Malthodes morimotoi Imasaka & N. Takahashi, 2020

Takahashi, Naoki & Imasaka, Shôichi, 2020, Two new species and a new distribution record of the genus Malthodes Kiesenwetter (Coleoptera: Cantharidae) from Japan, with notes on the male and female abdominal morphology, Zootaxa 4778 (2), pp. 357-371 : 358-363

Malthodes morimotoi Imasaka & N. Takahashi , sp. nov.

( Figs. 1–3 , 10–18 , 33 )

Malthodes kurosawai (subsp.?): Nakane, 1959: 17. (misidentification).

Malthodes kurosawai: Takakura, 1977: 9 , pl. 1, figs. 28–33, 35. (misidentification).

Malthodes hikosanus: Imasaka, 1989: 16 , figs. 1–4; Imasaka & Abiru, 1989: 14. (misidentification).

Malthodes sp. 1: Imasaka et al., 1987: 187; Imasaka & Ohtsuka, 1996: 60, 69; Imasaka, 2000: 27; Imasaka & Nishida, 2002: 423; Nishida, 2005: 18; Imasaka & Miyake, 2011: 43; Fukagawa et al., 2016: 61; Imasaka et al., 2018: 35.

Type materials. Holotype (deposited in ELKU collection), male, Japan, Kyushu, Fukuoka Pref., Mt. Tachibana , 29.iv.1994, N. Takahashi leg.

