Merohister jekeli (Marseul, 1857)

(Figs 1-3; 10)

Hister jekeli Marseul, 1857: 417; 1862: 709; 1873: 220 (Japan: Kyu-shu, common in dung/manure).

Pactolinus jamatus Motschulsky, 1866: 169, synonymy in Harold (1877: 345).

Hister (Hister) jekeli – Bickhardt 1910: 44 (China, Japan). — Desbordes 1918: 385 (Japan; Korea; China: Yunnan).

Hister (Merohister) jekeli – Bickhardt 1913: 171 (Taiwan: Taihorin); 1917: 188 (China, Japan); 1918: 230 (note). — Miwa 1931: 57 (Taiwan: Horisha): Kamiya & Takagi 1938: 31 (list). — Ôsawa & Nakane 1951: 4 (note).

Merohister jekeli – Lewis 1915: 55 (Taiwan: Horisha). — Kryzhanovskij & Reichardt 1976: 304. — Mazur 1984: 201; 2011: 97 (catalogue). — Hisamatsu 1985: 226, pl. 41, f. 4 (note; photo). — Ôhara 1992: 378; 1994: 136. — Kapler 1993: 30. — Kim et al. 1994: 137 (Korea). — Ôhara & Paik 1998: 21. — Lackner et al. 2015: 102 (catalogue). — Zhou et al. 2022: 349 (redescription, figures). — Ôhara 2023: 73 (catalogue).

TYPE LOCALITY. — China, Shanghai.

TYPE MATERIAL. — Syntype. China • Shanghai; MNHN-EC-EC60885 (examined by Prof. Masahiro O’Hara).

MATERIAL EXAMINED. — India. Punjab • 15 ♂, 3 ♀; Amritsar; 31°36’2.05”N, 74°52’31.70”E; 8.IV.2022; J. Kumar col.; JASENT2022001-015, JASENT2022016 – 018; PUZEC • 5 ♂; Nawanshahr; 31°6’39.24”N, 76°9’36.42”E; 20.VI.2023; J. Kumar col.; JASENT2023001-005; PUZEC • 2 ♂, 20 ♀; Mullanpur Garibdas; 30°79’42.247”N, 76°74’90.211”E; 11.III.2023; J. Kumar col.; JASENT2023006- 007; JASENT2023008-027; PUZEC.

DISTRIBUTION. — India, Kuril Isls., Japan, Siberia, Far East Russia, Sakhalin, Korean Peninsula, Jeju Is., China, Taiwan, Philippines (Ôhara 1992; Mazur 2011).

DIAGNOSIS. — The labrum bears fine, dense anterolateral setal fringes. Mandibles are robust, inwardly curved, and terminate in a blunt apical tip; their surface is finely punctate, overlain by an alutaceous-reticulate ground sculpture that coarsens laterally.A straight subapical tooth lies anterior to a dense cluster of large, golden prosthecal setae. The protibia bears 3-6 denticles, while mesotibiae and metatibiae exhibit dual rows of denticles differing in size.

Male genitalia (Fig. 4D, E): The aedeagus (tegmen) is slender, laterally sclerotized, with inwardly curved median parameres and bulbous apical parameres. The basal piece forms a sclerotized ring encircling the posterior margin, connecting to the parameral basal margins. The tergite X displays denticulate lateral edges, with remaining areas brownish and heavily sclerotized.

REDESCRIPTION

Body (Fig. 1 A-E)

Oblong, moderately convex; matte black with faint metallic luster; surface uniformly clothed in coriaceous-reticulate microsculpture. Prothoracic setae golden, short, recumbent; elytra dark, shiny. Measurements provided in Table 1.

Head (Figs 1A, C, E; 2A)

Surface covered with minute punctures (Fig. 2A). Frontal stria complete,anterior contour rounded to straight,margins crenate, narrowly interrupted at midpoint in some specimens; frontal disc glossy, microsculpture coriaceous-reticulate (Figs 1A, C, E; 2A). Clypeus laterally expanded, margins broadly crenate; apex straight. Labrum finely punctate, anterolateral margins bearing dense fringes. Mandibles robust, inwardly curved, apically blunt; lateral surface coarsely punctate, prostheca depressed anterior to subapical tooth; prosthecal setae dense, elongate. Eyes large, convex, dorsolateral margin with row of erect setae (Fig. 1E). Postoccipital suture encircled by dense cluster of short setae (Figs 1B; 2A).

