Diochus Erichson

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 : 3

Key to species of the genus Diochus Erichson recorded from China

1 Left mandible with blunt teeth ( Fig. 10 H); body small, not longer than 3 mm; protarsi not dilated ( Fig. 10 L); distribution in China not confirmed................................................................. D. pulchellus Cameron

- Left mandible with sharp teeth; body usually longer than 3 mm; protarsi dilated ( Fig. 4 M)............................ 2

2 Antennomere II obviously shorter than III ( Fig. 4 G).......................................................... 3

- Antennomere II slightly shorter than (or subequal in length to) III ( Fig. 5 G)....................................... 5

3 Body large, ca. 6.0 mm; head length 1.2 times longer than width; distribution in China not confirmed.. D. japonicus Cameron

- Body medium sized, ca. 5.1 mm; head length 1.3-1.4 times longer than width...................................... 4

4 Right mandible with a long and sharp tooth ( Fig. 9 J); aedeagus not well-sclerotized, with paired stick-like apical sclerites ( Fig. 9 E-G); distribution in China not confirmed........................................... D. conicollis (Motschulsky)

- Right mandible with a smaller and not very sharp tooth ( Fig. 4 J); aedeagus well-sclerotized, with paired horn-like apical scler- ites ( Fig. 4-1 E, F).................................................................... D. bicornutus sp. nov.

5 Body small sized, 3.3 mm; aedeagus with T-shaped internal sclerite ( Fig. 8 ); distribution in China not confirmed........................................................................................ D. antennatus (Motschulsky)

- Body slightly longer than 3.4, or distinctly longer (ca. 4 mm); aedeagus without distinct sclerite....................... 6

6 Head not possessing a median elevation between eyes.................................... D. membranaceus sp. nov.

- Head possessing a median elevation between eyes ( Fig. 1, medial elevation)....................................... 7

7 Gular sutures deep and confluent before base ( Fig. 6 D).................................... D. bisegmentatus sp. nov.

- Gular sutures normally deep and not confluent before base ( Fig. 5 D).......................... D. ampullaceus sp. nov.

Figures

FIGURE 4. Diochus bicornutus sp. nov.: A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. elytra, ventral view; G. antennae; H. labrum; I. left mandible; J. right mandible; K. neck, dorsal view; L. neck & cervical sclerites, ventral view; M. proleg; N. mesoscutellum; O. basal visiable four segments of abdomen, dorsal view; P. labial & maxillary palpi, ventral view. Scale bars 0.30 mm.

FIGURE 5. Diochus ampullaceus sp. nov.: A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. elytra, ventral view; G. antennae; H. labrum; I. left mandible; J. right mandible; K. neck, dorsal view; L. neck & cervical sclerites 1, ventral view; M. proleg; N. mesoscutellum; O. basal visiable three segments of abdomen, dorsal view; P. maxillary palpi, ventral view; Q. antesternal plate. Scale bars 0.10 mm.

FIGURE 6. Diochus bisegmentatus sp. nov.: A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. elytra, ventral view; G. antennae; H. labrum; I. left mandible; J. right mandible; K. neck, dorsal view; L. neck & cervical sclerites, ventral view; M. labial palpi; N. mesoscutellum; O. basal visiable four segments of abdomen, dorsal view. Scale bars 0.10 mm.

FIGURE 8. Diochus antennatus (Motschulsky, 1858): posterior margin of sternite VIII, sternite X, aedeagus of the male syntype.

FIGURE 9. Diochus conicollis (Motschulsky, 1858): A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. elytra, ventral view; G. antennae; H. labrum; I. left mandible; J. right mandible; K. neck, dorsal view; L. neck, ventral view; M. proleg; N. mesoscutellum; O. basal visiable four segments of abdomen, dorsal view. Scale bars 0.30 mm.

FIGURE 10. Diochus pulchellus Cameron, 1918: A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. antennae; G. labrum; H. left mandible; I. right mandible; J. neck, dorsal view; K. neck; L. proleg; M. mesoscutellum; N. basal visiable four segments of abdomen, dorsal view. Scale bars 0.30 mm.