1. Diochus cameroni Huang, Janák & Zhou, sp. nov.

(Figs 1E; 2-1; 2-2; 2-3)

Type locality. India: Meghalaya: Khasi Hills .

Type material. Holotype: male, INDIA: Meghalaya: Khasi Hills, Nongpoh, 700 m, 5. XI. 78, Besuchet-Löbl (MHNG) . Paratypes: INDIA: Meghalaya: 1 male, 2 females, same data as holotype (MHNG); 1 male, Khasi Hills, Mawsynram-Balat, 1000 m, 27. X. 78, Besuchet-Löbl (MHNG) ; 2 females, Khasi Hills, Dawki, 500−800 m, 29. X. 78, Besuchet-Löbl (MHNG) ; 1 male, 5 females, Garo Hills, Tura, 700−900 m, 1. XI. 78, Besuchet-Löbl (MHNG) ; 1 female, Garo Hills, Rongrengiri, 400 m, 3. XI. 78, Besuchet-Löbl (MHNG) ; W. Bengal: 1 male, Darjeeling distr., Mahanadi, 1200 m, 6. X. 78, Besuchet-Löbl (MHNG); 3 females, Darjeeling distr. Kalimpong, 1300 m, 11. X. 78, Besuchet-Löbl (MHNG) ; Uttar Pr.: 1 male, Garhwal: below Mussoorie, 1700 m, 19. X. 79 15, Löbl (MHNG) ; Garhwal (UP) : 40 males, 49 female, 20 km au Sud de Chamba, 1150 m, 20. X. 79, I. Löbl (MHNG) ; 1 female, Lachiwala 13 km est de Dehra Dun, 650 m, 17. X. 79, I. Löbl (MHNG) ; 15 males, 17 females, Route pour Mussoorie, 1300 m, 18. X. 79, I. Löbl (MHNG) ; 1 male, Mussoorie, 1700 m, 10. X. 79, I. Löbl (MHNG) ; 2 males, 3 females, Mussoorie, 1700 m, 19. X. 79, I. Löbl (MHNG) ; 5 males, 8 females, près de Chamoli à 16 km de Karnaprayag, 900 m, 26. X. 79, I. Löbl (MHNG) ; 1 male, 2 females, 16 km de Srinagar, 550 m, 29. X. 79, I. Löbl (MHNG) ; 1 female, 22 km N. de Rishikesh, 450 m, 30. X. 79, I. Löbl (MHNG); Kumaon (UP) : 23 males, 14 females, Kathgodam près Haldwani, 600 m, 6.X. 79, I. Löbl (MHNG) ; 3 females, Rangarh, 2000 m, 9. X. 79, I. Löbl (MHNG) ; 1 male, 2 females, Garjia à 10 km de Ramnagor, 450 m, 15. X. 79, I. Löbl (MHNG) ; “ Schaum ”, “coll. Kraatz ”, “PARATYP”, “ PARALECTOTYPUS Diochus major Kraatz, J. Janák des. 2022” (SDEI) ; 1 male, Dehra Dun, Dr Cameron (MHNG) ; 1 male, 4 females, Nakraunda, Siwaliks, Dr. Cameron, 28-I-1923 (NHMUK, JJRC) ; 1 female, Nakraunda, Siwaliks, Dr. Cameron, 8-X-1922 (NHMUK) ; 3 females, Mossy Falls, Mussoorie, Dr. Cameron, 6.3.21 (NHMUK, JJRC) ; 1 female, Fagu, 8000ʼ, Simla Hills, Dr. Cameron, 8.IX.1921 (NHMUK) ; 2 females, Dehra Dun, Dr.Cameron, 24/12 1920 (NHMUK) ; 1 female, Dehra Dun, Dr.Cameron, 30.9.1922 (NHMUK) ; 1 female, Lachiwala, Siwaliks, Dr. Cameron, 8.4.1923 (NHMUK) ; 1 female, Aglar R., Tehri Garhwal, Dr. Cameron, 28.III.1921 (NHMUK) ; 1 female, Arni Gad, Mussoorie, Dr. Cameron, 17.IV.21 (NHMUK) ; 1 female, Kaligad, Dehra Dun, 10.VII.21 (NHMUK) ; 1 male, Haldwani Dist., Kumaon, India, H.G.C. (NHMUK) ; 1 male, 1 female, N. India, JMW-1231-N, Robers Cave, Nr. Dehra Dun, in moss, 18-II-76. BM 1977-117 (NHMUK, JJRC) ; 1 female, Mossy