Polynoncus gibberosus Scholtz, 1990, 1428

Costa-Silva, Vinícius, Strümpher, Werner P., Thyssen, Patricia J. & Vaz-de-Mello, Fernando Z., 2024, Taxonomic revision of the South American genus Polynoncus Burmeister, 1876 (Coleoptera: Scarabaeoidea: Trogidae), Journal of Natural History 58 (1 - 4), pp. 14-166 : 95-96

Polynoncus gibberosus Scholtz, 1990

( Figures 35 , 38 )

Polynoncus gibberosus Scholtz, 1990: 1428 (original description); Diéguez 2008: 18 (redescription); Gómez 2008: 516 (key to Argentinean species); Zidek 2013: 10 (checklist); Zidek 2017: 101 (checklist); Smith 2017: 95 (distribution and comments); Mondaca 2023: 209 (checklist from Chile)

Type specimen examined (through detailed photographs). HOLOTYPE. (♂ USNM – Figure 38 ) First label [white, aged, handwritten]: ‘Concepcion / Des 1986 / L. Peña’. Second label [white with red border, Clarke Scholtz’s handwriting]: ‘ Polynoncus / gibberosus / C.H. Scholtz 1988 / HOLOTYPE’.Third label [red]: ‘Type Number / 104758 / U. S. N. M’. Fourth label [white, printed]: ‘USNMENT / [QR Code] / 01476215’ ( Figure 38d ). Type locality: ‘ Concepción’ , Chile .

Differential diagnosis. Polynoncus gibberosus is similar to P. brevicollis and P. aeger , differing from the latter by lacking the subhumeral ridge (which is present in P. aeger ). Also, P. gibberosus is distinguished from P. brevicollis by having anterior half of lateral margin of elytra slightly crenulated and basal and latero-basal pronotal tubercles distinctly raised. In P. brevicollis , the anterior half of lateral margin of elytra is entirely smooth, and the basal and latero-basal tubercles of the pronotum are poorly raised.

Polynoncus gibberosus and P. brevicollis both have the median lobe of male aedeagus in rhomboid shape apically, with a distinct longitudinal keel dorsally. In Polynoncus gibberosus this keel extends to the apex of the median lobe,while ending in the apical third in P.brevicollis , never reaching the apex. For details of description, see Scholtz (1990, p. 1428).

Geographic distribution. Polynoncus gibberosus is endemic to southern Chile ( Figure 35 ). Scholtz (1990) cited this species from two localities (records of type series). Later, Diéguez (2008) cited additional localities/records, expanding the known geographical range of Polynoncus gibberosus . Our findings corroborate Diéguez’s (2008) conclusions.

Examined non-type material (24 specimens). CHILE: Araucanía (IX Region), Lonquimay , February 1994, S . Castro leg . (1♀ CEMT); Lonquimay , February 1994, S . Castro leg . (4 CVMD); Nahuelbuta National Park , 1200 m, 37.783°S, 73.000°W, 22 November 2004, J .E . Barriga and T . Iogging leg . (1♀ CJEB) . Bío-Bío (VIII Region), Alto Cayucupil, Cordillera de Nahuelbuta , 25–31 January 1997,V .M . Diéguez leg . (1♂ and 6 unsexed CVMD); Alto Cayucupil, Cordillera de Nahuelbuta , 25–31 January 1997, V .M . Diéguez leg . (1♂ CEMT); Alto Cayucupil, Cordillera de Nahuelbuta , 8–13 March 1998, Danilo Escobar leg . (1 CVMD); Alto Cayucupil, Cordillera de Nahuelbuta , 3–9 March 1997, Danilo Escobar leg . (2 CVMD). Los Lagos (X Region), Osorno, Fundo Porvenir , 13 March 1982, D . Jackson leg . (1♂ CVMD) . Los Ríos (XIV Region), Valdivia , 10–12 January 1980, E . Krahmer leg . (1 MNNC); Valdivia , 12 January 1991, E . Arias leg . (1 MNNC); Valdivia, Llancahue Park , 11 December 2001, M . Galvéz leg . (1 CVMD); Valdivia, Llancahue Park , 15 February 2002, M . Galvéz leg . (2♂ CVMD); Valdivia , December 1994, S . Castro leg . (1 CVMD).

Figures

Figure 35. Distribution map of Polynoncus gemmiferus (red circles), P. gibberosus (green triangles), and P. juglans (blue squares) in South America. The records with a black dot in the centre indicate the type locality of the respective species.

Figure 38. Holotype of Polynoncus gibberosus Scholtz, 1990: habitus in a, dorsal and b, lateral view; c, dorsal view of male genitalia; d, labels. Photos by Karolyn Darrow (USNM).