Granimedon, Assing, 2015

Assing, Volker, 2015, Two new genera of Medonina from China and Japan (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 47 (1), pp. 191-206 : 193-194

Granimedon nov.gen.

Type species: Granimedon anguliceps nov.sp.

E t y m o l o g y: The name is composed of the Latin noun granum (alluding to the granulose pronotum) and the generic name Medon. The gender is masculine.

D e s c r i p t i o n: Species of relatively small size, 3.3-5.5 mm; habitus (e.g., Figs 1 , 13 ) similar to that of Orsunius ASSING, 2011 .

Head (e.g., Figs 2 , 14 ) transverse, with more or less distinctly marked posterior angles, and with dense to very dense umbilicate punctation. Ventral aspect ( Fig. 3 ) with narrow impunctate band in the middle, without distinct gular sutures. Labrum ( Fig. 3 ) transverse, anterior margin broadly and shallowly emarginate, without teeth and without deep and narrow median incision. Left mandible with three, right mandible with four distinct molar teeth; basal tooth on both mandibles enlarged ( Figs 2-3 ). Maxillary palpus ( Fig. 5 ) four-jointed, palpomeres II and III slender; apical palpomere minute and of conical shape. Labial palpus three-jointed, shaped as in Fig. 6 . Ligula ( Fig. 7 ) deeply bifid, furnished with numerous stout sensillae.

Pronotum (e.g., Figs 2 , 14 ) transverse, widest anteriorly, and with weakly marked to obsolete posterior angles; punctation dense, distinctly and rather coarsely granulose (e.g., Fig. 8 ). Prosternum sharply keeled in the middle ( Fig. 3 ).

Elytra with dense punctation. Process of mesoventrite without median keel, apically acute, and reaching nearly half-way between mesocoxae. Protarsomeres I-IV unmodified. Metatarsomere I approximately as long as combined length of II and III.

Abdomen with fine and dense punctation, and with distinct microsculpture.

3: sternite VII without pronounced modifications; sternite VIII oblong and unmodified (e.g., Figs 10 , 18 ); aedeagus (e.g., Figs 11-12 , 19-20 ) weakly sclerotized, small in relation to body size, and dorso-ventrally more or less distinctly compressed.

C o m p a r a t i v e n o t e s: In general appearance (size, habitus), Granimedon resembles Orsunius , but is distinguished by the shape of the labrum ( Orsunius : anterior margin with distinct median incision, except for the species of the O. granulosus group), the absence of distinct gular sutures ( Orsunius : present and not contiguous; absent only in the O. granulosissimus group), the presence of four distinct molar teeth on the right mandible ( Orsunius : three teeth, occasionally with an additional minute fourth tooth; exception: O. granulosus group), the enlarged basal tooth on both mandibles, the slender maxillary and labial palpi, the unmodified protarsomeres I-IV ( Orsunius : in most species dilated), the posteriorly strongly convex male sternite VIII (without posterior excision), and the weakly sclerotized aedeagus with a relatively short and apically very acute ventral process ( Orsunius : aedeagus usually laterally compressed, with longer and more strongly sclerotized ventral process (exception: O. granulosus group). For illustrations of Orsunius see ASSING (2011, 2014).

Granimedon shares several character conditions (granulose punctation of the pronotum, shape of labrum, right mandible with four distinct teeth) with the species of the Orsunius granulosus group, but differs by the absence of gular sutures, the much coarser punctation of the head and pronotum, the longer palpi, the enlarged basal tooth on both mandibles, the absence of a posterior excision of the male sternite VIII, and the aedeagal morphology. As emphasized earlier ( ASSING 2014), the O. granulosus group forms a distinct lineage within Orsunius , was attributed to this genus only with hesitation, and may in fact represent a distinct genus.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Thethreespeciesincludedin Granimedon were discovered in the region of Gejiu, southeastern Yunnan, China. Since all them have fully developed hind wings, it seems likely that the genus is widespread in the Oriental and southern East Palaearctic regions. The species were collected by sifting leaf litter and debris in forests, beneath shrubs, and in arable land at altitudes between 1010 and 1890 m.

Figures

Figs 1-8: Granimedon anguliceps nov.sp.: (1) habitus; (2) head and pronotum in dorsal view; (3) head and prothorax in ventral view; (4) median portion of head; (5) maxilla; (6) labium; (7) ligula; (8) median portion of pronotum. Scale bars: 1-3: 1.0 mm; 4-8: 0.1 mm.

Figs 13-20: Granimedon effeminatus nov.sp.: (13) habitus; (14) head and pronotum in dorsal view; (15) median portion of head; (16) antenna; (17) median portion of pronotum; (18) male sternite VIII; (19-20) aedeagus in lateral and in ventral view. Scale bars: 13: 1.0 mm; 14, 16: 0.5 mm; 18- 20: 0.2 mm; 15, 17: 0.1 mm.

Figs 9-12: Granimedon anguliceps nov.sp.: (9) male sternite VII; (10) male sternite VIII; (11) aedeagus in lateral view; (12) apical portion of aedeagus in ventral view. Scale bars: 9-10: 0.5 mm; 11-12; 0.2 mm.