Diochus lombokensis Huang, Janák & Zhou, 2025

3. Diochus lombokensis Huang, Janák & Zhou , sp. nov.

( Figs 1I View FIGURE 1 ; 4-1; 4-2)

Type locality. Indonesia: Lombok .

Type material. Holotype: male, INDONESIA: LOMBOK: Mt. Rinjiani, Senaro , 400 m, Waterfalls, 5. XI. 1991, I. Löbl ( MHNG) . Paratypes: INDONESIA: LOMBOK: 1 male, same data as holotype ( MHNG) ; Bali: 1 female, Lake Buyan , 1200 m, 8 - 9. XI. 1991, forest, I. Löbl, litter ( MHNG) ; Timor NTT : 1 male, 3 females, 11 km N Soe, 30. 3. 1991, F91856, D. Agosti, everg. for. ( MHNG, JJRC) .

Measurements. BL = 4.00 mm, FL = 1.96 mm, HL = 0.56 mm, HW = 0.42 mm, EyL = 0.15 mm, TL = 0.30 mm, ANL = 1.08 mm, ANT1 = 0.15 mm, ANT2 = 0.10 mm, ANT3 = 0.11 mm, ANT4 = 0.08 mm, ANT 11 = 0.12 mm, PL = 0.72 mm, PW = 0.58 mm, EL = 0.73 mm, EW = 0.78 mm, SL = 0.57 mm.

Description. Body long, narrowed anteriorly and posteriorly, small to medium-sized. Body brown to dark brown, abdominal intersegmental membrane lighter. Legs yellowish brown, tarsi distinctly lighter. Antennae dark brown to light brown, apex of each antennomere lighter. Maxillary and labial palpi yellowish brown.

Head (Fig 4-1A). Rounded rectangle in shape, 1.33 times as long as wide. Tempora straight and parallel, posterior angles rounded. Dorsal surface shiny, bearing distinct and transverse microstriae, also with coarse and sparse punctures. Head with 5−7 irregular punctures scattered around each eye and numerous smaller punctures on deflexed portion of temple and near posterior margin. Each side of head with characteristic punctures: one frontal puncture on frontal region, two anterolateral punctures near antennal insertion, three lateral punctures near dorsal margin of eye, with temporal puncture and occipital puncture near basal margin; disc surface bearing two additional paired punctures in middle area. Frontal furrows and anteocular furrows absent. Eye medium-sized, distinctly protruding laterad, longitudinal diameter about half the length of tempora (eye: tempora = 0.51). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.13 mm) distinctly longer than distance from antenna to eye (0.07 mm). Ventral surface with scattered punctures, interspaces between them as large as about 4 puncture diameters. Gular sutures deep, confluent at basal 1/6, then extended to base.

Antennae (Fig 4-1B). Scape rod-shaped, slightly thickened apically, distinctly shorter than two subsequent antennomeres combined; antennomere 2 elongate; antennomere 3 slightly longer than 2; length of antennomere 4 about 1.5 times of width, antennomere 4 to 10 gradually shortened, antennomere 4 observably longer than 10; antennomere 11 distinctly longer than 10.

Mouthparts (Fig 4-1A). Labrum oval-shaped, lateral margins rounded, widest at basal 1/2; anterior margin narrow, about 1/5 of width at the widest point. Mandibles (Fig 4-1D) falciform, left one with three small teeth on inner margin, whereas right one with two.

Neck (Fig 4-1A). Cylindrical, shiny, only bearing shallow microsculpture, width 0.13 mm, shorter than 1/3 of head width. Dorsal surface with distinct groove; ventral surface with gular sutures forming obvious triangular region, with deep transverse median furrow.

Prothorax (Fig 4-1A). Pronotum elongate (PL to PW ratio 1.23), distinctly longer and wider than head. Anterior region near anterior angles slightly deflexed, lateral margins widened posteriad to basal 1/4 (widest at 1/4), then convergent backwards, anterior and posterior angles broadly rounded. Dorsal surface glossy, extensively with micropunctures, but without any microsculpture. Each side of longitudinal midline with one row of punctures composed of 3 large punctures and 2 additional punctures outside of puncture row, 13–15 punctures scattered near each margin (including anterior, lateral and posterior margins). Prosternum bearing an observable transverse ridge between basisternum and furcasternum, angularly backwards.