Pronotum (Figs 1A, C-E; 2B, D)

Pronotal disc clothed with reticulate ground sculpture intermixed with microscopic punctures (Figs 1A; 2B). Lateral portions bearing dense mixture of microscopic and larger punctures,extending narrowly toward anterior angles (Figs 1C; 2D); punctation denser anteriorly and posteriorly, sparser medially. Antescutellar region with short longitudinal punctures (Fig. 1A); marginal punctures sparse anteriorly, denser approaching pronotal lateral stria (Figs 1A; 2D). Marginal pronotal stria complete laterally, broadly interrupted behind head (Fig. 1C). Lateral pronotal stria deeply impressed, arcuate, weakly crenulate (Fig. 1A, C-E).

Elytra (Figs 1A; 2C)

Surface dark,shiny, densely punctate; marginal stria complete, finely crenulate (Figs 1A; 2C). Epipleural fossette with large, deep punctures forming longitudinal groove along lateral margin; epipleural stria marginal along apical half (Fig. 1C). External subhumeral stria arcuate; internal subhumeral stria reduced,obsolete.Dorsal striae 1-3 complete,finely impressed, none contacting basal margin (Figs 1A; 2C); interstitial punctures minute, aligned to contact anterior margins.Fourth stria variable in length, consistently shorter than third; striae 1-4 weakly arcuate laterally (Fig. 1A). Fifth stria abbreviated, confined to apical fourth, rarely extending beyond midlength. Sutural stria incomplete, extending from base to apical third. Striae margins externally crenulate throughout.

Hind Wings

C unbranched, extending to anterior wing margin; Sc unbranched,originating from first axillary sclerite;A connecting third axillary sclerite; shorter branch terminating medially before wing center; PCu contacting posterior wing margin, not extending to wing base; Cu and M diverging basally; Cu curving anterad toward anal vein; M extending posteriad toward Sc, connecting median plate (Fig. 5).

Propygidium and Pygidium (Fig. 1F)

Propygidium with reticulate ground sculpture intermixed with coarse, shallow, rounded punctures, diminishing in size posteriorly; pygidium clothed with punctures transitioning finer as density increases.Both regions bearing combined fine and coarse punctation.

Prosternum (Figs 1B; 2H)

Prosternal lobe apex rounded; disc sparsely punctate at center, punctures coarser laterally.Marginal stria crenulate, fading medially, connecting to lateral margins of lobe, occasionally encircling apex entirely. Parallel crenulate striae originating near basal margin, extending to posterior half. Prosternal keel broad; lateral stria nearly contacting prosternal suture.

Mesoventrite (Figs 1B; 2I, K)

Discal marginal stria crenulate, sinuate, bluntly angulate medially, shortened anteriorly,not attaining lateral metaventral suture. Disc with microscopic reticulate microsculpture. Meso-metaventral sutural stria straight, shortened anteriorly, failing to meet discal marginal stria but both intersecting post-mesocoxal stria.

Metaventrite (Figs 1B; 2I, K)

Lateral disc with coarse punctures and sparse setae. Lateral metaventral stria crenulate, irregular, uniting anteriorly with meso-metaventral sutural stria, extending posteriorly to intersect metepisternal stria. Longitudinal metaventral suture forming T-shaped junction with meso-metaventral sutural stria (Figs 1B; 2I).

Anepisternum (Fig. 2K)

Surface bearing light brown setae and coarse punctures.

Abdomen (Fig. 2I, J, M)

First abdominal ventrite trapezoidal (Fig. 2J); disc clothed with intermixed small and large punctures, occasionally arranged in striae-like rows anteriorly.Lateral stria of ventrite 1 deeply impressed, crenulate.Intercoxal disc bearing anterior row of coarse punctures, with sparse punctures extending toward longitudinal metaventral suture (Fig. 2I). Apparent abdominal ventrites 1-5, progressively narrower posteriorly (Fig. 2J, M).

