Gnathoncus rotundatus (Kugelann, 1792)

Lackner, Tomáš, 2020, A review of Gnathoncus of Southeast Asia (Coleoptera: Histeridae: Saprininae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 397-409 : 403-404

Gnathoncus rotundatus (Kugelann, 1792)

( Figs 3 , 35–42 , 53 )

Gnathoncus rotundatus : MΑƵUR (2011): 176 (catalogue); LΑർΚΝΕR et al. (2015): 114 (catalogue); LΑർΚΝΕR +| LΕඌർΗΕΝ (2017): 33, figs 90–110, 754 (mentioned).

Notes. Complete synonymy and references of this species are given by LΑർΚΝΕR (2010: 118) and the reader is referred to them there. For the sake of completeness we list the references of all works containing G. rotundatus since 2010 above.

This species has been very thoroughly redescribed and figured in detail by ÔΗΑRΑ (1994: 220) and the reader is referred to the redescription there. For the sake of better recognition of this species among others spread in Southeast Asia, the habitus ( Fig. 3 ) as well as pygidium ( Fig. 53 ) and male genitalia ( Figs 35–42 ) are reproduced herein. The differential diagnosis of this species is also provided.

Differential diagnosis. Gnathoncus rotundatus differs from G. semimarginatus 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. From the most similar G. brevisternus it differs in much smaller, inconspicuous prosternal fovea and narrower prosternum, as well as in different structure of the aedeagus (compare Figs 41 and 23 ). From G. nannetensis it differs in oval-shaped pygidial punctures, differently-shaped male VIII sternite and tergite (compare Figs 25–27 and 35–37 ) and in reddish-brown legs.

Biology. A typical synanthrope found mostly in anthropogenic settings, but collected also on carrion, bird nests, excrements, decaying vegetable matter, birch sap, occasionally even in anthills (KRΥƵΗΑΝοඏඌΚιΙ +| RΕιർΗΑRƉτ 1976).

Distribution. Holarctic Region, Republic of South Africa, Chile, Saint Paul Island (MΑƵUR 2011). From SEAsia reported from Taiwan and China: Gansu (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).