Malthodes parvus Kazantsev, 1995

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 : 366-369

Malthodes parvus Kazantsev, 1995

( Figs. 4–6 , 25–30 , 32 )

Malthodes parvus Kazantsev, 1995: 102 , figs. 9–11; Kazantsev, 2004: 30 (in list); Kazantsev & Brancucci, 2007: 292 (in list); Kazantsev, 2011: 403 (in list).

Malthodes sp.: Mizuno & Hosoda, 2010: 95.

Materials examined. Japan: HOKKAIDO Lake Shikaribetsu , 25.vii.1997, NT (1 male, NTC) ; same data as above, R. Matsumoto (2 males, NTC) . Mts. Daisetsuzan, Mt. Upepesanke , 7.viii.2002, N. Yasuda (1 male, SIC) . HON- SHU (Niigata Pref.) S-Echigo, Mt. Shorenge [Korenge], 25.vii.1961, K. Baba (1 male, MSC). (Nagano Pref.) Mt. Kisokoma—Mt. Soraki [Utsugi], 1.viii.1986, S. Takeda (1 male, SIC) . Tokugô Pass , 31.vii.1959, M. Sato (1 male, MSC). (Yamanashi Pref.) Ashiyasu Vil., Kitazawa Pass , 27.vii.1959, Y. Miyatake (2 males, ELKU; 1 male, NTC) ; 30.vii.2001, T. Ueno (1 female, NTC) . Ashiyasu Vil., Hirokawara—Kitazawa Pass [Minami-Alpsrindô], 19.vii.1997, NT (3 males and 1 females, NTC) ; 20.vii.1997, NT (1 male, NTC) . Mt. Ogawa, Hacchô-daira , 2–3.viii.1985, K. Mizuno (1 female, SIC) . Mt. Ogawa (Mizugaki—Hacchô-daira), 19–20.vii.1986, K. Mizuno (1 male, SIC) . Sudama-chô, Mizugaki Cottage—Hacchô-daira, 13.vii.2001, NT (2 males, NTC) . Mt. Hôô, Hôô-goya , 20.viii.1989, K. Hosoda (1 female, SIC) ; 29.vii.1991, K. Hosoda (2 males and 2 females, SIC) ; 30.vii.1995, K. Mizuno (1 male, SIC) .

Diagnosis. Body ( Figs. 4–5 ) relatively large, dark brown to black; pronotum ( Fig. 6 ) subquadrate and mostly lustrous on surface. Male: abdominal tergite X subquadrate in dorso-caudal view ( Fig. 27 ), obliquely joined to tergite IX at just before apex of tergite IX in profile ( Fig. 25 ); abdominal sternite IX ( Fig. 26 ) bifurcate in apical half. Aedeagus ( Figs. 28–30 ): basophysis of tegmen slender, flattened, hooked dorso-basally at apex, without a small projection at the apico-ventral margin in profile; penis slender with a sub-triangular lamina in ventro-basal part in profile. Ovipositor ( Fig. 32 ): coxite nearly linguiform in apical portion, with a small digitiform lobe at apical part of mesal margin.

This species is closely related to M. guttifer Kiesenwetter, 1852 , being widely distributed from western Europe through Russia to Mongolia and East China ( Kazantsev & Brancucci 2007; Kazantsev 2011), but the body coloration is different and the basophysis of aedeagus lacks a small projection at the apico-ventral margin. It differs from other Japanese Malthodes by the conspicuously shiny and subquadrate pronotum.

Redescription based on Japanese specimens. MALE ( Fig. 4 ). Head black but reddish around clypeus; eyes dark brownish black to black; apical portions of mandibles, tibial spurs, and pretarsal claws reddish brown; maxillary and labial palpi, antennae, pronotum, scutellum, elytra and most of abdominal sternites dark brown though faintly reddish on pronotum, sometimes yellowish at posterior margin including hind angles and on abdominal sternites VIII and IX, and often dull yellowish at elytral apices; legs and ventral side of thorax often slightly browner than the above-mentioned parts, but yellowish around lateral ends of hind coxae and at apical parts of coxae and trochanters, and sometimes so at apical parts of femora or basal parts of tibiae; mouth parts other than the aforementioned parts orangish.

Body elongate, densely covered with dark brownish and recumbent pubescence, fitted with longish pubescence around clypeus; antennae and lateral areas of elytra sparsely intermingled with pale bristles; antennae, tibiae, tarsi, abdominal sternites VIII and IX, and abdominal tergite X covered with suberect bristles.

Head wider than long, 1.16–1.26 times wider than pronotum, explanate and arcuate with a faint indentation in the middle at apical margin of clypeus; surface lustrous; mandibles simple; eyes relatively small, interocular distance 2.70–2.97 times larger than radius of eye; antennae filiform and long, extending over elytral apices by about a quarter length of elytra, relative lengths of antennomeres from base as follows— 17.5: 10.0: 13.4: 16.7: 18.7: 16.9: 17.1: 15.4: 14.5: 13.2: 15.0.

Pronotum subquadrate, 1.12–1.33 times wider than long; disc convex medio-dorsally and lustrous but sometimes slightly matt around angles, somewhat granulate around hind angles, subtruncate or faintly arcuate anteriorly and weakly marginate at anterior margin, obtusely rounded at front angles, gently arcuate posteriorly and weakly marginate at posterior margin, obtusely rounded, slightly protruded laterally and weakly warped dorsally at hind angles, subparallel and weakly marginate but slightly narrowed posteriorly at sides. Pronotal hypomeron lustrous on surface.