Falls, Mussoorie, Dr. Cameron, 6.2.26 (NHMUK) ; 1 male: W. Almora Divn, Kumaon, UP, Feby. 1918, H. G.C. (JJRC); 1 female, W. Almora Divn, Kumaon, UP, June 1917, H. G.C. (NHMUK) ; 1 female, Theog 7600ʼ, Simla Hills, Dr. Cameron IX.1921 (NHMUK) ; 1 female, Nakraunda, Siwaliks, Dr. Cameron, 28-I-1923 (NHMUK) ; 10 males, 7 females, Haldwani Dist., Kumaon, India, H.G.C. (NHMUK, JJRC) ; 1 male, Kumaon, W Almora, India, H.G.C. (NHMUK) ; 1 male, 3 females, Mossy Falls, Mussoorie, Dr. Cameron, 6.3.21 (NHMUK, JJRC) ; 1 male, Bangar, 6000, Chakrata, U.P., Dr. Cameron, 1.V.21 (NHMUK) ; 1 female, Mohan Rau, Siwaliks, U.P., Dr Cameron, 3.10.21 (NHMUK) ; 2 male, Nakraunda, Siwaliks, Dr. Cameron, 28-I-1923 (NHMUK) ; 1 male, Ranikhet, Kumaon, India, H.G.C. (NHMUK) ; 1 female, Kheri Rau, Siwaliks, Dr. M. Cameron, 23.X.1921 (NHMUK) ; 1 male, Uttaranchal, Rokcheli [str.], Bageshwar Distr., 14.XI.2006, leg. M.A. Jäch, 29° 54ʼ 44ʼʼ N/79° 50ʼ 01ʼʼ at Gouina ca. 13km N Bageshwar, 1020 m a.s.l. (NHMW) ; 1, female, Uttaranchal state, Nainital env., 1900–2100 m, 19.- 21.6.2003, leg. Z. Kejval & M. Trýzna (NHMW) ; 1 male, 1 female, H.P. Nagar VI: 1981, Rougemont (GROC); 1 male, India: H.P. Simla VI: 1981, Rougemont (GROC) ; 4 males, 1 female, Nepal Janga Pass, XI 1987, 1200– 700 m, P. Morvan (GROC) ; 1 male, 1 female, Uttarakhand, 14 km E Uttarkashi, 30°45ʼN, 78°34ʼE, 1450 m, 10.-12.IV.2012, leg. A. Shavrin (VAHC) ; ANDAMAN ISLANDS: 3 females, S. Andaman, Port Blair, Mt Harriet, 2.1.79, Osella (MCVR) ; 1 female, S. Andaman, Port Blair, Mt Harriet, 3.1.79, Osella (MCVR) ; LAOS: 2 females, Houa Phan prov., Phou Pane Mt., 20°13ʼN, 104°00ʼE, 1480-1510 m, 22.IV.-14.V.2008, V. Kubáň (VAHC) . BHUTAN: 1 male, Bhutan, Phuntsholing X.1980, de Rougemont (GROC) . NEPAL: KOSI: 1 male, 1 female, Val. Arun ss/ Num, 1100 m, 21. IV. 84, Löbl-Smetana (MHNG) ; 1 male, 1 female, Himalaya, Dhawalagiri 2004, Baglung Lekh, Myagdi Khola Valley, 5 km north Babichaure, 22.05.04, leg. A. Kleeberg (AKBG) ; 1 male, Barahbise geg., Ting-Sang-La, lg. H. Franz (NHMW) ; 1 female, Dangsur 900 m, P. Morvan (GROC) ; 1 male, 1 female, Darame V. 1000m, IV.77, Morvan (GROC, JJRC); 1 male, Chapuri 16. III. 1979, de Rougemont (GROC) ; 1 male, 1 female, Dumahan IV.1984, Rougemont collection (GROC, JJRC) . PAKISTAN: Swat, 3 males, Col de Karakar, 1300 m; 19. V. 1983, Besuchet-Löbl (MHNG) . Holotype with an identification label: “ HOLOTYPUS Diochus cameroni sp. nov. Huang, Janák & Zhou det. 2024”. Paratypes with identification labels: “ PARATYPUS Diochus cameroni sp. nov. Huang, Janák & Zhou det. 2024”, “ PARATYPUS Diochus cameroni sp. nov. Janák det. 2017” or “ PARATYPUS Diochus cameroni sp. nov. Janák det. 2022”.

