Diochus emarginatus Huang, Janák & Zhou, 2024

Huang, Tian, Janák, Jiří & Zhou, Hong-Zhang, 2024, Six new species and a key to 12 species of the genus Diochus Erichson (Coleoptera: Staphylinidae, Staphylininae, Diochini) from India, Nepal and Pakistan, Zootaxa 5538 (6), pp. 501-545 : 509-512

publication ID	https://doi.org/ 10.11646/zootaxa.5538.6.1
publication LSID	lsid:zoobank.org:pub:B749F7E3-9AF2-460C-90C4-41C466A6AF5A
DOI	https://doi.org/10.5281/zenodo.14248197
persistent identifier	https://treatment.plazi.org/id/03E287E6-DF19-FFA1-FF1F-FDB8E0AFA13D
treatment provided by	Plazi
scientific name	Diochus emarginatus Huang, Janák & Zhou
status	sp. nov.

Treatment

2. Diochus emarginatus Huang, Janák & Zhou , sp. nov.

( Figs 1D View FIGURE 1 ; 3-1; 3-2 View FIGURE 2-3 )

Type locality. India: Garhwal ( UP).

Type material. Holotype: male, INDIA: Garhwal (UP): 20 km au Sud de Chamba, 1150 m, 20. X. 79, I. Löbl ( MHNG) . Paratypes: INDIA: Garhwal (UP): 3 males, 1 female, same data as holotype ( MHNG, JJRC) ; 2 males, 9 females, Route pour Mussoorie , 1300 m, 18. X. 79, I. Löbl ( MHNG, JJRC) ; 4 males, 2 females, 4 km au Sud de Bhatwari, 1400 m, 23. X. 79, I. Löbl ( MHNG, JJRC) ; 3 males, 5 females, au-dessous de Bhatwari , 1500 m, 24. X. 79, I. Löbl ( MHNG, JJRC) ; Kumaon (UP): 1 male, 3 females, entre Bhim Tah et Sat Tal , 1500 m, 7. X. 79, I. Löbl ( MHNG) ; W. Bengal: 3 females, Darjeeling distr. Mahanadi , 1200 m, 6. X. 78, Besuchet-Löbl ( MHNG) ; 1 male, 4 females, Darjeeling distr. Mahanadi , 1200 m, 19. X. 78, Besuchet-Löbl ( MHNG) ; 1 male, Darjeeling distr. Kalimpong , 1300 m, 11. X. 78, Besuchet-Löbl ( MHNG) . NEPAL: Kosi: 2 females, Val. Arun ss/Num , 1050m, 20. IV. 84, Löbl-Smetana ( MHNG) ; 3 males, 4 females, Val. Arun ss/Num , 1100 m, 21. IV. 84, Löbl-Smetana ( MHNG) ; 1 male, Val. Arun ss/Num , 1050m, 22. IV. 84, Löbl-Smetana ( MHNG) ; Prov. Bagmati: 1 female, 4 km S Tarang Marang, 900 m, 28. IV. 81, Löbl & Smetana ( MHNG) . THAILAND: Chiang Mai: 1 male, Doi Suthep , 1450 m, 4. XI. 1985, Burckhardt-Löbl ( MHNG) . Holotype with an identification label: “ HOLOTYPUS Diochus emarginatus sp. nov. Huang, Janák & Zhou det. 2024”. Paratypes with identification labels: “ PARATYPUS Diochus emarginatus sp. nov. Huang, Janák & Zhou det. 2024”

Measurements. BL = 5.90 mm, FL = 2.39 mm, HL = 0.62 mm, HW = 0.52 mm, EyL = 0.19 mm, TL = 0.37 mm, ANL = 1.32 mm, ANT1 = 0.22 mm, ANT2 = 0.12 mm, ANT3 = 0.13 mm, ANT4 = 0.10 mm, ANT 11 = 0.13 mm, PL = 0.90 mm, PW = 0.73 mm, EL = 0.87 mm, EW = 1.00 mm, SL = 0.64 mm.

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

Head ( Fig 3-1A View FIGURE 2-3 ). Oval shaped, 1.19 times as long as wide. Tempora distinctly widened backwards, 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 tempus and near posterior margin. Each side of cranium 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 = 0.50). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.12 mm) distinctly longer than distance from antenna to eye (0.09 mm). Ventral surface with scattered punctures, interspaces between them about 4 puncture diameters. Gular sutures deep, gradually convergent, but not confluent, then divergent to neck region.

