Madrasostes tonkinense ( Paulian, 1945 )

Ballerio, Alberto & Maruyama, Munetoshi, 2025, Review of Madrasostes Paulian, 1975 (Coleoptera: Hybosoridae: Ceratocanthinae) from Vietnam, with remarks on its generic limits, Zootaxa 5661 (3), pp. 420-430 : 427-429

Madrasostes tonkinense ( Paulian, 1945)

( Fig. 5 )

Cloeotus tonkinensis Paulian, 1945: 31 (original description)

Madrasostes tonkinenses : Paulian 1978: 488 (incorrect subsequent spelling, new combination, redescription and key) Madrasostes tonkinense : Ocampo & Ballerio 2006: 188 (checklist); Marshall 2018: 354 (photos of alive adult)

Type locality. Hoa Binh ( Tonkin) .

Material examined. Vietnam: Holotypus ( Fig. 5G–J ), sex unstated (BMNH): type / Tonkin A. de Cooman B.M. 1929-299 / Hoa Binh Tonkin de Cooman / Cloeotus tonkinensis det. R. Paulian 1937 / Madrasostes tonkinense (Paul.) R. Paulian det.; 1 ♀: Ba Be 220m alt. Cao Bang prov. / [N. Vietnam] 12.V.1998 S. Nomura leg. (NSMT); 1 ♀ ( Fig. 5A ): Ban Xa Lenh 890 m, Xa Pa Co, Huyen Mai Chau, Hoa Binh Prov. / [N. Vietnam] 20.VI.1997 S. Nomura leg. (NSMT); 1 ♀: Vietnam: Hoa Binh province, Lac Son district, c/o Ngoc Son Ngo, Luong Nature Reserve, 200 m, at light, 20°23’55”N 105°22’15”E, 11.V.2024, leg. L. Bartolozzi, I. Pukhkalo, E. Orbach (num. Magazz. 3147) (MZUF); Laos ( Fig. 5B–D ): 1 ♀: Laos north, 5-11.V.1997, 20 km NW Louang Namtha, N21°09.2 E 101°18.7 al. 900 m, E. Jendek & O. Šauša leg. (ABCB); Thailand: 1 ♂: NW Thailand 23- 31.5.1991, Mae Hong Son, Ban Si Lang, 1200 m, J. Horák leg. (Coll. David Král, National Museum, Prague, Czechia).

Redescription. Size: HL = 1.25 mm; HW = 1.70 mm; PL = 1.72 mm; PW = 3.00 mm; EL = 3.27 mm; EW = 3.00 mm. Large-sized Madrasostes . Volant. Body weakly convex. Metallic green with red and gold sheen, dorsum almost glabrous (50×) with only few fine short erect sparse setae, underside, tarsi and antennae dark reddish-brown.

Head: W/L ratio = 1.35; subpentagonal, clypeal apex obtuse, apical projection absent, sides broadly rounded; genal canthus distinct not reaching occipital area, dorsal ocular area present, interocular distance about 13 times maximum dorsal ocular area width, inferior ocular area large, genae acute, slightly protruding outwards, genal suture indistinct; head dorsal surface covered by large and impressed transverse comma shaped punctures, all them centripetally oriented, punctation relatively dense with an impunctate area on frons, vertex marked by a continuous transverse impressed line, fore margin of clypeus with two or three transverse large lines. Pronotum: subrectangular (dorsal view) (W/L ratio = 1.79), convex, fore angles sinuated at both sides, pronotal punctation uniformly covering pronotal surface as follows: disc covered by small horseshoe-shaped punctures mixed to short impressed (foveolate) comma-shaped punctures, all punctures with opening directed forwards, punctation sparse (interpunctural distance in the majority of cases larger than punctural diameter although some punctures are closer to each other), sides covered by larger horseshoe-shaped punctures with opening directed outwards, punctation denser (interpunctural distance distinctly shorter than punctural diameter). Scutellum : base smooth with two impressed transverse lines, remaining surface with impressed irregular punctation, larger and sparser proximally and denser and smaller distally. Elytra : slightly longer than wide (W/L ratio = 0.87), subovoidal (dorsal view), moderately convex; humeral callus present; elytral surface uniformly covered by horseshoe-shaped punctures of variable size (with opening directed downwards) mixed to small comma-shaped punctures and to simple fine punctures, the latter denser on distal third, punctures on basal third and along elytral suture larger, denser (sometimes touching each other) and more impressed, punctures on disc sparser (interpunctural distance larger, often twice, than punctural diameter), distal third with a longitudinal line marking the sutural stria and with denser and larger punctures with respect to elytral disc, with a larger number of simple fine punctures, distal third with three very weakly raised and smooth longitudinal carinae, sides with two irregular longitudinal lines; inferior sutural stria deep and complete, striated articular area hardly visible in lateral view, relatively narrow and short; marginal area medium-sized; elytral articular process developed, smooth and shiny, with a deep line bordering scutellar sides. Wings: fully developed. Sexual dimorphism : spur of protibiae in males is more bent than in females. Males have the inner apical spur hooked (bent inwards at a right angle and pointed), whereas in females both apical spurs of mesotibiae are straight Male genitalia: aedeagus (L = 1.4 mm) with parameres as in Fig. 5F , spiculum gastrale (L = 1.2 mm) as in Fig. 5E .

Distribution and habitat. The distribution of this species covers much of Northern Indochina ( Thailand, Laos and Vietnam).

Remarks. Madrasostes tonkinense is similar to M. franzi Paulian, 1978 (known from Thailand) and M. feae (Gestro, 1898) (known from NE India, Nepal, Myanmar, Thailand and Cambodia), with whom shares a simple dorsal sculpturing without carinae or tubercles (first author’s unpublished data). The aedeagal morphology too (the shape of parameres in lateral view) suggests similarities with the aforementioned species.

Figures

FIGURE 5. Madrasostes tonkinense (Paulian, 1945). A. Distended adult from Vietnam (Ban Xa Lenh) in dorsal view. B. Rolled-up adult from Laos (20 km NW Louang Namtha) in ventral view. C. Rolled-up adult in dorsal view. D. Rolled-up adult in lateral view. E. Specimen from Thailand (Mae Hong Son), spiculum gastrale. F. Same specimen, aedeagus in lateral view. G–J. Holotypus in BMNH and its labels.