214 Paratypes (93 males and 121 females): HONSHU (Yamaguchi Pref.) Shimonoseki City, Tôgyô-an , 27.iv.1996, SI (1 male, SIC) . Shimonoseki City, Gesan , 30.v.2006, Y. Okushima leg. (1 female, KURA) . Shimonoseki City, Chôfu, Kôzanji Temple , 27.iv.1996, SI (1 male, SIC) . KYUSHU (Fukuoka Pref.) Yamada City, Kumagahata , 3.v.1978, Y. Takakura leg. (1 female, KMNH) . Shikanoshima Is. , 26.iv.1994, H. Kojima leg. (1 female, NTC) . Mt. Tachibana , 14.iv.1979, K. Morimoto leg. (1 male, ELKU) ; 30.iv.1979, K. Morimoto leg. (1 female, ELKU; 1 female, NTC) ; 17.iv.1994, K. Yoshizawa leg. (7 males and 1 female, NTC) ; 25.iv.1994, NT (3 females, NTC) ; 29.iv.1994, NT (4 males and 1 female, NTC) ; 7.v.1994, NT (1 male, NTC) . Mt. Inunaki , 11.v.1935, K. Yasumatsu leg. (1 female, ELKU) ; 5.v.1997, R. Matsumoto leg. (1 female, NTC) . Hisayama-machi , 24.iv.1994, N. Wasano leg. (1 male and 1 female, NTC) . Mt. Sangun , 10.v.1931, K. Yasumatsu leg. (1 female, ELKU) . Mt. Sangun, Akaneya , 20.iv.1997, SI (2 males and 1 female, SIC) . Mt. Hôman , 6.iv.1931, Hori, Fujino & Chô leg. (1 male, ELKU) . Soeda Town, Ôyabu , 19.iv.1987, Y. Takakura leg. (1 male, KMNH) . Mt. Hiko , 8–10.v.1957, K. Morimoto leg. (1 male, ELKU) ; 9.v.1957, K. Morimoto leg. (3 females, ELKU) ; 1.v.1958, Y. Miyatake leg. (2 males and 1 female, ELKU; 1 male and 1 female, NTC) ; 3.v.1969, by Malaise trap, K. Takeno leg. (1 female, ELKU) ; 2.v.1971, H. Makihara leg. (1 male, ELKU) ; 13.v.1971, by Malaise trap, K. Takeno leg. (1 female, ELKU) ; 5.v.1978, Y. Takakura leg. (1 female, KMNH) ; 16.v.1978, K. Morimoto leg. (1 male and 3 females, ELKU; 3 females, NTC) ; 3.v.1992, T. Ueno leg. (2 males, KURA) ; 4.v.1994, T. Yamauchi leg. (2 males, NTC) ; 5.v.1994, T. Yamauchi leg. (1 male and 2 females, NTC) ; 25.v.1994, NT (1 male, NTC) ; 7.v.1995, Y. Aoki leg. (1 male, SIC) ; 24.v.1996, Y. Higashiura leg. (1 female, NTC) ; 2.v.2012, NT (1 male and 2 females, NTC) . Mts. Hiko , Nr. Notouge (alt. 800 m), 26.iv.2001, H. Inoue leg. (2 males, NTC) . Miyako-machi, Kyouyomi-rindô—Notouge [Pass], 10.v.2012, NT (2 males, NTC) ; 4.vi.2012, NT (1 female, NTC) . Mt. Inugatake , 27.iv.1999, H. Inoue leg. (1 male, NTC) ; 20.v.1999, H. Inoue leg. (1 male and 1 female, NTC) . Mt. Abura , 17.iv.1994, Y. Higashiura leg. (2 females, NTC) . Nokonoshima Is. , 14.iv.1998, H. Fujimoto leg. (1 male, NTC) . Nishi Ward, Atago Shrine , 4.v.2001, H. Fujimoto leg. (1 female, NTC) . Mt. Rai-zan , 28.v.1995, R. Matsumoto leg. (1 female, NTC) . Mt. Sefuri , 9.v.1994, NT (1 female, NTC) ; 16.v.1995, H. Goto leg. (1 male, NTC) ; 1.v.1997, R. Matsumoto leg. (1 male, NTC) ; 12.v.2000, S. Sato leg. (2 males and 1 female, NTC). (Saga Pref.) Mt. Ishitani , 16.v.2000, SI (2 males and 4 females, SIC) . Mt. Asahi , 20.iv.1997, SI (8 males and 15 females, SIC) . Mt. Sefuri , 13.v.1995, SI (1 male, SIC) ; 22.v.2000, SI (3 males and 7 females, SIC) ; 5.v.2002 (alt. 1,000 m), H. Inoue leg. (1 female, NTC) ; 13.v.2002 (alt. 1,000 m), H. Inoue leg. (1 male, NTC) . Mitsuse Vil., Ideno—Shiibaru [Shiiba] Pass , 21.v.1994, NT (1 male and 4 females, NTC) . Mitsuse Vil., Ideno , 13.v.1995, SI (1 males and 12 females, SIC) . Mt. Tara (alt. 550–700 m), 20.v.2001, T. Yamauchi leg. (3 females, NTC) . Mt. Tara, Nakayama , 5.v.1986, M. Nisida leg. (1 male, SIC) . Mt. Tara, Tara-Nakayama, 28.iv.2001, by light trap, T. Yam- auchi leg. (2 males and 1 female, NTC). (Nagasaki Pref.) Shimabara City, Mt. Mayumaya , 9.iv.1976, SI (1 male, SIC) ; 19.iv.1978, SI (1 male, SIC) . Shimabara City, Mt. Yakeyama , 16.iv.1977, SI (1 male, SIC) ; 9.v.1978, SI (3 females, SIC) . Shimabara City, Kueyama , 5.iv.1976, SI (1 male, SIC) ; 1.iv.1977, SI (2 males, SIC) ; 6.iv.1986, SI (1 male, SIC) ; 1.iv.1997, SI (2 males and 1 female, SIC) . Shimabara City, Kamikoba , 21.iv.1976, SI (1 male, SIC) ; 29.iv.1985, SI (2 females, SIC) . Shimabara City, Motoike , 5.iv.1987, SI (1male, SIC) . Mt. Azuma , 10.iv.1979, SI (1 male, SIC) . Kunimi Town, Kôjiro , 20.iv.1988, SI (1 male, SIC) . Shimabara City, Senbuki , 22.iv.1979, SI (1 male, SIC) ; 20.v.1986, SI (1 female, SIC) ; 7.v.1987, SI (2 females, SIC) . Mt. Tara , Shû-tara-no-mori, 2.v.1995, SI (1 male and 1 female, SIC) . Mt. Tara, Minamikawachi-rindô , 10.v.1986, SI (2 females, SIC) . Mt. Tara, Hiratani , 28.iv.1981, SI (1 female, SIC) . Mt. Tara, Todoroki Fall , 8.v.1977, SI (1 female, SIC) ; 28.iv.1984, SI (1 male, SIC) ; 19.iv.1989, SI (1 male and 1 female, SIC) ; 6.v.1989, SI (1 male and 1 female, SIC) . Mt. Tara, Koe-rindô , 6.v.1995, Y. Aoki leg. (1 male, SIC) . Mt. Unzen , 28.v.1987, SI (1 male and 2 females, SIC) . Kazusa Town, Gonda Park , 20.iv.1993, SI (1 female, SIC). (Ôita Pref.) Chôjabaru—Bôgatsuru , 22.v.1994, H. Kojima leg. (1 female, NTC). (Kumamoto Pref.) Senomoto-kôgen , 12.v.1996, SI (2 males and 1 female, SIC) . Minamioguni-machi, Senomoto , 15.v.1998, R. Matsumoto leg. (1 female, NTC) . Kikuchi City, Kikuchi Vall. , 29.iv.1997, SI (3 females, SIC) . Yabe Town, Komagaeri Pass , 26.v.1997, SI (1 male, SIC) ; 27.v.1997, SI (2 females, SIC) . Yabe-machi, Shiiya Pass , 29.v.1999, SI (3 females, SIC) . Izumi Vil., Gokanoshô, Hagi , 25.iv.1989, SI (1 male, SIC) ; 19.v.1996, SI (3 males and 1 female, SIC) . Mt. Shiraga , 4.vi.1984, M. Ôhara leg. (1 male and 1 female, SIC) .

