Diochus Erichson, 1839

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, Zootaxa 4127 (1), pp. 1-30 : 2-3

publication ID	https://doi.org/ 10.11646/zootaxa.4127.1.1
publication LSID	lsid:zoobank.org:pub:9E858916-3F3A-4D87-B987-B62CE241CED0
DOI	https://doi.org/10.5281/zenodo.6063241
persistent identifier	https://treatment.plazi.org/id/7C5887A3-FFE1-B25F-FF6A-F82C32D0FB25
treatment provided by	Plazi
scientific name	Diochus Erichson, 1839
status

Treatment

Genus Diochus Erichson, 1839 View in CoL

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 View FIGURE 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 View FIGURE 4 A, 5A, 6A), sometimes underdeveloped or missing at all ( Fig. 7 View FIGURE 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 View FIGURE 5 P); d) labial palpus short, last segment slender and stalked ( Fig. 6 View FIGURE 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 View FIGURE 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 View FIGURE 4 E), partly membranous ( Fig. 5-1 View FIGURE 5 E, 6-1E), or occasionally totally membranous ( Fig. 7-1 View FIGURE 7 E); parameres symmetrical and extraordinarily thin ( Fig. 5-1 View FIGURE 5 E, 6-1E); possessing different kinds of sperm pump ( Fig. 4-1 View FIGURE 4 G, 5-1G, 6-1G, 7-1G); o) female spermetheca tube-like, apically dilated ( Fig. 4-1 View FIGURE 4 J, 5-1J, 6-1J); segment IX symmetrical and narrowing into stylus-like apical portion with sharp spine-like apex ( Fig. 4-1 View FIGURE 4 O, H); tergite X distinctly broad ( Fig. 4- 1 View FIGURE 4 I, 5- 1I, 6- 1I), sternite X atrophied ( Fig. 4-1 View FIGURE 4 L, 6-1L), or absent ( Fig. 5-1 View FIGURE 5 ; Fig. 7- 1 View FIGURE 7 ).