Diochus ceylonicus Huang, Janak & Zhou 2024, sp. nov.
Creators: name: Huang, Tian
name: Janák, Jiří
name: Zhou, Hong-Zhang
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Diochus
Diochus ceylonicus

description: 6. Diochus ceylonicus Huang, Janák & Zhou, sp. nov.
(Figs 1F; 7-1; 7-2)
Type locality. SRI LANKA: Anuradhapura.
Type material. Holotype: male, SRI LANKA: Anuradhapura, W Horn 1899 (SDEI). Paratype: INDIA: Madras: 1 male, Anaimalai H. Près d'Aliyar Dam, 300 m, 17. XI. 1972, Besuchet Löbl Mussard (MHNG). Holotype with an identification label: “ HOLOTYPUS Diochus ceylonicus sp. nov. Huang, Janák & Zhou det. 2024”. Paratype with an identification label: “ PARATYPUS Diochus ceylonicus sp. nov. Huang, Janák & Zhou det. 2024”.
Measurements. BL = 5.42 mm, FL = 2.83 mm, HL = 0.75 mm, HW = 0.53 mm, EyL = 0.21 mm, TL = 0.41, ANL = 1.16 mm, ANT1 = 0.15 mm, ANT2 = 0.10 mm, ANT3 = 0.11 mm, ANT4 = 0.08 mm, ANT 11 = 0.14 mm, PL = 0.96 mm, PW = 0.75 mm, EL = 0.98 mm, EW = 0.98 mm, SL = 0.69 mm.
Description. Body long, narrowed anteriorly and posteriorly, large-sized. Body yellowish brown, abdominal intersegmental membrane lighter. Legs yellow, tarsi distinctly lighter. Antennae brown, apex of each antennomere lighter. Maxillary and labial palpi brown.
Head (Figs 7-1A, E). Oval in shape, 1.43 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 small-sized, distinctly protruding laterad, longitudinal diameter shorter than half the length of tempora (eye: tempora = 0.51). Epistoma not flattened, abruptly oblique, anterior margin slightly emarginate medially. Distance between antennal insertions (0.17 mm) distinctly longer than distance from antenna to eye (0.08 mm). Ventral surface with scattered punctures, interspaces between them about 4 puncture diameters. Gular sutures deep, confluent at basal 1/4, then extended to base.
Antennae (Fig 7-1B). 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 thrice of width, antennomere 4 to 10 gradually shortened, antennomere 4 observably longer than 10; antennomere 11 distinctly longer than 10.
Mouthparts (Figs 7-1A, E). Labrum nearly hexagonal, lateral margin straight, widest at basal 1/3; width of anterior margin is about 1/3 the width at the widest point. Mandibles (Fig 7-1G) falciform, left one with three small teeth on inner margin, whereas right one with two.
Neck (Figs 7-1A, E). Cylindrical, shiny, only bearing shallow microsculpture, width 0.17 mm, shorter than 1/3 of head width. Dorsal surface with distinct groove; ventral surface with gular sutures forming obvious triangular region, transverse median furrow absent.
Prothorax (Figs 7-1A, E). Pronotum yellowish brown, elongate (PL to PW ratio 1.28), 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 (Figs 7-1A, E). Mesoscutellum small and 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 7-1A, E). Elytra yellowish brown, about as long as wide (EL to EW ratio 1.00), 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 6 punctures in median, also with 4−5 rows of punctures on deflexed portion.
Legs (Fig 7-1F). 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 7-1C−D, H–M; 7-2A–E). Head with a small round elevation between eyes. Posterior margin of sternite VIII emarginate medially and shallowly, with almost straight median part (Figs 7-1C, H; 7-2B). Posterior margin of tergite VIII arcuate (Figs 7-1I; 7-2C). Tergite IX (Figs 7-1K; 7-2D) symmetrical, connected mediobasally, narrowed apically. Sternite IX (Figs 7-1J; 7-2E) asymmetrical, widest near basal 1/3 to 1/2; basal margin slightly emarginate, apical margin normally emarginate; width of apical margin about twice the length of basal margin. Tergite X (Figs 7-1K; 7-2D) symmetrical, triangular. Aedeagus (Figs 7-1D, L−M; 7-2A) symmetrical, medium-sized, ca. 0.64 mm long, surface mostly membranous. Parameres symmetrical, short and wide, slightly curved, reaching four tenths of median lobe. Internal structures symmetrical and mostly membranous. Sperm pump coiled, thinned toward apex.
Female. Unknown.
Distribution. Sri Lanka, India.
Diagnosis. According to the narrow and elongate head, elongate aedeagus with short parameres, the species can be easily distinguished from other species.
Etymology. The species epithet is derived from the historical name of Sri Lanka – Ceylon.
description: Published as part of 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, pp. 501-545 in Zootaxa 5538 (6) on pages 523-526, DOI: 10.11646/zootaxa.5538.6.1, http://zenodo.org/record/14240051