Additional materials examined. KYUSHU (Fukuoka Pref.) Tagawa City, 17.iv.1974, Y.Takakura leg. (2 males, KMNH). (Kagoshima Pref.) Mt. Hoyoshi , 20.iv–20.v.2000, by Malaise trap, T. Muroi leg. (1 female, NTC) .

Diagnosis. Body ( Figs. 1–2 ) relatively large, dark brown to black. Male: abdominal tergite X developed, dilated apically at sides, triangularly swollen dorsally in basal part in dorsal view ( Fig. 12 ), doubly bent ventrally in profile ( Figs. 10 , 33 ); abdominal sternite IX well sclerotized, elongate with a Y-shaped apex in ventral view ( Fig. 11 ), gently arcuate ventrally in profile ( Figs. 10 , 33 ). Aedeagus ( Figs. 22–24 ): basophysis relatively flattened and curved medio-dorsally in apical part in dorsal view; tergal lobe of tegmen remarkably produced apically beyond apical margin of sternal lobe of tegmen in profile. Female: abdominal tergite VIII ( Figs. 16 , 33 ) semicircularly elevated in basal half though depressed around emargination at basal margin. Ovipositor ( Fig. 18 ): coxite rounded though faintly truncate and somewhat narrowed medio-apically at apical margin, and feebly warped dorsally in apical portion.

This new species is similar to M. kurosawai Wittmer, 1954 in general appearance and with a Y-shaped abdominal sternite IX, but can be easily distinguished by the developed abdominal tergite X, the produced apical margin of tergal lobe of tegmen and the curved basophyses of tegmen in the aedeagus.

Description. MALE ( Fig. 1 ). Head black but somewhat brownish around clypeus; eyes dark brownish black to black; mandibles and pretarsal claws reddish brown though sometimes yellowish in basal parts; maxillary and labial palpi, antennae, pronotum, scutellum, elytra, ventral side of thorax, legs, most of abdomen dark brown, though somewhat reddish on prosternum, mesoventrite, mesanepisterna, mesepimera, metaventrite and metanepisterna, sometimes so on most of abdomen, often more brownish on legs with yellowish trochanters and basal parts of tibiae; mouth parts except the aforementioned parts, abdominal tergites IX and X and sternite IX yellowish orange though often partly brownish on tergites IX and X.

Body elongate, densely covered with dark brownish and recumbent pubescence, but covered with slightly lighter pubescence on abdominal tergites IX and X and sternite IX, fitted with longish pubescence around clypeus; antennae, tibiae, tarsi, abdominal sternite IX, and tergite X covered with suberect bristles.

Head wider than long, 1.08 (in the holotype; range 1.06–1.17) times wider than pronotum; surface relatively lustrous; mandibles finely serrulate on incisor edges; eyes large, interocular distance 1.57 (1.56–1.93) times larger than radius of eye; antennae filiform and relatively long, slightly extending over elytral apices, relative lengths of antennomeres from base as follows:— 14.6: 10.0: 10.8: 14.8: 15.5: 15.4: 14.5: 14.1: 13.5: 12.6: 14.6.

