Nitorus mediomaculatus ( Pic, 1913 )

Telnov, Dmitry, 2024, New species and records of Anthicidae Latreille, 1819 (Coleoptera) from Taiwan with a key to Asian Nitorus Telnov, 2007 species with gibbose pronotum, Zootaxa 5507 (2), pp. 285-312 : 289-293

Nitorus mediomaculatus ( Pic, 1913) stat. rest., comb. nov. ( Figures 3–5 )

Pic (1913: 130) as ‘ Leptaleus trigibber Mars. var. nov. mediomaculatus ’; Krekich-Strassoldo (1926: 96), considered a colour morph of L. trigibber Marseul, 1876 : ‘…sind auf Färbungsnuancen aufgebaut und nicht begründet’, but a formal new synonym was not introduced; Miwa (1931: 181) checklist, as ‘ Leptaleus trigibber var. mediomaculatus Pic’; Nomura (1965: 146), record from Nantou County, as ‘ Leptaleus mediomaculatus ’; Telnov (2003: 289) regional catalogue, listed as a synonym of Pseudoleptaleus trigibber without a introducing a formal synonym; Chandler et al. (2008: 444), checklist, listed as a synonym of N. trigibber ; Telnov (2020: 592), checklist, listed as a synonym of N. trigibber .

Type material examined. Lectotype ♀ [designated herewith] MNHN: Hokutó Formosa [printed] III [handwritten] H. Sauter,1912 [printed] // type [handwritten] // Leptaleus trigibber var. mediomaculatus Pic [handwritten] // SYNTYPE [printed, label red] // SYNTYPE Leptaleus trigibber var. mediomaculatus Pic, 1913 [printed] // MNHN, Paris EC30462 [printed, supplemented with a QR code]. Described from an unspecified number of specimens. The lectotype designation is made to maintain nomenclatural stability considering the new status of the taxon proposed herein.

Additional material examined. 1♀ HMNH: TAIWAN, Nantou county, Mong Gwu , 14 km E of Puli, 24°1.367’ N, 121°5.063’ E, // 850 m, swept from vegetation, 20.IV.2002, leg. D. A. Anstine, Gy. Fábián & O. Merkl [printed] ; 17♂ ♀ BMNH: TAIWAN, Nantou County N24°02.530’; E121°12.555’ beating etc. 1920m 6.viii.2008 M.V.L. Barclay, H.Mendel & R. Ewers BMNH (E) 2008-85 [printed] ; 1♂ BMNH: TAIWAN, Nantou County 0.6km SE of Lushan , 1165m N24°01.035 E121°11.308 at light, 6.viii.2008 H.Mendel & MVL Barclay BMNH (E) 2008-85 [printed] .

Measurements. Male, total body length excluding partially exposed terminalia 2.35 mm; head length 0.5 mm, head width across compound eyes 0.5 mm, pronotal length 0.55 mm, maximum pronotal width 0.35 mm, minimum pronotal width in basal half 0.2 mm, elytral length 1.3 mm, combined maximum elytral width across midlength 0.8 mm. Selected males 2.5 mm, selected females 2.5–2.8 mm long.