Pterothorax (Fig 4-1A). Mesoscutellum triangular and small, surface shiny, bearing distinct microstriae, but without any punctures. Transverse ridge on mesoventrite wave shaped; paired oblique furrows short but deep; carina limiting mesocoxal cavity slightly arcuate. Discrimen region on metaventrite normally elevated.

Elytra (Fig 4-1A). Elytra slightly transverse (EL to EW ratio 0.95), longer and wider than pronotum. Humeri well developed, lateral margins divergent posteriorly, posterior margin not rounded, but obliquely truncate. Dorsal surface shiny, flattened, without microsculpture; each elytron with row of 5 punctures along suture, row of 5 punctures on disc, also with 4−5 rows of punctures on deflexed portion.

Legs (Fig 4-1C). First four segments of protarsi heart-shaped, moderately dilated, and those of meso- and metatarsi slender. Last segment of protarsi slightly shorter than 2−4 together, that of meso-, meta- slightly shorter than the length of each 2−3.

Abdomen. Broadest at segment V. Tergites III–VII covered with dense and obvious transverse microstriae; each tergite with dense brown pubescence, also with row of darker and coarser setae at posterior margin of III–VI. Tergites III–VII with a basal impression near anterior margin, respectively, each one only possessing one basal transverse carina; all abdominal tergites with surface shiny, bearing polygonal microsculpture, with dense punctures. Posterior margin of tergite VII with distinct palisade fringe. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male (Figs 4-1E–J; 4-2A–E). Head with small round elevation between eyes. Posterior margin of sternite VIII not emarginate medially, but nearly straight, with several short setae, each side truncate (Figs 4-1E; 4-2B). Posterior margin of tergite VIII arcuate (Figs 4-1F; 4-2C). Tergite IX (Figs 4-1H; 4-2D) symmetrical, connected mediobasally, narrowed apically. Sternite IX (Figs 4-1G; 4-2E) symmetrical, widest at 1/2 to 1/3; basal margin straight, apical margin normally emarginate; width of apical margin about 1.5 times of basal margin. Tergite X (Figs 4-1H; 4-2D) symmetrical, triangular. Aedeagus (Figs 4-1I−J; 4-2A) symmetrical, medium-sized, ca. 0.60 mm long, normally sclerotized. Parameres symmetrical, extremely thick and short, reaching to about half of median lobe. Internal structures sclerotized, paired L-shaped sclerites on upper middle, in black color; two paired strips shaped sclerites located on both sides, in black color; 3 sclerites in middle: paired rectangular sclerites in brown color, one Y-shaped sclerite in brown to black color. Sperm pump coiled, thinned toward apex.

Female (Figs 4-2F−I). Head without elevation between eyes. Sternite VIII (Fig 4-2F) with posterior margin rounded. Tergite IX bearing numerous setae, elongate and sharply pointed apically. Sternite IX (Fig 4-2H) symmetrical, with deep concave margin in middle. Tergite X broad, basal margin curved. Sternite X (Fig 4-2G) slender and rhomboidal, with numerous setae in lower half. Tube of spermatheca sclerotized, long and coiled (Fig 4-2I).

Distribution. Indonesia.

Diagnosis. This species is related to the Australian species D. octavii Fauvel, 1877 and D. pubiventris Lea, 1929 based on the similar aedeagal structure, also with similar shape of male sternite VIII: medial part of posterior margin straight and with short setae. Compared to D. octavii , this new species has distinctly lighter coloration, posterior margin of male sternite VIII with medial straight part distinctly wider, and male aedeagus with parameres thicker and shorter. Compared to D. pubiventris , male sternite VIII of this new species is with posterior angles truncate, not rounded, and basal margin of sternite IX is wider.

Etymology. The species epithet is derived from the name of type locality, Lombok ( Indonesia).