Measurements. BL = 5.62 mm, FL = 2.47 mm, HL = 0.67 mm, HW = 0.51 mm, EyL = 0.15 mm, TL = 0.38 mm, ANL = 1.54 mm, ANT1 = 0.26 mm, ANT2 = 0.15 mm, ANT3 = 0.20 mm, ANT4 = 0.13 mm, ANT 11 = 0.15 mm, PL = 0.94 mm, PW = 0.74 mm, EL = 0.88 mm, EW = 1.00 mm, SL = 0.64 mm.

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

Head (Figs 2-1A, I). Oblong in shape, 1.30 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 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 shorter than half the length of tempora (eye: tempora = 0.41). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.10 mm) distinctly longer than distance from antenna to eye (0.06 mm). Ventral surface with scattered punctures, interspaces between them about 4 puncture diameters. Gular sutures deep, confluent at basal 1/4.

Antennae (Fig 2-1B). Scape rod-shaped, slightly thickened apically, distinctly shorter than two subsequent antennomeres combined; antennomere 2 slightly elongate, antennomere 3 distinctly longer than 2; 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 (Figs 2-1A, I). Labrum nearly hexagonal, lateral margin straight, widest at basal 1/3 to 1/2; width of anterior margin is about 1/2 the width at the widest point. Mandibles (Fig 2-1D) falciform, left one with three small teeth on inner margin, whereas right one with two.

Neck (Figs 2-1A, I). 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 (Figs 2-1A, I). Pronotum distinctly elongate (PL to PW ratio 1.26), 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 (Figs 2-1A, I). 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 (Figs 2-1A, I). Elytra transverse (EL to EW ratio 0.88), 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, a row of 5 punctures and a row of 4 punctures on disc, also with 4−5 rows of punctures on deflexed portion.

Legs (Fig 2-1C). First four segments of protarsi heart-shaped, moderately dilated, and those of meso- and metatarsi slender. Last segment of protarsi distinctly longer than 2−4 together, that of meso-, meta- nearly equal to 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 2-1E–H, J; 2-2A–D; 2-3A–E). Head with a small round elevation between eyes. Posterior margin of sternite VIII emarginate medially (Figs 2-1E, J; 2-3B). Posterior margin of tergite VIII arcuate (Figs 2-1F; 2-3C). Tergite IX (Figs 2-1H; 2-3D) symmetrical, connected mediobasally, narrowed apically. Sternite IX (Figs 2-1G; 2- 3E) symmetrical, widest near basal 1/2 to 1/3; basal margin not straight, but sharp at angles, apical margin normally emarginate; width of apical margin shorter than 1/2 of basal margin. Tergite X (Figs 2-1H; 2-3D) symmetrical, triangular. Aedeagus (Figs 2-2 A−D; 2-3A) symmetrical, medium-sized, ca. 0.67 mm long, normally sclerotized. Parameres symmetrical, thin and long, reaching to apical fifth to eighth of median lobe. Internal structures sclerotized, composed of four parts: paired oval sclerites and paired rod-shaped sclerites at periphery, black color; 3 sclerites in the middle: pair rectangular sclerites in black color, a Y-shaped sclerite in brown color. Sperm pump coiled, thinned toward apex.

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

Distribution. India, Nepal, Pakistan.

Diagnosis. The species is externally very similar to D. emarginatus sp. nov., but has more elongated pronotum and elevation between eyes rounded. It differs from other related species by the shape of male sternite VIII with rounded triangular emargination and the tube of the spermatheca with three bends.

Etymology. The species is named in honor of Malcolm Cameron (1873–1954), a famous specialist in Staphylinidae, who collected part of the type specimens.