Pronotum subrectangular, 1.49 (1.36–1.50) times wider than long; disc feebly convex medio-dorsally, with a lenticular depression in medio-longitudinal area and reniform depressions along lateral margins, relatively lustrous though somewhat matt on lateral depressed areas and hypomera, subtruncate but arcuate on both sides at anterior margin, obliquely truncate and slightly warped dorsally at front angles, gently arcuate posteriorly at posterior margin, weakly produced laterally at hind angles, shallowly emarginate medially and slightly dilated posteriorly at sides.

Elytra 2.78 (2.53–2.99) times longer than wide; surface feebly rugulose but relatively smooth in basal areas and apical portions, weakly marginate along sutural line, with a few rather undefined costae on each elytron.

Prosternum, meso- and metaventrites, mesanepisterna, mesepimera, and metanepisterna lustrous on their surfaces, though slightly matt on anterior parts of metanepisterna and often so on mesanepisterna and mesepimera.

Most of abdominal sternites lustrous and faintly rugulose on surface; abdominal tergite X ( Fig. 12 ) dilated apically at sides, convex medio-dorsally though gently so on apical part, triangularly swollen dorsally in basal part, and matt on basal area including swollen part in dorsal view, slightly arcuate dorsally in basal part and depressed apically behind triangularly swollen part with a short medio-longitudinal carina in profile; sternite IX ( Fig. 11 ) well sclerotized, elongate with a Y-shaped apex, gradually narrowed apically before Y-shaped apical portion in ventral view, gently arcuate ventrally, convex medio-ventrally with a medio-longitudinal depression in basal half, and feebly convex in apical portion in profile.

Aedeagus ( Figs. 13–15 ) somewhat stout, nearly elliptical in outline in dorsal view: sternal lobe of tegmen subquadrate, shallowly emarginate at apical margin, and strongly constricted just behind rotundate apical angles at sides in ventral view, weakly convex medio-ventrally though more clearly so in basal part, warped dorsally in lateral areas, and arcuate dorsally at lateral margins behind constrictions in profile; tergal platelet of median lobe stout U-shaped and tapered laterally at apices in dorsal view; tergal lobe of tegmen nearly elliptical in outline, but somewhat flattened at apical margin, weakly constricted at sides around the bases of basophyses, rotundate at base, gently concave medio-ventrally on dorsal surface though swollen dorsally in basal part, and covered with longish setae in apical part in dorsal view, remarkably produced apically beyond apical margin of sternal lobe in profile; basophysis of tegmen relatively flattened and curved medio-dorsally in apical part in dorsal view, rounded at angles and slightly emarginate in the middle at apical margin in profile; penis slender, tapered apically, and subtly warped dorsally in apical portion in profile.

Body length: 4.0 (3.4–4.1) mm; width: 1.0 (0.9–1.0) mm.

FEMALE ( Fig. 2 ). Almost similar to male, but body sometimes slightly stouter and darker in coloration than in male; apical abdominal segments almost dark brown. Head slightly narrower than in male; eyes smaller than in male, interocular distance 2.71–2.98 times larger than radius of eye; antennae shorter, reaching a little more than basal half of elytra, relative lengths of antennomeres from base as follows:— 16.1: 10.0: 10.4: 12.8: 13.4: 12.5: 12.2: 11.3: 11.1: 10.2: 13.0. Pronotum ( Fig. 3 ) somewhat wider in appearance, 1.36–1.47 times wider than long, and 1.05–1.13 times wider than head; disc less emarginate medially at sides and evener than in male. Elytra 2.37–2.97 times as long as wide.

Abdominal tergite VII subrectangular, dilated apically in dorsal view, marginate along basal margin on ventral (= inner) surface (arrowed in Fig. 16 ); copulatory depression (sensu Takahashi 2001) recognized on tergite VIII; tergite VIII relatively large, somewhat trapezoidal in outline, generally convex medio-dorsally, feebly sinuate and narrowed apically at sides, gently arcuate apically but slightly emarginate basally in the middle at apical margin, roundly emarginate in the middle at basal margin, marginate along basal margin on ventral (= inner) surface (arrowed in Fig. 16 ), semicircularly elevated in basal half though depressed around the emargination at basal margin.

