Pastillus eminentithorax

Hisamatsu, Sadatomo, 2013, A review of the Japanese Cybocephalidae (Coleoptera: Cucujoidea), Zootaxa 3616 (3), pp. 253-267 : 264-266

Pastillus eminentithorax S-T. Hisamatsu, sp. nov.

Figs 1 D, 2A, C, 3A, 8

Type series. Holotype: 3, (RYUKYU: JAPAN) / Shirahama / Iriomote / 10. X. 1988 / M. Sakai leg. / HOLOTYPE / Pastillus eminentithorax / S-T. Hisamatsu, 2011 /. Paratypes: 20 exs.: [MIYAGI] 1 ex., Takiyama Park, Yamotochô, 2. VIII. 2009, T. Ozaki leg. [SAITAMA] 1Ƥ, Urawa City, 18. VI. 1957, H. Kajimura leg. [KANAGAWA] 1Ƥ, Mt. Kôbô, 22. IV. 1989, Y. Hirano leg. [TOKYO] 1Ƥ, Sanbancho, 4. X. 2008, K. Masumoto leg.; 1Ƥ, Shimizudani, Megasaki City, 16. III. 2001, Y. Hirano leg. [AICHI] 1Ƥ, Araike, Tempaku Ward, Nagoya City, 6. V. 1995, H. Yoshitomi leg.; 1Ƥ, Hadenoshi-Hassawa, 27. IV. 1996, Y. Hirano leg. [HIROSHIMA] 1Ƥ, Mt. Haigamine, Kure City, 8. IX. 2002, I. Okamoto leg. [SHIMANE] 1Ƥ, Kushiro-chô, Masuda City, 15. V. 1996, Y. Hirano leg. [EHIME] 1Ƥ, Ohmishima Is., 16. VII. 1959, M. Miyatake leg.; 6Ƥ, Shiroyama, Matsuyama City, 5. V. 1973, M. Sakai leg. [ KOCHI] 1Ƥ, Cape Ashizuri, 13. VI. 1961, S. Hisamatsu leg. [NAGASAKI] 1Ƥ, Unzen Spa, 5. VI. 1967, S. Hisamatsu leg.; 1Ƥ, Mt. Fugen~Mt. Myoken, 7. X. 1970, S. Hisamatsu leg. [KAGOSHIMA] 1Ƥ, Sendai City, 28~ 24. III. 2001, Y. Hirano leg.

Type depository. The holotype and 15 paratypes are deposited in the EUM. Five paratypes are deposited in PCYH.

Etymology. The specific name means “projecting pronotum (eminens + thorax)”, which is derived from the strongly projecting lateral margins of the pronotum in lateral aspect.

Diagnosis. Body strongly convex, almost hemispherical. Antennae ( Fig. 8 K) 10-segmented, with 2-segmented club; scape strongly enlarged, widest at middle. Lateral margins of pronotum in lateral view strongly projecting. Inter-metacoxal lobe of abdominal sternite III ( Fig. 2 A) strongly narrowed.

Description. Length 1.66–1.83 (1.78) mm (n = 5), width 0.70–0.80 (0.61) mm (n = 5), height 0.63–0.70 (0.67) mm (n = 5).

Male. Body highly convex and shining, contractile; dorsal disc almost glabrous. Coloration black to dark brown; antennal segments 2–8, maxillary and labial palpi, prosternum, mesoventrite, procoxae, protrochanters, profemora, mesocoxae and mesotrochanters yellowish.

Head wide; vertex distinctly punctuate; interspaces smooth; apical margin distinctly bordered, with deep emaginations for reception of antennal scape. Labrum ( Fig. 8 G) about as wide as long, with truncate apical margin. Eyes large, but scarcely visible in ventral aspect. Mentum ( Fig. 8 J) trapezoidal. Antennal grooves long and deep. Antennae ( Fig. 8 K) 10-segmented, with 2-segmented club; scape strongly swollen, widest at middle; approximate ratio of each segment (n = 1) is 2.55: 1.96: 1.25: 1.11: 1.24: 1.02: 1.05: 1.00: 1.51: 4.33.

Pronotum strongly convex, 1.70–1.78 (1.74) times as wide as long (n = 5); lateral margins strongly projecting in lateral aspect; dorsal disc with minute punctures and short recumbent sparse setae; interspaces smooth. Scutellum ( Fig. 2 C) triangular, with acuminate apex.

