Polynoncus crypticus Diéguez, 2019

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 : 65-66

Polynoncus crypticus Diéguez, 2019

( Figures 4d , 15 , 22 )

Polynoncus crypticus Diéguez, 2019: 88 (original description); Mondaca 2023: 209 (checklist from Chile)

Type specimens examined. HOLOTYPE. (♂ MNNC – Figure 22 ) First label [yellow, typeset]: ‘ HOLOTIPO / Polynoncus / crypticus nov. sp. / V. M. Diéguez 2019 ’. Second label [white, typeset]: ‘ CHILE X REGIÓN / 7 km. W. Pargua, Ainco / 25 Diciembre 2010 / Leg. Gerardo Arriagada / Colectados a la luz’ ( Figure 22d ). Type locality: ‘ 7 km West of Pargua, Ainco’ (or Ahinco), Los Lagos (X Region), Chile.

PARATYPES (1 ♂ CEMT; 2 ♂ and 1 ♀ CVMD). First label [white with black border, typeset]: ‘Pte. Aserradero / Las Trancas – Chillán / S36°54.95 – W71°27.49 / 1295 msnm 29/XII/2016 / Col. Thomas Fichet’. Second label [yellow, typeset]: ‘ PARATIPO / Polynoncus / crypticus nov. sp. / V.M. Diéguez 2019 ’ (1 ♂ CEMT). First label [white with black border, typeset]: ‘ Chile, Llanquihue / Puerto Montt, 7 km. W de Pargua / Ainco, 25. Diciembre.2010 / leg. Gerardo Arriagada’. Second label [yellow, typeset]: ‘ PARATIPO / Polynoncus / crypticus nov. sp. / V. M. Diéguez 2019 ’ (1 ♀ CVMD). First label [white with black border, typeset]: ‘ Chile, Malleco / Cuesta Las Raíces / Febrero 2001 / leg. Alfredo Ugarte’. Second label [yellow, typeset]: ‘ PARATIPO / Polynoncus / crypticus nov. sp. / V.M. Diéguez 2019 ’ (1 ♂ CVMD). First label [white with black border]: ‘ Chile, Capitán Prat / Cochrane, 3.Febrero.1990 / leg. Luis Peña G’. Second label [yellow, typeset]: ‘ PARATIPO / Polynoncus / crypticus nov. sp. / V.M. Diéguez 2019 ’ (1 ♂ CVMD).

Differential diagnosis. Polynoncus crypticus is very similar to and often confused with P. diffluens . However, the lateral margins of the pronotum in P. crypticus are slightly crenulate with an emargination in front of the acute posterior angles. Polynoncus diffluens not have any emargination and has a round posterior angle of pronotum. For details of description and additional differential diagnosis, see Diéguez (2019, p. 88).

Geographic distribution. Polynoncus crypticus is known from a few localities in Chile, where it appears to be associated with Nothopagus ( Nothofagaceae ) forests found in central-southern Chile ( Figure 15 ). This species also occurs sympatrically with Polynoncus diffluens .

Remarks. After re-examination of the type series of Polynoncus crypticus , we observed an acute tooth on the apex of the inner margin of mesotibia present in all the males (in ventral view; Figure 22b ). The latter is clearly absent in females. This character, which was overlooked by Diéguez (2019), is externally visible and sexually dimorphic. No other material was examined beyond the type series.

Figures

Figure 4. Differential morphology in Polynoncus spp.: a, without humeral callus [P. hemisphaericus]; b, with humeral callus [P. longitarsis]. Apex of mesotibia c, with tooth [P. peruanus] and d, without tooth (white arrow) [P. crypticus]. Posterior margin of clypeus e, emarginate [P. bullatus] and f, truncate (white arrow) [P. hemisphaericus]; pronotal ridges of pronotum in g, Polynoncus argentinus and h, Polynoncus pseudogemmifer sp. n. (paratype). Scale bar: 1 mm.

Figure 15. Distribution map of Polynoncus brasiliensis (red circles), P. brevicollis (green triangles), and P. crypticus (blue squares) in South America. The records with a black dot in the centre indicate the type locality of the respective species.

Figure 22. Holotype of Polynoncus crypticus Diéguez, 2019: a, habitus in dorsal view; b, apex of mesotibia of males in ventral view (in a non-type specimen): white arrow showing the tooth in the inner margin; c, male genitalia in dorsal view; d, labels. Photos a, c–d by Marcelo Guerrero. Scale bar: 1 mm.