Clivina gracilicollis, Balkenohl, 2025

Clivina gracilicollis sp. nov.

( Figs 17 View FIGURES 15–26 , 52 View FIGURES 38–52 , 86 View FIGURES 85–96 , 112 View FIGURES 110–128 )

Type material. Holotype: ♂, with labels and data: white, black printed “BRUNEI-Temburong Belalong Field Res. C. Mix.Dipterocarp For. ~ 100m 2-8.5.95 Heiss ( CADW).

Paratypes: 1 ♂, 1 ♀, same data as holotype, the male with additional handwritten labels “helferi Gr. ” and “nov. Gen ??” ( CADW / CMBB) .

Description. Measurements. Body length 4.91–5.75 mm (ẍ = 5.13 mm *), width 1.28–1.56 mm (ẍ = 1.39 mm *), ratio L/W of pronotum 1.06–1.09 (ẍ = 1.08), ratio L/W of elytra 1.89–1.94 (ẍ = 1.92*); (*n = 3). Colour glossy, fuscous with ferruginous tinge. Supraantennal plate at margin slightly translucent. Antennae, mouthparts, and tarsomeres yellowish. Antennomeres darker from joint four onwards.

Head a fifth narrower than pronotum. Clypeus with central part straight, with slightly projecting sharp teeth laterally, separated from clypeal-wing by distinct notch; wing distinct, much less projecting as clypeal-teeth, somewhat rounded, separated from supraantennal plate by acute-angled notch, supraantennal plate with margin laterally convex, clypeus, wing, and supraantennal plate slightly reflexed margined. Supraantennal plate extended posteriorly into a widened blunt keel, separated from wing by small sharp furrow. Clypeus and frons developed as continuous moderately convex field, with few scattered micro-punctures, with indistinct flat impression centrally, separated from supraantennal plate and supraorbital carina by wide roughly reticulated furrow, with clypeal seta in front; supraorbital carinae short, blunt, with two supraorbital setigerous punctures at middle of eye level and at level of neck constriction. Neck constriction closed, formed by distinct step from frons, neck covered with irregular coreaceate-like structure. Eye small and flattened in dorsal view, main part situated ventrally, gena and supraorbital carina somewhat enlarged. Antenna elongate, reaching distinctly up to base of elytron. Labrum slightly convex, isodiametrically reticulated, seven-setose. Mentum isodiametrically reticulated, lobe with askew wrinkles, with increasing convexity anteriorly, cleft for palpomeres small, short, median tooth acuminated to tip, as high as lobes.

Pronotum ( Fig. 52 View FIGURES 38–52 ) conspicuously flattened frontal view, slightly convex in lateral view. Shape elongate, sub-cordate, longer than wide. Reflexed lateral margin slightly crenulate, slightly convex, widest at middle, teeth of posterior angles seemingly wider than margin; anterior angle widely rounded off, posterior angle marked by distinct anteriorly projecting tooth, with short concavity anterior to posterior angle; lateral channel narrow, isodiametrically reticulated, continuing up to base as narrow, straight margin. Median line engraved, complete, joining and surpassing anterior transverse line. Anterior transverse line distinct, complete. Disk covered with medium sized punctures, with fine transverse wrinkles, with isodiametric reticulation basally and laterally, with impression of posterior setigerous puncture distinct, conspicuously distant from margin. Lateral margin from posterior angle to flange of base slanted with angle of around 45°. Basal channel on flange conspicuously widened, coreaceate, with narrow carina.

Elytron ( Fig. 17 View FIGURES 15–26 ) with disk in frontal view sub-moderately convex, in lateral view flattened in anterior half. Shape of elytra distinctly elongated, about two times longer than wide, with lateral margin indistinctly convex in anterior two thirds, indistinctly diverging, maximum width slightly posterior middle. Humerus rounded off. Base distinctly retracted. Reflexed lateral margin slightly crenulate in anterior half. Row of setigerous punctures in the lateral channel of equal distance. Scutellar striole distinct; setigerous tubercle at base of first stria distinct, with tubercle at base of third interval extraordinary small, nearly invisible, basal declivity perpendicularly falling to pedunculus, with isodiametric reticulation. Striae moderately deep, nearly impunctate, one to four free at base, five and six joining at humerus, one and two, three and four, and five and six joining at apex. Intervals somewhat flattened but still slightly convex, interval three with four setigerous punctures joining third stria, interval five joining lateral margin at humerus as short carina, interval seven and eight not carinate, seventh running to apex as obtuse convexity, convexity of eighth ending before apex. Surface of interval one to seven smooth, glossy, interval eight widened, with distinct and clear isodiametric reticulation.

Hind wing fully developed.

Lower surface. Proepisternum distinctly isodiametrically reticulated. Sternite of abdomen with isodiametric reticulation. Last visible sternite with the two marginal setigerous punctures widely separated, with somewhat widened projection at margin (in both sexes).

Legs. Protibia slender, with longitudinal reticulation, with moderately wide sulcus dorsally, with three slender spines and obtuse tooth basally, basal tarsomere slender, slightly convex, and flattened at base, carinate laterally, with acute tubercle and two setae at middle of tarsomere. Profemur with distinct transverse nearly parallel wrinkles dorsally and ventrally. Intermediate tibia with eight tubercles at the lateral side, with slender spur near apex, all setae furnished. Tarsomeres of front and intermediate leg widened.

Male genitalia ( Fig. 86 View FIGURES 85–96 ). Median lobe relatively short, moderately arcuate at middle, straight to apex. In lateral view moderately robust, widely acuminated. Parameres regularly convex at middle, with small and elongated apophyses, distorted at base, hyaline apically, asetose. Female gonocoxites and epipleurite ( Fig. 112 View FIGURES 110–128 ). Basal gonocoxite crescent-shaped, with two long setae, apical gonocoxite relatively stout, nearly straight, with long seta at basal third, with two very long setae apically. Epipleurite lappet-like, basally with two setae close together.

Variation. On the frons of the head, the numbers of punctures postero-laterally vary. On the disk of the pronotum, the punctures vary in number.

Distribution. Known from Brunei on the island of Borneo .

Diagnosis. A medium sized fuscous to ferruginous species with cordate pronotum and interval eight of the elytron distinctly reticulated. The other three species with conspicuously elongated flange of the pronotum, and with missing carinae on the intervals, C. geiseri sp. nov., C. subdepressa Kult , and C. depressiforma sp. nov. show a different shape of the pronotum which is in all three cases distinctly wider than long and conspicuously cordate whereas in C. gracilicollis sp. nov. it is distinctly longer than wide and more elongate than cordate. In addition, in C. gracilicollis sp. nov. the base of the pronotum is conspicuously retracted.

Etymology. The name refers to the slender pronotum (Latin: gracilis = slender; collum = pronotum).