Elytra strongly convex in lateral aspect, conjointly 1.17–1.24 (1.19) times as long as wide (n = 5), 1.53–1.73 (1.61) times as long as pronotum (n = 5); disc ( Fig. 3 A) with minute, uniform punctures; interspaces smooth. Prosternum strongly carinate at middle. Metaventrite ( Fig. 2 A) depressed, short, about as wide as metafemora; disc asetose. Inter-metacoxal distance strongly narrow, separated by 1.28 (1.28) times as wide as inter-mesocoxal distance (n = 1). Inter-mesocoxal distance strongly narrowed. Abdominal sternites ( Fig. 2 A) covered with long, recumbent yellowish setae; inter-metacoxal area of abdominal sternite III strongly narrowed, triangular; femoral lines ( Fig. 2 A) strongly expressed beyond anterior margin of abdominal sternite III. Legs ( Fig. 8 D–F) with protibiae slender, inner and outer margin slightly sinuate; metatibiae flat and wide, strongly widened from basal third to apex. Claws simple.

Male genitalia with tegmen ( Fig. 8 A) in ventral view constricted at middle; anterior margin of tegmen with two projections. Median lobe ( Fig. 8 B) in ventral view subparallel-sided from base to middle, abruptly attenuate anteriorly; anterior margin more or less truncate in ventral aspect; apico-lateral corners with tuft of long setae in ventral aspect. Internal sac sclerites of male genitalia ( Fig. 8 C) as figured.

Female. Apical margin of abdominal tergite and sternite VII rounded. Ovipositor ( Fig. 8 I) elongate and slender; coxites feebly sclerotized, deeply cleft and appearing separated, apex of stylus with 3~4 setae; 5~6 setae present along apico-lateral margin. Spermatheca ( Fig. 8 H) C-shaped, spermathecal gland distinct, sperm duct coiled.

Bionomics. Biology unknown.

Distribution. This species is known from Honshû, Shikoku, Kyûshû, and Iriomote Island, Japan.

Remark. This new species is similar to Pastillus conflexus Endrödy-Younga , known from Sierra Leone, but can be distinguished from the latter by the ten-segmented antennae and peculiar shape of male genitalia. Pastillus eminentithorax sp. nov. is widely distributed in Japan. Twenty-one specimens were examined, with only one male found, which was collected on Iriomote Is., Okinawa Pref. This preliminary data on sex ratios may indicate a parthenogenetic lifestyle of the species. However, further examination and field data are needed to corroborate this hypothesis.

Pastillus is a small genus, consisting of three species, with previously known distributions limited to localities in the Afrotropical Region. This new species represents the fourth species of the genus, and is the first recorded from Palaearctic Region.

Figures

FIGURE 1. Lateral habitus of Cybocephalidae spp. A, Cybocephalus (C.) nipponicus Endrödy-Younga, 1971 (male, Tokunomori, Ehime Pref.); B, Cybocephalus (C.) politissimus Reitter, 1898 (male, Yoshiji-chô, Shimane Pref.); C, Cybocephalus (C.) chlorocapitis sp. nov. (holotype, male, Amami Is.); D, Pastillus eminentithorax sp. nov. (paratype, female, Araike, Aichi Pref.). Scale bars = 1 mm.

FIGURE 2. Pastillus eminentithorax sp. nov. and Cybocephalus (Cybocephalus) nipponicus Endrödy-Younga, 1971. A, C, Pastillus eminentithorax; B, D, Cybocephalus (C.) nipponicus. A, B, body, ventral view; C, D, scutellum. A = Mt. Kôbô, Kanagawa Pref.; B, D = Morimatsu, Ehime Pref.; C = Mt. Haigamine, Hiroshima Pref.

FIGURE 3. Elytral punctuation of Pastillus eminentithorax sp. nov. and Cybocephalus (Cybocephalus) spp. A, Pastillus eminentithorax sp. nov.; B, Cybocephalus (C.) nipponicus Endrödy-Younga, 1971; C, D, Cybocephalus (C.) politissimus Reitter, 1898. A = female, Mt. Haigamine, Hiroshima Pref.; B = male, Morimatsu, Ehime Pref.; C = male, Yakushima Is.; D = male, Sugitate, Ehime Pref.

FIGURE 8. Pastillus eminentithorax sp. nov. A, tegmen, ventral view; B, median lobe, ventral view; C, sclerite of internal sac; D, left protibia; E, left mesotibia; F, left metatibia; G, labrum; H, spermatheca, spermathecal gland, and sperm duct; I, ovipositor; J, mentum; K, right antenna. A – C = holotype, Amami Is.; D – K = paratype, Ohmishima Is., Ehime Pref. Scale bars = 0.1 mm.