Gnathoncus nannetensis (Marseul, 1862)

Lackner, Tomáš, 2020, A review of Gnathoncus of Southeast Asia (Coleoptera: Histeridae: Saprininae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 397-409 : 403

Gnathoncus nannetensis (Marseul, 1862)

( Figs 2 , 25–34 , 52 )

Saprinus nannetensis Marseul, 1862: 499 (original description).

Gnathoncus urganensis Reitter, 1896: 307 (original description) – synonymized by RΕιർΗΑRƉτ (1941): 162.

Gnathoncus suturalis Ganglbauer, 1899: 380 (original description) – synonymized by MΑƵUR (1984): 104.

Gnathoncus nannetensis : RΕιττΕR (1896): 308 (keyed); KRΥƵΗΑΝοඏඌΚιΙ +|RΕιർΗΑRƉτ (1976):114, 117 (keyed, redescription); MΑƵUR (1984): 105 (catalogue); ÔΗΑRΑ (1994): 215, figs 130, 131, 132, 135 (key, redescription); MΑƵUR (1997): 214 (catalogue); MΑƵUR (2004): 92 (catalogue); MΑƵUR (2011): 176 (catalogue); LΑർΚΝΕR et al. (2015): 114 (catalogue).

Note. This species was very thoroughly redescribed and figured in detail by ÔΗΑRΑ (1994: 215), and the reader is referred to the redescription and detailed figures there. For the sake of better recognition of this species among others distributed in Southeast Asia, the habitus ( Fig. 2 ) as well as pygidium ( Fig. 52 ) and male genitalia ( Figs 25–34 ) are reproduced herein.

Differential diagnosis. In the rather shiny elytral disc, this species resembles both G. rotundatus and G. brevisternus , but differs from them in round pygidial punctures ( Fig. 52 ) and dark-brown legs ( Fig. 2 ). From G. semimarginatus it differs in the complete marginal pronotal stria; from G. vietnamicus in the absence of longer apical fragment of the sutural elytral stria, and from G. sechuanus in the absence of strong alutaceous microsculpture of the elytra.

Biology. This species is predominantly found in bird nests, but has also been recorded in burrows of small mammals, on (mostly bird) carrion, decaying fish, animal droppings, etc. (KRΥƵΗΑΝοඏඌΚιΙ +| RΕιർΗΑRƉτ 1976).

Distribution. Widespread in almost the entire Palaearctic Region; from Southeast Asia recorded from China: Guangdong (LΑർΚΝΕR et al. 2015).

Figures

Figs 1–5. Dorsal (1–4) and ventral (5) habitus of SE Asian Gnathoncus species. 1 – G. brevisternus Lewis, 1907; 2 – G. nannetensis (Marseul, 1862); 3 – G. rotundatus (Kugelann, 1792); 4–5 – G. sechuanus sp. nov.

Figs 16–51. Male genitalia of SE Asian Gnathoncus species. 16–24 – G. brevisternus Lewis, 1907: 16–18 – VIII sternite and tergite (16 – ventral view; 17 – dorsal view; 18 – lateral view). 19–20 – IX and X tergites (19 – dorsal view; 20 –lateral view). 21–22 – IX sternite (spiculum gastrale) (21 – ventral view; 22 – lateral view). 23–24 – aedeagus (23 – dorsal view; 24 – lateral view). 25–34 – G. nannetensis (Marseul, 1862) (after ÔΗΑRΑ 1994). 25–27 – VIII sternite and tergite (25 – apical half in ventral view; 26 – dorsal view; 27 – lateral view).28–30 – aedeagus (28 – apex, apical view; 29 – dorsal view; 30 – lateral view). 31–32 – IX and X tergite (31 – dorsal view; 32 – lateral view). 33–34 – IX sternite (spiculum gastrale) (33 – ventral view; 34 –lateral view). 35–42 – G. rotundatus (Kugelann, 1792) (after ÔΗΑRΑ 1994). 35–37 – VIII sternite and tergite (35 – apical half in ventral view; 36 – dorsal view; 37 – lateral view). 38–39 – IX and X tergite (38 – dorsal view; 39 – lateral view). 40 – IX sternite (spiculum gastrale), ventral view. 41–42 – aedeagus (41 – dorsal view; 42 – lateral view). 43–51 – G. sechuanus sp. nov. 43–45 – VIII sternite and tergite (43 – ventral view; 44 – dorsal view; 45 – lateral view). 46–47 – IX and X tergites (46 – dorsal view; 47 –lateral view). 48–49 – IX sternite (spiculum gastrale) (48 – ventral view; 49 – lateral view). 50–51 – aedeagus (51 – dorsal view; 51 – lateral view)

Figs 52–53. Pygidial microsculptures. 52 – Gnathoncus nannetensis (Marseul, 1862); 53 – G. rotundatus (Kugelann, 1792) (from SτοർΚ- ΜΑΝΝ 1957).