Diochus pulchellus , Cameron 1918
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 pulchellus

description: 11. Diochus pulchellus Cameron, 1918
(Figs 1K; 11-1; 11-2)
Diochus pulchellus Cameron, 1918: 84 (Type locality: Singapore: Sembawang); Cameron, 1921: 404 (Singapore); Scheerpeltz, 1933: 1324 (catalog); Herman, 2001: 2448 (catalog); Rougemont, 2001: 62 (Hongkong); Smetana, 2004 (Palaearctic catalog; Hongkong); Löbl & Löbl, 2015: 1007 (Palaearctic catalog; Hongkong); Zhou & Zhou, 2016: 26 (redescription, photo and line-drawing plates).
Material examined. SINGAPORE: Holotype: male, “Holo-, Type” (printed and handwritten black, rounded label with red borders), “TYPE” (red, handwritten), “HOLOTYPE, Diochus, pulchellus, Cameron, 1918, det. R.G. Booth 2013”/ “Sembawang, Singapore., Dr. Cameron.” (black, printed), “Debris” (black, printed), “ M.Cameron., Bequest., B.M.1955–147.”, “HOLOTYPE, Diochus pulchellus Cameron, 1918, det. R.G. Booth 2013” (NHMUK).
Note. The holotype is partly damaged and was dissected and partly disarticulated before the current study. The aedeagus is partly deformed and embedded in the middle (Fig 11-2G). Due to poor condition of the specimen we decided not to remount and clean again the specimen and the aedeagus.
Additional material examined. INDONESIA: Panaitan Island, 2 males, 1 females: Prinsen Eil., 20.i.1922, damm (SDEI, NHMUK); Bali: 1 female, Sanur, at light, II.87, Rougemont (JJRC); Lombok: 1 female (elytra missing), Segaot, 13: VI: 1984, Rougemont (GROG); CHINA: Hong Kong: 1 male, 23.XI.1996, Mai Po, Winkler extraction, G. de Rougemont (GROG); 1 female, #25 of Hong Kong, Mai Po Nature Reserve, 21.vi.-5.vii.2014, leg.: C. Barthelemy, Malaise Trap (GROG). LAOS: 1 male, Viang Chan prov., Ban Pa Kho resort, 50 km NE Vientiane, 90m, 9.-14.VI.2007, M. ŠTRBA leg.” (SMNS).
Diagnosis. D. pulchellus is a small species with bicolored elytra and a complex spermatheca divided in two tubes: a shorter lateral tube and a main tube with many bends and basally connected with a sclerotized plate (Figs 11-2M–Q). These characters and also the shape of the aedeagus and missing or incomplete basal transverse carina of the male sternite VIII can be used to separate it easily from all other species.
Redescription. A detailed redescription of the species based on the holotype was published by Zhou & Zhou (2016). As some details are not visible in the schematic pictures of the male sternite VIII (incomplete, medially interrupted basal transverse carina of male sternite VIII) and the aedeagus (paired middle sclerite) published by the authors, we made photographs of these characters of the holotype (Fig 11-1L–M, Fig 11-2G–L).
Variability. D. pulchellus shows great variability in external characters such as shape of head and pronotum and also coloration of the forebody (e.g. color of the head varies from black to dark reddish brown and the head varies from slightly to markedly elongate: Figs 11-1A, D, N, O). The basal transverse carina of male sternite VIII is interrupted in the middle in the holotype (Fig. 11-2A–B), but completely missing in all other specimens (Figs 11- 1H; Figs 11-2C–F). Most of the specimens (including the holotype) possess a specific bilobate sclerite in aedeagus (Figs 11-2G, J–K; detail in Fig 11-2L). The bilobate sclerite is not always visible (Fig 11-1M; 11-2H), but it may be covered by other darker sclerites.
Distribution. Singapore; Indonesia (Painatan Island, Bali, Lombok); China (Hong Kong), Laos.
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 473-474, DOI: 10.11646/zootaxa.5632.3.2, http://zenodo.org/record/15372327