Diochus sulawesiensis Huang, Janak & Zhou 2025, sp. nov.
Creators: name: Huang, Tian
name: Janák, Jiří
name: Zhou, Hong-Zhang
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Diochus
Diochus sulawesiensis

description: 7. Diochus sulawesiensis Huang, Janák & Zhou, sp. nov.
(Figs 1E; 8-1; 8-2)
Type locality. Indonesia: Sulawesi.
Type material. Holotype: male, INDONESIA: Sulawesi: Sel., W of Mamasa, 1000 m, 11. IV. 1991, D. Agosti, F91741 (MHNG).
Measurements. BL = 5.22 mm, FL = 2.38 mm, HL = 0.69 mm, HW = 0.50 mm, EyL = 0.15 mm, TL = 0.40 mm, ANL = 1.40 mm, ANT1 = 0.19 mm, ANT2 = 0.13 mm, ANT3 = 0.14 mm, ANT4 = 0.11 mm, ANT 11 = 0.13 mm, PL = 0.89 mm, PW = 0.68 mm, EL = 0.79 mm, EW = 0.95 mm, SL = 0.60 mm.
Description. Body long, narrowed anteriorly and posteriorly, medium-sized. Body black, abdominal intersegmental membrane lighter. Legs dark brown, tarsi distinctly lighter. Antennae brown to black brown, apex of each antennomere lighter. Maxillary and labial palpi dark brown.
Head (Fig 8-1A). Oblong in shape, 1.38 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 small-sized, not distinctly protruding laterad, longitudinal diameter distinctly shorter than half the length of tempora (eye: tempora = 0.39). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.15 mm) distinctly longer than distance from antenna to eye (0.09 mm). Ventral surface with sparsely scattered punctures, interspaces between them as large as about 4 puncture diameters. Gular sutures deep, confluent near the base.
Antennae (Fig 8-1B). 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 twice of width, antennomere 4 to 10 gradually shortened, antennomere 4 observably longer than 10; antennomere 11 distinctly longer than 10.
Mouthparts (Fig 8-1A). Labrum oval-shaped, lateral margins rounded, widest at basal 1/2; anterior margin about half of width at the widest point. Mandibles (Fig 8-1D) falciform, left one with three small teeth on inner margin, whereas right one with two.
Neck (Fig 8-1A). Cylindrical, shiny, only bearing shallow microsculpture, width 0.15 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 8-1A). Pronotum elongate (PL to PW ratio 1.31), distinctly longer and wider than head.Anterior region near anterior angles 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 8-1A). Mesoscutellum triangular, 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 8-1A). Elytra distinctly transverse (EL to EW ratio 0.89), shorter but 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 8-1C). First four segments of protarsi heart-shaped, slightly 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 8-1E–J; 8-2A–E). Head with an oval elevation between eyes. Sternite VIII with posterior margin emarginate medially, lateral margins strongly narrowed backwards (Figs 8-1E; 8-2B). Posterior margin of tergite VIII arcuate (Figs 8-1F; 8-2C). Tergite IX (Figs 8-1H; 8-2D) symmetrical, connected mediobasally, narrowed apically. Sternite IX (Figs 8-1G; 8-2E) symmetrical, widest at basal 1/3; basal margin moderately emarginate, apical margin deeply emarginate; width of apical margin about 2/3 of basal margin. Tergite X (Figs 8-1H; 8-2D) symmetrical, triangular. Aedeagus (Figs 8-1I−J; 8-2A) symmetrical, medium-sized, ca. 0.59 mm long, normally sclerotized. Parameres symmetrical, thick and short, reaching near half of median lobe. Internal structures sclerotized: paired flag-shaped sclerites and paired rectangular shaped sclerites in middle; an elongated sclerite at bottom. Sperm pump coiled, thinned toward apex.
Female. Unknown.
Distribution. Indonesia (Sulawesi).
Diagnosis. This new species is entirely black in color and male sternite VIII is strongly narrowed to apex, nearly in the form of an inverted triangle, easily distinguishing it from other species.
Etymology. The species epithet is derived from the name of type locality, Sulawesi (Indonesia).
description: Published as part of Huang, Tian, Janák, Jiří & Zhou, Hong-Zhang, 2025, Revision of the genus Diochus Erichson (Coleoptera: Staphylinidae, Staphylininae, Diochini) from Indonesia, Malaysia and Singapore, pp. 441-479 in Zootaxa 5632 (3) on pages 464-467, DOI: 10.11646/zootaxa.5632.3.2, http://zenodo.org/record/15372327