Antennae ( Fig 3-1B View FIGURE 2-3 ). Scape rod-shaped, slightly thickened apically, distinctly shorter than two subsequent antennomeres combined; antennomere 2 slightly 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 3-1A View FIGURE 2-3 ). Labrum oval-shaped, lateral margin rounded, widest at basal 1/3 to 1/2; width of anterior margin is about 1/2 the width at the widest point. Mandibles ( Fig 3-1D View FIGURE 2-3 ) falciform, left one with three teeth, right one with two teeth.

Neck ( Fig 3-1A View FIGURE 2-3 ). Cylindrical, shiny, only bearing shallow microsculpture, width 0.18 mm, about 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 3-1A View FIGURE 2-3 ). Pronotum dark brown, elongate (PL to PW ratio 1.24), distinctly longer and wider than head. Anterior region near anterior angles deflexed, lateral margins widened posteriad to basal 1/3 (widest at 1/3), 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 3-1A View FIGURE 2-3 ). Mesoscutellum triangular, surface shiny, bearing distinct microstriae, but without any punctures. Transverse ridge on mesoventrite wave shaped; the paired oblique furrows short but deep; the carina delimiting mesocoxal cavity slightly arcuate. Discrimen region on metaventrite normally elevated.

Elytra ( Fig 3-1A View FIGURE 2-3 ). Elytra brown, slightly transverse (EL to EW ratio 0.87), distinctly 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 3-1C View FIGURE 2-3 ). First four segments of protarsi heart-shaped, moderately dilated, and those of meso- and metatarsi slender. Last segment of protarsi slightly longer 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 yellow 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 3-1E–J; 3-2A–E View FIGURE 2-3 ). Head with a small elongated elevation between eyes. Posterior margin of sternite VIII emarginate medially, also emarginate on both sides, with fascicular setae ( Figs 3-1E; 3-2B View FIGURE 2-3 ). Posterior margin of tergite VIII arcuate ( Figs 3-1F; 3-2C View FIGURE 2-3 ). Tergite IX ( Figs 3-1H; 3-2D View FIGURE 2-3 ) symmetrical, connected mediobasally, narrowed apically. Sternite IX ( Figs 3-1G; 3-2E View FIGURE 2-3 ) asymmetrical, widest near basal 1/2 to 1/3; basal margin straight, apical margin normally emarginate; width of apical margin distinctly shorter than basal margin. Tergite X ( Figs 3-1H; 3- 2D View FIGURE 2-3 ) symmetrical, triangular. Aedeagus ( Figs 3-1 View FIGURE 2-3 I−J; 3-2A) symmetrical, large-sized, ca. 0.83 mm long, normally sclerotized. Parameres symmetrical, thin and long, reaching to apical fifth of median lobe. Internal structures sclerotized, paired oval sclerites and paired strips shaped sclerites on both sides, black color; paired S-shaped sclerites in the middle, black color, single sclerite in black color. Sperm pump coiled, thinned toward apex.

Female ( Figs 3-2F–I View FIGURE 2-3 ). Head without elevation between eyes. Sternite VIII ( Fig 3-2F View FIGURE 2-3 ) with posterior margin rounded. Tergite IX bearing numerous setae, elongate and sharply pointed apically. Sternite IX ( Fig 3-2H View FIGURE 2-3 ) symmetrical, with deep concaved margin in middle. Tergite X broad, basal margin curved. Sternite X ( Fig 3-2G View FIGURE 2-3 ) slender and rhomboidal, with numerous setae in lower half. Tube of spermatheca long and sclerotized, with three bends ( Fig 3-2I View FIGURE 2-3 ).

Distribution. India, Nepal, Thailand.

Diagnosis. The new species is similar to Diochus guizhouensis and D. cameroni sp. nov. in body size and coloration but can be distinguished by the shape of male sternite VIII, which has an emargination on posterior margin near each lateral corner and possesses fascicular setae.

Etymology. The species epithet is a Latin word, emarginatus , to indicate the special form of the posterior margin of male sternite VIII.