Hexarhopalus (Leprocaulus) binhanus ( Pic, 1922 ), 2025

Hexarhopalus (Leprocaulus) binhanus ( Pic, 1922) comb. n. ( Figs 4a–d View FIGURE 4 , 6a, i View FIGURE 6 )

Derosphaerus binhanus Pic, 1922: 26 .— Gebien (1941): 353 (648).

Type material. Lectotype ♂ ( MNHN, designated here): TYPE {red, printed} // Hoa—Binh [province] / ( Tonkin) {white, handwritten} // binhanus n. sp. {white, handwritten} // Museum Paris / Coll. M. Pic {white, printed} // LECTOTYPE / Derosphaerus / binhanus Pic, 1922 / des. L. Purchart, 2023 {red, handwritten}.

Additional material. Vietnam: (1 BMNH): LACTHO / Tonkin / de Cooman // 385 // Necrobioid. / gibbicollis / Fleut. // Necrobioides / gibbicollis / Fleut.; (4 ♂ + 4 ♀ MNHN) : LACTHO / Tonkin / de Cooman // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 BMNH): Tonkin / Laos / [the other side of the label] 386 // Necrobioid. / gibbicollis / Fleut. // Derosphaerus ! / det. Schawaller 2010 ; Thailand: (1 BMNH): THAI, 9.–13.IV.1991 / THIMONGHTA, 350 m / 15 02 °N 98 35 °E / P. Pacholatko leg GoogleMaps ; Laos: (1 ♀ MNHN): JAN 1963 / Vientiane / LAOS — A. Baudon // cum typo / comparat / Derosphaerus / binhanus / P. ARDOIN det. 1963 // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♀ MNHN) : 17.VII.1975 / Khongsédone / LAOS / J. Rondon leg. // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♂ MNHN): 5.VII.1965 / Paksong / Sud LAOS / J. Rondon leg. // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♂ MNHN): 8.VI.1965 / Phou Khao Khouai / Vientiane — LAOS / J. Rondon leg. // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♂ MNHN): 30.X.1966 / Ban Van Eua / Vientiane — LAOS / J. Rondon leg. // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♀ MNHN): 1.V.1964 / Phontiou / Thakek — LAOS / J. Rondon leg. // MUSEUM PARIS / COL. P. ARDOIN / 1978; (1 ♀ MNHN) : VII.1964 / Plaine des Jarres / LAOS — A. Baudon; (2 MNHN): Boa Binh / Tonkin // Derosphaerus / binhanus // Museum Paris / Coll. M. Pic.

Remark. I had the opportunity to study the type of Derosphaerus binhanus Pic, 1922 deposited in MNHN together with a smaller series of non-type specimens belonging to this species. I found out that it actually belongs to the genus Hexarhopalus due to constantly present oblique indentation in the posterior corners of the pronotum, which can be quite inconspicuous but obvious. Therefore, I transfer this species from Derosphaerus to Hexarhopalus as H. binhanus ( Pic, 1922) comb. n.

In additional material the locality “ Tonkin Laos ” is stated in one specimen ( BMNH), but Tonkin in Laos does not exist. I assume that the collector of this specimen did not record accurate locality data while travelling in these two areas which were parts of the former French Indochina. Therefore, he probably just labelled this specimen with the locality label Tonkin Laos.

Differential diagnosis. In general appearance H. binhanus ( Pic, 1922) comb. n. can, owing to the convex elytral interstriae without tubercles and smooth, glabrous pronotum, only be confused with H. kaszabi Bečvář & Purchart, 2008 (Borneo) and H. lilligi Bečvář & Purchart, 2008 ( Thailand, Laos). From both species, however, it differs by shallow and extremely weakly developed lateral oblique indentation in posterior pronotal angles ( Fig. 6i View FIGURE 6 ), which is well developed and deep in the latter species ( Figs 6k, l View FIGURE 6 ). In addition, it differs from H. lilligi by brown colour and finer punctation of the pronotal surface (in H. lilligi the colour is black and pronotal surface coarsely punctate Fig. 6d View FIGURE 6 ). Compared with H. kaszabi , it further differs by completely obliterated lateral edge of pronotum whereas it is very shortly developed in posterior pronotal angles in H. kaszabi ( Fig. 6k View FIGURE 6 ).

Redescription. Size of lectotype 10.8 × 4.1 mm. Winged, brown, dull shiny. Body elongate subcylindrical, glabrous ( Figs 4a–c View FIGURE 4 ).

Head glabrous, narrower than pronotum in ratio 1:1.48 ( Fig. 6a View FIGURE 6 ). Vertex shagreened and therefore dull. Frons shagreened and finely punctate, punctures´ diameter smaller than diameter of eye facet. Clypeus shiny and finely but densely punctate with punctures´ diameter same as of eye facet, anterior margin emarginated. Labrum transverse, reddish-brown, keeled transversally, with long yellow setae anteriorly. Frontoclypeal suture well developed, rather shallow, reaching clypeal margin. Ocular sulcus moderately deep, distance between eyes 1.09× wider than their transverse diameter (DV). Antenna pale brown, pubescent, 1.05× longer than pronotum.

Pronotum shagreened, dull-shiny, slightly transverse, PW:PL ratio is 1:1.13, broadest at middle ( Fig. 6a View FIGURE 6 ). Entire surface of pronotum irregularly and densely punctate, with punctures´ diameter approx. as large as eye facet and intervals between punctures same or 2× larger than their diameter. Oblique indentation in posterior angles extremely slightly developed, almost obliterated, very shallow ( Fig. 6i View FIGURE 6 ). Anterior margin of pronotum straight, only very slightly rimmed at anterior corners. Sides of pronotum rounded. Base of pronotum completely and deeply rimmed. Prothoracic hypomeron smooth, shagreened, dull, impunctate, not separated from pronotal disc by lateral groove which is completely absent.

Elytra shagreened, 1.85× longer than its width, 3.4× longer and 1.54× wider than pronotum, dorsally flattened (LV), slightly dilated posteriad, broadest at posterior third ( Fig. 1a–b View FIGURE 1 ). Declivity of elytra before apex moderate (LV). Elytral humeri well developed. Elytral striae deep with row of separated deep rounded punctures. All elytral interstriae convex. Base of elytra not rimmed. Scutellum triangular ( Fig. 6a View FIGURE 6 ).

Prosternum brown, shagreened, glabrous, dull. Prosternal process with distinct and rather deep midlongitudinal groove between procoxae, apically broadly rounded, slightly narrower than procoxa. Mesosternum brown, shiny, glabrous; in middle with shiny midlongitudinal carina. Metasternum brown, shagreened, dull-shiny, very finely, shallowly and sparsely punctate.Approximately 1.7× longer than mesocoxa.Abdominal ventrites brown, shagreened, dull-shiny, finely, shallowly and rather densely punctate, glabrous.

Legs brown, simply, finely and densely punctate. Femora claviform, glabrous. Tibiae straight, finely pubescent. Tarsi dorsally pubescent.

Variability of size: 9.5–11.9 × 3.6–4.4 mm.

Distribution. Vietnam. New records for Thailand and Laos.