Polynoncus tenebrosus ( Harold, 1872 )

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 : 153-154

Polynoncus tenebrosus ( Harold, 1872)

( Figures 58 , 65 )

Trox tenebrosus Harold, 1872: 130 , 191 (original description); Preudhomme de Borre 1886: 77 (checklist); Arrow 1912: 62 (catalogue); Blackwelder 1944: 219 (checklist – as ‘ tenebrosa ’); Vaurie 1962: 132 (redescription)

Trox (Polynoncus) tenebrosus : Scholtz 1982: 17 (catalogue)

Polynoncus tenebrosus : Scholtz 1986a: 362 (systematics); Scholtz 1990: 1448 (redescription); Zidek 2013: 17 (checklist); Zidek 2017: 109 (checklist)

Type specimen examined. HOLOTYPE. ( MNHN – Figure 65 ) First label [light brown with orange border, Edgar von Harold’s handwriting]: ‘Amer. mér / T. / tenebrosus / typ. Harold’. Second label [white, aged, with black border, typeset]: ‘Ex-Musaeo / E. Harold’. Third label [red, typeset]: ‘Type’. Fourth label [light green]: ‘Muséum Paris / ex Coll. / R. Oberthür / 1952’. Fifth label [white,aged, Edgar von Harold’s handwriting]: ‘tenebrosus / mihi’. Sixth label [red, typeset]: ‘HOLOTYPE’. Seventh label [white with black border, typeset]: “ HOLOTYPE / Polynoncus / tenebrosus ( Harold, 1872) . Eighth label [white, typeset]: ‘MNHN / EC10492’ ( Figure 65c ). Type locality: Cited by Harold (1872) as ‘ höchst wahrscheinlich Südamerika ’ (South America). Considering the geographical distribution known for this species, the type specimen was likely collected in the Andean regions of Ecuador.

Differential diagnosis. This rare species is most similar to P. sallei , but differs from it by having erect black setae on the surface of elytral tubercles, which are absent in the latter species.

Polynoncus tenebrosus also bears some resemblance to P. ecuadorensis , but can be distinguished from it by the colour of the setae on the antennae. The setae are very dark in P. tenebrosus , while in P. ecuadorensis the setae are distinctly yellow. Furthermore, the humeral calli are obsolete in P. tenebrosus and well defined in P. ecuadorensis . For details of description, see Vaurie (1962) and Scholtz (1990).

Geographic distribution. Polynoncus tenebrosus is endemic to Ecuador ( Figure 58 ).

Examined non-type material (1 specimen). ECUADOR: Chimborazo, Guano , 2683 m, 10 July 2007, manual collection, no collector (1♂ CEMT) .

Figures

Figure 58. Distribution map of Polynoncus pilularius (red circles), P. sallei (green triangles), and P. tenebrosus (blue squares) in South America. The records with a black dot in the centre indicate the type locality of the respective species.

Figure 65. Holotype of Trox tenebrosus Harold, 1872 (now Polynoncus tenebrosus): habitus in a, dorsal and b, lateral view; c, labels. Photos by Christophe Rivier (MNHN).