Dichodontus crassus Silvestre 2001

Pathomwattananurak, W., Jeenthong, T. & Tasen, W., 2019, To the knowledge of the subfamily Dynastinae (Coleoptera: Scarabaeidae) from Thailand, Far Eastern Entomologist 393, pp. 1-10 : 4-6

Dichodontus crassus Silvestre 2001

Figs 11–15

Dichodontus crassus Silvestre 2001: 225 . Type locality: Malaisie, Cameron Highlands

( MNHN; images of holotype and paratype available on Muséum National d’Histoire Naturelle

Website (2019) were examined.).

MATERIAL EXAMINED. Thailand: Surat Thani Province, Ban Na Sarn

District, Plai Nam Subdistrict, 15-28.IX 1987, 1♂ (THNHM-I-10053, THNHM) ,

4♀ (THNHM-I-10054 to THNHM-I-10057, THNHM), J. Nabhitabhata leg. ;

Nakhon Si Thammarat Province, Khao Nan National Park, San Yen , 18.IV 2007 ,

7♀ (THNHM-I-10058 – THNHM-I-10064, THNHM), W. Jaitrong leg.

male genitalia, dorsal view; 14 – male genitalia, ventral view; 15 – male genitalia, lateral view.

DIAGNOSIS. Adult male ( Figs 11–12 ). BL 33 mm, BW 19 mm. Body entirely black. Elytra smooth and shiny. This species is closely related to Dichodontus grandis Ritsema, 1882 (Sumatran species), but can be separated from the latter by the following characteristics of the male genitalia ( Figs 13–15 ): 1) parameres sym-

metry, in dorsal view, paramere weakly concave laterally (strongly concave in D.

grandis); 2) lateral margin with a small tooth at middle length (relatively large tooth in D. grandis ); 3) in lateral view, paramere subtriangular and bluntly angulate apically. In dorsal view this species is relatively broader than in D. grandis (BL/BW

1.71–1.86 in D. crassus vs 1.84–2.00 in D. grandis ).

DISTRIBUTION. Thailand (new record) and W Malaysia (Silvestre, 2001).

REMARKS. The male specimen deposited in THNHM is relatively small com-

pared with the holotype (BL 47 mm), but the specimen agreed well with the images of a paratype (available on https://science.mnhn.fr/institution/mnhn/collection/ec

/ item/ec4451). Male genitalia of the Thai specimen also agreed well with the images and original description of this species (see Fig. 6 in Silvestre, 2001). Body index

(BL/BW) is 1.74 (BL/BW 1.71–1.86 in the type series).

Figures

Figs. 11 – 15. Dichodontus crassus: 11– male, lateral view; 12 – male, dorsal view; 13–

Figs 6–10. Clyster itys: 6 – male, lateral view; 7 – male, dorsal view; 8 – male genitalia,