Diochus ochraceus Cameron, 1926

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 : 535-537

10. Diochus ochraceus Cameron, 1926

( Figs 1L ; 11 )

Diochus ochraceus Cameron, 1926: 347 (Type locality: Siwaliks, Mothronwala); Cameron, 1932: 47 (characters; India); Scheerpeltz, 1933: 1324 (catalog).

Type material examined. INDIA: Holotype: female, “Type” (printed black, rounded label with red borders), “Dehra Dun, Dr. Cameron, 19/12/1920 / Mothronwalla, Shingle” (printed and Cameronʼs handwriting) // “ Diochus ochraceus Cam. TYPE” (black and red, Cameronʼs handwriting) // M. Cameron. Bequest. B.M.1955-147.“ ( NHMUK).

Note. We examined the unique female type from the Cameronʼs collection ( NHMUK), which we considered as a holotype. The specimen was remounted, glued on a new card plate, spermatheca and last abdominal segments were embedded in Euparal on a plastic strip placed at the same pin as the specimens .

Measurements. BL = 3.18 mm, FL = 1.49 mm, HL = 0.44 mm, HW = 0.37 mm, EyL = 0.10 mm, TL = 0.25 mm, ANL = 0.86 mm, ANT1 = 0.14 mm, ANT2 = 0.07 mm, ANT3 = 0.08 mm, ANT4 = 0.05 mm, ANT 11 = 0.12 mm, PL = 0.55 mm, PW = 0.46 mm, EL = 0.52 mm, EW = 0.58 mm, SL = 0.39 mm.

Description. Body long, narrowed anteriorly and posteriorly, small-sized. Body reddish-ochraceous, abdomen light reddish brown, abdominal segment VII darker brown, abdominal intersegmental membrane lighter. Legs, antennae, maxillary and labial palpi yellowish.

Head ( Fig 11B ). Relatively short, rounded trapezoid in shape, 1.19 times as long as wide. Tempora straight, markedly widened posteriad, posterior angles rounded. Dorsal surface moderately shiny, bearing distinct and transverse microstriae and transverse mesh, 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, slightly protruding laterad, longitudinal diameter shorter than half the length of tempora (eye: tempora = 0.38). 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 (0.07 mm).

Antennae ( Fig 11C ). Scape rod-shaped, markedly thickened apically, distinctly shorter than two subsequent antennomeres combined; antennomere 2 slightly elongate, antennomere 3 slightly longer than 2; antennomere 4 about as long as wide, antennomere 4 to 10 gradually shortened, antennomere 10 very transverse, about 1.6 as wide as long; antennomere 11 distinctly longer than 10.

Mouthparts ( Fig 11B ). 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.

Neck ( Fig 11B ). Cylindrical, shiny, without microsculpture, width 0.13 mm, shorter than 1/3 of head width. Dorsal surface with distinct groove.

Prothorax ( Fig 11B ). Pronotum distinctly elongate (PL to PW ratio 1.20), longer and wider than head. Anterior region near anterior angles deflexed, lateral margins almost parallel, only slightly widened posteriad to basal 1/4 (widest at 1/4), then slightly convergent backwards, anterior and posterior angles broadly rounded. Dorsal surface glossy, with scattered 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, 10–12 punctures scattered near each margin (including anterior, lateral and posterior margins).

Pterothorax ( Fig 11B ). Mesoscutellum triangular, surface shiny, bearing distinct slightly transverse mesh, but without any punctures.

Elytra ( Fig 11B ). Elytra transverse (EL to EW ratio 0.89), distinctly 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 6 punctures in median, also with 4−5 rows of punctures on deflexed portion.

Legs ( Fig 11A ). 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 ( Fig 11A ). 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. Posterior margin of tergite VII with distinct palisade fringe.

Male. Unknown.

Female ( Fig 11D ). Head without elevation between eyes. Sternite VIII with posterior margin rounded. Tube of spermatheca long and sclerotized, with two bends at basal part.

Distribution. India.

Diagnosis. This species is small-sized, reddish-ochraceous in body color, with nearly triangle head and extremely short antennae, which shows great difference from its congeners.

Figures

FIGURE 1. Habitus of Diochus species from Bhutan, India, Nepal, Myanmar, Pakistan and Thailand in dorsal view: A. D. guizhouensis Shuai, Nozaki & Tang, 2021; B. D. setatus sp. nov.; C. D. setifer sp. nov.; D. D. emarginatus sp. nov.; E. D. cameroni sp. nov.; F. D. ceylonicus sp. nov., 1929; G. D. conicollis (Motschulsky, 1858); H. D. punctipennis (Motschulsky, 1858); I. D. keralanus sp. nov.; J. D. antennatus (Motschulsky, 1858); K. D. bicoloripennis Coiffait, 1981; L. D. ochraceus Cameron, 1926 (Scale bar: 0.5 mm; photos of six new species based on the holotype respectively).

FIGURE 11. Diochus ochraceus Cameron, 1926:A. habitus, dorsal view; B. forebody, dorsal view; C. antenna; D. spermatheca; E. labels. (Scale bars: A, B = 0.5 mm, C, D = 0.1 mm).