII 1.4–1.5 x longer than wide ( Fig. 18C ). Sternite VIII 1.2–1.3 x longer than wide ( Fig. 18D ); spiculum ventrale 3.6–4.0 x length of sternite VIII ( Fig. 18A, B ). Ovipositor 1.2–1.3 x longer than length of midline of abdominal ventrites; coxites two segmented at ventral side ( Fig. 18H ), with some setae; stylus with setae around apex ( Fig. 18H ). Vagina long; uterus globular ( Fig. 18A, B ); bursa copulatrix U-shaped, short, 1.0–1.1 x length of uterus ( Fig. 18A, B ), with 35–55 sclerotized spines forming a row ( Fig. 18E ); long thin sac extending from apex of bursa copulatrix ( Fig. 18F ), with thin coiled sac near apex of bursa copulatrix ( Fig. 18F, G ).

Comparative notes. Ectamenogonus robustus is distinguished from the Japanese congeners by the following contrasting characters (the other species in parentheses): antennomere IV 0.9–1.1 x longer than II–III combined (antennomere IV 1.1–1.5 x longer than II–III combined); prothorax 1.0–1.1 x longer than wide, PI: 101–111 (prothorax 1.1–1.2 x longer than wide, PI: 113–123); aedeagus 3.3 x longer than wide (aedeagus 3.6–4.3 x longer than wide); median lobe exceeding apices of parameres by apical 1/5 to 1/4 (median lobe exceeding apices of parameres by apical 1/4 to 1/3); paramere apex length 1.3–1.8 x width of parameres at expansions (paramere apex length 1.9–2.2 x width of parameres at expansions); bursa copulatrix 1.0–1.1 x length of uterus (bursa copulatrix 1.7–2.7 x length of uterus); bursa copulatrix with a cluster of sclerotized spines (bursa copulatrix with two clusters of sclerotized spines).

Discussion. E. takumii should be a junior synonym of E. robustus . The status of E. takumii is discussed in detail under E. plebejus .

Yaku Island was included in the range of E. robustus without specimen information ( Kishii, 1987). Subsequently, Kishii (1999) excluded the island from its range. This study examined a specimen from the island to which Kishii attached the identification label E. robustus (KEP32) in OMNH and found that the specimen belongs to E. plebejus based on features of the antennomere and bursa copulatrix. Hence, E. robustus was removed from Yaku Island following the treatment of Kishii (1999).

Distribution ( Fig. 20A ). Japan: Hokkaido, Honshu, Miyake Island (off Honshu), Oki Islands (off Honshu), Shikoku, Kyushu, Tsushima Island (off Kyushu) ( Kishii, 1999; this study).

Ecology. This species is often collected by light traps at night ( Ôhira, 1999; Arimoto, 2017) and sometimes found in hollows of trees ( Ozaki et al., 2006).

Figures

FIGURE 1. Ectamenogonus spp., habitus, dorsal view. A: E. matobai, holotype, female; B: E. miyakoensis, holotype, male [EMM01]; C: E. miyakoensis, paratype, female [EMF01]; D; E. plebejus, male [EPM01]; E: E. plebejus, female [EPF02]; F: E. robustus, male [ERM01]; G: E. robustus [ERF11].

FIGURE 2. Ectamenogonus spp., habitus, dorsal view. A: H: E. robustus, holotype, male; B: E. takumii, male, holotype (= E. robustus); C: E. takumii, female, paratype (= E. plebejus); D: E. yakuensis, holotype, male (= E. plebejus); E: labels for holotype of E. yakuensis.

FIGURE 14. Ectamenogonus robustus (Kishii, 1966), male. A: [ERM07]; B–F, J: [ERM01]; G: [KER14]; H, I: [ERM06]. A: habitus, ventral view; B: head, anterior view; C: head, ventral view; D: basal parts of right antenna and head, laterodorsal view; E: apical parts of right antenna; F: head, prothorax and mesothorax, lateral view; G: scutellum; H: mesothorax and metasternum, lateroventral view (white arrow: hypomeron slightly grooved next to impunctate ridge); I: border between mesosternum and metasternum, ventral view (arrow: posterior edge of mesosternum triangularly emarginate); J: posterior edges of elytra.

FIGURE 15. Ectamenogonus takumii Kishii, 2006, holotype, male. A: habitus, ventral view; B: head, anterior view; C: head, ventral view; D: basal parts of right antenna and head, laterodorsal view; E: apical parts of right antenna; F: head, prothorax and mesothorax, lateral view; G: scutellum; H: mesothorax and metasternum, lateroventral view; I: border between mesosternum and metasternum, ventral view (arrow: posterior edge of mesosternum triangularly emarginate); J: posterior edges of elytra.

FIGURE 16. Ectamenogonus robustus (Kishii, 1966), male [EPM03]. A: tergite VIII; B: sternite VIII; C: tergites IX–X; D: sternite IX; E: aedeagus, dorsal view; F: aedeagus, ventral view; G: apical part of lateral lobe of aedeagus, dorsal view.

FIGURE 17. Ectamenogonus robustus (Kishii, 1966), holotype, male. A: labels; B: slide; C: tergite VIII; D: sternite IX; E: aedeagus, dorsal view; F: apical part of lateral lobe of aedeagus, dorsal view.

FIGURE 18. Ectamenogonus robustus (Kishii, 1966), female. A, C–G: [ERF09]; B: [ERF15], H: [ERF01]. A: genitalia; B: genitalia; C: tergite VIII, dorsal view; D: sternite VIII and tergite VIII, ventral view; E: sclerotized spines cluster in bursa copulatrix; F, G: long thin sac extending from apex of bursa copulatrix; H: apical part of ovipositor, ventral view.

FIGURE 19. A–E: E. takumii Kishii, 2006, holotype, male (= E. robustus); G–K: E. takumii Kishii, 2006, paratype, female (= E. plebejus). A, G: labels; B, H: slide; C: tergite VIII; D: sternite IX; E: aedeagus, dorsal view; F: apical part of lateral lobe of aedeagus, dorsal view; I: genitalia; J: sclerotized spines cluster in first half of bursa copulatrix; K: sclerotized spines rows in latter half of bursa copulatrix.

FIGURE 20. Map of the study area showing the location of the islands mentioned in this study. A: East Asia; B: Ryukyu Islands.