Diochus Erichson 1839
Creators: name: Zhou, Yu-Lingzi
name: Zhou, Hong-Zhang
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Diochus

description: Genus Diochus Erichson, 1839
Erichson, 1839: 300 (species included: nanus); Bernhauer and Schubert, 1914: 319 (world catalog; 21 species); Cameron, 1921: 354, 404 (key to Singapore species; catalog); Blackwelder, 1943: 455 (type species: nanus); Coiffait, 1972: 368 (type species: nanus; key to species of western Palaearctic region); Smetana, 1982: 27 (revision species of North America north of Mexico); Newton et al., 2000: 390 (1 Nearctic species, key); Herman, 2001: 2443 (catalog); Assing, 2003 (revision of the Western Palaearctic species); Smetana, 2004: 624 (Catalogue of Palaearctic Coleoptera); Löbl & Löbl, 2015: 1007 (Palaearctic catalog).
Type species: Diochus nanus Erichson, 1839: 300, fixed by monotypy.
Syn.: Rhegmatocerus Motschulsky, 1858: 657 (species included: conicollis, punctipennis, antennatus); Gemminger and Harold, 1868: 608 (synonym of Diochus); Bernhauer and Schubert, 1914: 319 (synonym of Diochus); Cameron, 1932: 44 (synonym of Diochus); Blackwelder, 1943: 455 (synonym of Diochus; type species: punctipennis); Coiffait, 1972: 368 (synonym of Diochus); Smetana, 1982: 27 (synonym of Diochus); Smetana, 2004: 624 (synonym of Diochus); Löbl & Löbl, 2015: 1007 (synonym of Diochus). Type species: Rhegmatocerus punctipennis Motschulsky, 1858 fixed by subsequent designation by Blackwelder, 1943: 455.
Diagnosis. the genus Diochus can be distinguished from all other genera within the tribe Diochini by the following characteristics: a) body slender, more or less fusiform (Fig. 3), usually small to medium in body-size (3–6 mm); b) head small, bearing two paired punctures quadrately located on disc (Fig. 1); a medial elevation between eyes only present in male (Fig. 4 A, 5A, 6A), sometimes underdeveloped or missing at all (Fig. 7 A); c) maxillary palpus markedly long, penultimate and segment II extremely long and of same length; penultimate obconical; last segment small and acicular (Fig. 5 P); d) labial palpus short, last segment slender and stalked (Fig. 6 M); e) neck nearly 1/3 width of head, with furrow or groove on both dorsal and ventral surface, also with three pairs of cervical sclerites (Fig. 4 K–L); f) pronotum oval shaped, anterior angles abruptly bended ventrally, with five paired punctures on surface (Fig. 1); g) elytra not overlapping at suture; normally with paired adsuture and admedian rows, each composed of five punctures (Fig. 1); h) protarsi somewhat dilated; i) antesternal plate transparently sclerotized, bearing numerous bubble-like protrusions (Fig. 2); j) superior line of hypomeron bending toward prosternum before anterior angle of pronotum, but not joining inferior line (Fig. 2); k) distinct intercoxal apophysis and transverse ridge on prosternum (Fig. 2); l) obvious longitudinal ridge, transverse ridge, oblique furrow on mesoventrites (Fig. 2); m) discrimen of metaventrites distinctly elevated (Fig. 2); n) aedeagus sclerotized to various extent: totally sclerotized (Fig. 4-1 E), partly membranous (Fig. 5-1 E, 6-1E), or occasionally totally membranous (Fig. 7-1 E); parameres symmetrical and extraordinarily thin (Fig. 5-1 E, 6-1E); possessing different kinds of sperm pump (Fig. 4-1 G, 5-1G, 6-1G, 7-1G); o) female spermetheca tube-like, apically dilated (Fig. 4-1 J, 5-1J, 6-1J); segment IX symmetrical and narrowing into stylus-like apical portion with sharp spine-like apex (Fig. 4-1 O, H); tergite X distinctly broad (Fig. 4- 1 I, 5- 1I, 6- 1I), sternite X atrophied (Fig. 4-1 L, 6-1L), or absent (Fig. 5-1; Fig. 7- 1).
description: Published as part of Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2016, Taxonomy of the genus Diochus Erichson, 1839 (Coleoptera: Staphylinidae, Staphylininae, Diochini) in China with descriptions of four new species, pp. 1-30 in Zootaxa 4127 (1) on pages 2-3, DOI: 10.11646/zootaxa.4127.1.1, http://zenodo.org/record/258266