Redescription. Male from Lushan, Taiwan. Head pale rufous-brown, pronotum yellowish rufous. Elytra yellowish to yellowish brown, humeri and narrow postbasal area black to brown, wide median area black to brown, dark colouration not touching lateral margins of elytra; smaller preapical median area also black to brown; both dark spots connected by narrow strip of dark colouration along suture. Elytral base, apex and lateral margins pale yellow to yellowish brown. Ventral head and pterothorax yellowish brown to rufous.Abdomen dark brown.Antenna yellowish brown, terminal antennomere darkened. Maxillary palpus yellowish brown. Legs yellowish, distal portion of each tibia darkened. Head elliptical, about as long as wide, slightly convex in dorsal aspect, glossy. Labrum subtruncate at anterior margin. Frontoclypeal suture present, nearly straight. Compound eye moderate, strongly protruding from lateral outline of head, about as long as converging tempus. Head base narrowly rounded. Head dorsal punctures moderate, rather sparse, deep. Intervening spaces smooth and glossy, as wide as to 3× as wide as punctures. Dorsal cranial setae yellowish, sparse, rather short, appressed, inconspicuous. Antenna extending towards postbasal transverse impression of elytra when directed posteriad, not or hardly thickened in apical half. Antennomere three about 1.4× as long as antennomere two.Antennomeres 4 and 5 about same length, each about 1.2× as long as antennomere three.Antennomeres 8–9 slightly widened distally. Penultimate antennomere subcylindrical, somewhat shortened. Terminal antennomere elongate, pointed, about 1.6–1.7× as long as penultimate antennomere, distinctly shorter the combined length of antennomeres 9–10. Penultimate maxillary palpomere short, about as long as wide, lobate at mesal margin. Terminal maxillary palpomere strongly securiform. Cranial ‘neck’ less than one third head width across compound eyes, densely punctured, moderately glossy. Pronotum longer than wide, distinctly narrower than head across eyes, broadly rounded at anterior margin. Pronotal disc glossy, bigibbose in dorsal aspect with deep, saddle-like discal impression separating anterior and basal lobe of pronotum. Lateral margins of anterior lobe broadly rounded, of basal lobe—subparallel. Anterior pronotal rim distinct, wide dorsally, laterally and ventrally. Antebasal sulcus wide dorsally and laterally. Pronotal punctures on anterior lobe smaller and sparser than those on head, intervening spaces glossy and glabrous, generally much larger than punctures. Basal lobe with large and dense but shallow punctures, intervening spaces glossy and glabrous, narrower than to as wide as punctures. Lateral sides of anterior lobe glossy and glabrous, nearly impunctured, of basal lobe—glossy and glabrous, with dense subparallel longitudinal wrinkles. Pronotal setae as those on head, appressed. Scutellar shield lanceolate, apically acutely pointed, glossy and glabrous. Elytra elongate, about 1.6× as long as wide, widest at midlength, dorsally flattened. Postbasal transverse impression shallow but distinct. Humerus broadly rounded. Apical sutural angle rounded. Elytral surface glossy and smooth, punctures small, shallow, moderately dense. Intervening spaces smooth and glossy, much wider than punctures. A yellowish, short, slightly curved, nearly appressed seta raises from each puncture. Scattered, much longer erect tactile setae on elytral disc. Metathoracic wing fully developed (functional). Long setae of mesanepisternum visible in dorsal view from beneath elytral humeri. Legs long and slender, moderately densely, appressedly setose. Meso- and metatibia slightly thickened in distal third. Metatibia slightly arched in dorso-ventral aspect. Tibial terminal spurs not observed (not present?). Basal metatarsomere longer than combined length of remaining metatarsomeres. Penultimate tarsomeres bilobate. Tergite VII truncate at posterior margin ( Fig. 4A ). Morphological sternite VII broad, rounded at posterior margin ( Fig. 4B ). Morphological tergite VIII rounded at posterior margin ( Fig. 4C ). Morphological sternite VIII narrow, broadly rounded at posterior margin ( Fig. 4D ), sternite IX Y-shaped, arms short ( Fig. 4E ). Aedeagus ( Fig. 4F‒H ) elongate, apex trident-shaped.

Sexual dimorphism. Females externally similar to males. Meso- and metatibia not or hardly thickened distally. Basal metatarsomere comparatively shorter, slightly longer than or as long as combined length of remaining metatarsomeres. Tergite VII subtruncate at posterior margin ( Fig. 5A ). Morphological sternite VII broadly rounded at posterior margin ( Fig. 5B ). Ovipositor as in fig. 5C.

Intraspecific variability. Intensity and colouration of pale elytral markings vary from yellowish brown to striking yellow. Size of pale markings vary among the specimens. Total body length varies from 2.35 to 2.8 mm.

Differential diagnosis. This species differs from N. trigibber (Marseul, 1876) and other congeners with bigibbose pronotum in the shape of the aedeagus and other features as in the Key below.

Ecology. Occurs at about 850–1920 m in forested area. Collected by beating and sweeping forest vegetation as well as at light.

Distribution. So far known from mountainous northern (Beitou District) and central (Nantou County) parts of Taiwan.

Figures

FIGURE 3. Nitorus mediomaculatus (Pic, 1913) stat. restit., comb. nov.A—Lectotype ♀, habitus, dorsal view [image courtesy C. Rivier]; B—♀ from Nantou County, habitus, dorsal view; B—ditto, lateral view [not to scale].

FIGURE 4. Nitorus mediomaculatus (Pic, 1913) stat. restit., comb. nov., ♂ from Nantou Country N24°02.530’; E121°12.555’. A—Tergite VII, dorsal view; B—Morphological sternite VII, ventral view; C—Tergite VIII, dorsal view; D—Morphological sternite VIII, ventral view; E—Morphological sternite IX, ventral view; F—Aedeagus; G—ditto, apex, magnified; H—ditto, median portion [not to scale].

FIGURE 5. Nitorus mediomaculatus (Pic, 1913) stat. restit., comb. nov. ♀ from Nantou Country N24°02.530’; E121°12.555’. A—Tergite VII, dorsal view; B—Morphological sternite VII, ventral view; C—Ovipositor [not to scale].