Elytra 2.19–2.43 times longer than wide; surface weakly rugulose though relatively smooth around humeri and in apical portions, feebly marginate along sutural line, with a few rather undefined costae on each elytron.

Prosternum, meso- and metaventrites lustrous on their surfaces. Abdominal sternites somewhat rugulose but sternites VIII and IX relatively lustrous; abdominal tergite IX elongate, somewhat trapezoidal and feebly narrowed apically, gently arcuate apically at apical margin, obtusely rounded at apical angles, mostly flattened though curved ventrally in lateral areas on dorsum in dorsal view, with tergal bridles (sensu Brancucci 1980) partly produced ventro-posteriorly (“basal plates” in Liberti 2015, 2016) having gently rounded margins in profile; tergite X ( Fig. 27 ) subquadrate, faintly and shallowly emarginate at sides, rounded at apical angles, explanate and subtruncate in the middle or bisinuate at apical margin, mostly flattened though curved ventro-basally in latero-basal areas in dorso-caudal view, obliquely joined to tergite IX at just before apex of tergite IX, depressed at base on dorsum, and gradually tapered apically in profile; sternite VIII subtruncate on both sides, deeply and obtusely emarginate basally in the middle at apical margin; sternite IX ( Fig. 26 ) relatively slender, well sclerotized, gradually narrowed apically, bifurcate in apical half, subparallel at sides and slightly depressed on medio-longitudinal area in basal part in ventral view, slightly arcuate ventrally, weakly and obtusely produced dorsally just behind apex in profile.

Aedeagus ( Figs. 28–30 ) somewhat cymbiform in general appearance; sternal lobe of tegmen nearly oblong in outline, explanate and weakly arcuate laterally in basal halves and slightly narrowed apically in apical halves at sides, subtruncate at apical margin, and rounded at apical angles in ventral view, and gently convex ventrally in profile; tergal platelet of median lobe oblong, slightly arcuate laterally at sides, rounded at apical angles, and subtruncate with a faint projection in the middle at apical margin in dorso-basal view, convex dorso-basally and densely covered with suberect pubescence in apical part of apico-ventral side in profile; tergal lobe of tegmen gradually narrowed basally with rounded apex and swollen dorsally in basal half, concave medio-ventrally with triangular lobes (laterophyses) warped dorsally at sides in apical half, the lobes covered with pubescence on dorsal surface in dorsal view; basophysis of tegmen slender, flattened, projected dorso-apically, hooked at apex, and feebly arcuate ventroapically in basal part in profile, subparallel at sides in most part though arcuate medially in basal part and faintly curved medially at apex in caudal view; penis slender with a sub-triangular lamina in ventro-basal part in profile.

Body length: 3.0– 4.3 mm; width: 0.9–1.2 mm.

FEMALE ( Fig. 5 ). Similar to male, but body stouter than in male; abdominal sternites monotonously brownish. Head more gradually narrowed posteriorly behind eyes than in male; eyes small, interocular distance 4.07–4.35 times larger than radius of eye; antennae shorter, reaching about basal 5/8 of elytra, and relative lengths of antennomeres from base as follows:— 18.7: 10.0: 12.0: 14.3: 15.3: 13.8: 13.7: 12.4: 11.6: 11.1: 13.1. Pronotum ( Fig. 6 ) slightly wider, 1.26–1.33 times wider than long, and 1.00–1.06 times wider than head. Elytra 2.02–2.32 times longer than wide.

Copulatory depression not recognized on any apical abdominal tergites; abdominal tergite VII rectangular; tergite VIII as large as tergite VII in size, but shallowly emarginate posteriorly in the middle at basal margin, subparallel in basal 1/3 and obliquely narrowed apically in apical 2/3 at sides, subtruncate at apical margin; abdominal sternite VIII rather broad, narrowed apically in apical 1/3 at sides, explanate and subtruncate on both sides with a linguiform emargination in the middle at apical margin. Ovipositor ( Fig. 32 ): paraproct semicylindrical, weakly dilated basally, subtruncate to feebly arcuate apically at apico-dorsal margin in dorsal view, and widely rounded at apical angles in profile; coxite somewhat triangulate in outline, arcuate medially and warped ventrally at mesal margin, with a small lapel at base and a small digitiform lobe at apical part of mesal margin, concave in basal portion, nearly linguiform and feebly warped dorsally in apical portion.

Body length: 2.9–3.7 mm; width: 1.0– 1.1 mm.

Distribution. Japan (Hokkaido, Honshu); Russian Far East (Primorskij Kraj).

Remarks. This species is here recorded from Japan for the first time. We propose that the Japanese name of this species is “Tsuyamune-kurochibi-jôkai”.

Figures

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 25–30. Malthodes parvus Kazantsev, male. 25, apical portion of abdomen, lateral view; 26, abdominal sternite IX, ventral view; 27, abdominal tergite X, dorso-caudal view; 28–30, aedeagus (28, dorsal view; 29, lateral view; 30, ventral view). The arrow representations are the same as those in Figs 10–15 (one in the upper margin for Fig. 25; the other one in the right margin for Figs 26–30).Abbreviations: bp, basophysis; lp, laterophysis; pe, penis; sl, sternal lobe; tb, tergal bride; tl, tergal lobe; tp, tergal platelet. Scales: 0.2 mm (Figs 25–26); 0.1 mm (Figs 27–30).

FIGURES 31–32. Ovipositors of Malthodes spp., ventral view. 31, Malthodes okushimai Imasaka & N. Takahashi, sp. nov.; 32, Malthodes parvus Kazantsev. The arrow representation is the same as that in Figs 11–15. Abbreviation: p, proctiger. Scales: 0.2 mm.