Ovipositor ( Fig. 18 ): coxite rounded though faintly truncate and somewhat narrowed medio-apically at apical margin, and feebly warped dorsally in apical portion, concave in basal portion, with a lapel at medio-basal margin in ventral view; paraproct semicylindrical though slightly flattened dorso-ventrally, weakly dilated basally, shallowly emarginate at apico-dorsal margin in dorsal view, conically protruded with round tips at apical angles, and reaching around apices of coxites in ventral view.

Body length: 3.2–3.9 mm; width: 0.9–1.1 mm.

Distribution. Japan: westernmost part of Honshu and Kyushu.

Infraspecific variation. Female abdominal sternite VIII is gradually narrowed posteriorly in the ventral view and more narrowed in the posterior area where the sides are sometimes shallowly emarginated medially; tergite VIII is gently bisinuated at the posterior margin in the dorsal view, but sometimes subtruncated on both sides and feebly notched in the middle, or slightly arcuated on both sides and emarginated in the middle; apical part of the coxite is subtly elongate in some cases.

Etymology. This specific epithet is given in honor of the late Dr. Katsura Morimoto (deceased on 3 September 2019) who was an eminent researcher on weevils and our supervisor at the Kyushu University, as well as a collector of materials examined here. We propose that the Japanese name of this new species is “Morimoto-kurochibijôkai”.

Figures

FIGURE 33. Schema of morphological correspondence in Malthodes morimotoi Imasaka & N. Takahashi, sp. nov. between male (in lateral view; right) and female (in dorsal view; left) apical portions of abdomina in copulation. A, correspondence between basal part of male tergite X and copulatory depression on female tergite VIII; B, correspondence between apical margin of male tergite X and basal margin of female tergite VII. Abbreviations: st IX, sternite IX; tg VII, tergite VII; tg VIII, tergite VIII; tg IX, tergite IX; tg X, tergite X.

FIGURES 1–9. Habitus of Malthodes spp. 1–3, Malthodes morimotoi Imasaka & N. Takahashi, sp. nov.; 4–6, M. parvus Kazantsev; 7–9, M. okushimai Imasaka & N. Takahashi, sp. nov.; 1, 4, 7, males; 2, 5, 8, females; 3, 6, 9, female pronota. Scales: 1.0 mm (Figs 1–2, 4–5, 7–8); 0.2 mm (Figs 3, 6 and 9).

FIGURES 10–15. Malthodes morimotoi Imasaka & N. Takahashi, sp. nov., male. 10, apical portion of abdomen, lateral view; 11, abdominal sternite IX, ventral view; 12, abdominal tergite X, dorso-caudal view; 13–15, aedeagus (13, dorsal view; 14, lateral view; 15, ventral view). The arrows in the upper (for Fig. 10) and right margins (for Figs 11–15) explain the meaning of the terms “basal” and “apical”, as used in description: they correspond to the “anterior” and “posterior”, respectively.Abbreviations: bp, basophysis; pe, penis; sl, sternal lobe; tl, tergal lobe; tp, tergal platelet. Scales: 0.2 mm (Figs 10–12); 0.1 mm (Figs 13–15).

FIGURES 16–18. Malthodes morimotoi Imasaka & N. Takahashi, sp. nov., female. 16–17, abdomial segments VII and VIII (16, dorsal view; 17, lateral view); 18, ovipositor, ventral view. The large arrow representations are the same as those in Figs 10–15 (one in the upper margin for Fig. 17; the other one in the right margin for Figs 16 and 18). The small arrows in Fig. 16 point zigzag lines showing the positions of marginated basal margin on ventral (= innner) surface of tergites VII and VIII. Abbreviations: c, coxite; cd, copulatory depression; lc, lapel of coxite; pp, paraproct. Scales: 0.2 mm.

FIGURES 19–24. Malthodes okushimai Imasaka & N. Takahashi, sp. nov., male. 19, apical portion of abdomen, lateral view; 20, abdominal sternite IX, ventral view; 21, abdominal tergite X, dorsal view; 22–24, aedeagus (22, dorsal view; 23, lateral view; 24, ventral view). The arrow representations are the same as those in Figs 10–15 (one in the upper margin for Fig. 19; the other one in the right margin for Figs 20–24). Abbreviation: plb, processus laminae basalis. Scales: 0.2 mm (Figs 19–21); 0.1 mm (Figs 22–24).