Legs

Protibia (Figs 2E, N; 3A). Densely punctate, dark brown; dorsal margin with 4-6 denticles (Fig. 2E), surface reticulate, setae occasionally reduced. Protibial spur prominent at anterior angle (Fig. 3A); tibial groove margin bearing row of setae, sometimes reduced. Outer margin with row of robust setae near first denticle (Fig. 2E). Protarsus length c. 0.2 mm, base slender, glabrous. Claw ultimate segment cylindrical, length c. 0.3 mm. Anterior protibial stria flanked by 4-6-minute denticles (Fig. 2N); ventral strial region occasionally with diminished denticles or glabrous patches. Posterior protibial spur and ventral first denticle bearing 4 diminutive denticles (Fig. 2N); inner setal row present basad of stria.

Profemur (Fig. 3A). Coriaceous-reticulate microsculpture, punctate, subrectangular; dorsal setae arranged in scalene triangle; ventral surface with longitudinal groove, reticulate microsculpture basad. Distal end weakly swollen, stria originating dorsally, not attaining tibial base. Dorsal cluster of bristle-like setae near tibial articulation.

Mesotibia (Figs 2F; 3D). Dark brown; dorsal margin with two denticulate rows, denticle size increasing apicad. Outer surface with three setal rows (Fig. 2F): inner row ventrally positioned, irregularly spaced; outer row sclerotized,adjacent to dorsal denticles; middle row extending near mesotibial spur. Four apical spurs; tarsomere 1 with two pairs of spines, remaining tarsomeres each with single pair.

Mesofemur (Fig. 3C). Dark brown; posterior surface with dual setal rows; ventral setae restricted to basal half; dorsal setae sparsely distributed. Anterior surface punctate, glabrous.

Metatibia (Fig. 2F). Similar to mesotibia but elongate; dorsal denticles and setal rows proportionally extended.

Male genitalia Tergite VIII (Fig. 4A). Posterior margin medially arcuate, semicircular; anterior margin with deep, angulate median emargination.

Sternum VIII (Fig. 4A). Broadly ovate (1:1.2 L/W), glossy, glabrous. Margins ornamented by sclerotized, amber-tinted patches; anterior convex,sparsely setose; posterior emarginate with symmetrical, rounded lobes.Translucent golden-amber center grading to smoky margins;paired anterolateral fuscous blotches.

Spiculum gastral (Fig. 4C). More slingshot shape; bifurcate, moderately sclerotized; stem broad, slightly flattened, dividing into two slender, symmetrically divergent arms forming open V-angle; arms narrowing to rounded apices, inner margins smooth.

Tergite IX (Fig. 4B). Bilobed, broadly ovate;lobes symmetrical, weakly convex, apically tapered.Medial margin shallowly emarginate,forming narrow midline gap. Sclerotisation moderate to heavy, pigmentation grading from pale amber basally to golden-brown distally. Surface finely granulate, densely punctate medially and sublaterally; punctures small, shallow, uniform,interspersed with circular sclerites.Margins smooth, arcuate laterally and posteriorly; anterior margin broadly rounded, anterolateral angles weakly elevated.

Tergite X. Elongate, narrowly lobed; lobes spatulate to sub rectangular, apically tapered. Sclerotisation heavy, posterior margins amber; surface sparsely punctate laterally and apically,medially glabrous.Apical margins rounded to subacute, occasionally minutely emarginate; apex and lateral margins bearing sparse,sclerotized patches.Moderately membranous, margins finely denticulate.

Aedeagus (Fig. 4D). Slender, elongate (c. 5.6× longer than wide); lateral margins smooth, sclerotized, tapering apically. Basal piece forming complete sclerotized ring, posterior margin continuous with parameral bases; short, robust, suboval, heavily pigmented. Tegmen elongate, tubular, moderately sclerotized; surface smooth, glabrous. Median lobe strongly sclerotized,sculptured with complex armature, visible through tegmen as darker internal shaft, gradually tapering posteriorly.Parameres distinctly separated, apically lobate, bulbously expanded (c. 0.72× wider than median region); bilobed, symmetrical, lightly sclerotized; apices rounded, glabrous.