Hybovalgus sexdentatus Arrow, 1944

Ricchiardi, Enrico, 2017, Revision of Chinese mainland Hybovalgus Kolbe, 1904, with description of a new species, and Excisivalgus Endrödi, 1952 reduced to synonymy with Hybovalgus (Coleoptera: Scarabaeidae), European Journal of Taxonomy 340 (340), pp. 1-32 : 20-22

Hybovalgus sexdentatus Arrow, 1944

Fig. 8 A–F

Hybovalgus sexdentatus Arrow, 1944: 238 .

Hybovalgus sexdentatus – Ma 1995: 197, fig. 169.

Type material

Lectotype

LAOS: ♂, Ban Naban, 15 Mar. 1915, R. Vitalis de Salvaza leg. ( NHM).

Paralectotypes

LAOS: 1 ♂, Ban Naban, 18°54′23″ N, 102°54′12″ E, 15 Mar. 1915, R. Vitalis de Salvaza leg. ( NHM); 1 ♀, Xieng Khouang ( Khoueng Xieng Khouang ), 19°30′00″ N, 103°30′00″ E, 20 May 1915, R. Vitalis de Salvaza leg. ( NHM).

Other material examined

LAOS: 41 ♂♂ ( ZFMK), 2 ♂♂ ( ERC), Ban Saleui, Phou Pan Mts , 20°12′ N, 104°01′ E, 1300–1900 m, 11 Apr.–15 May 2012, C. Holzschuh leg.; 45 ♂♂ ( ZFMK), 10 ♂♂, 1 ♀ ( ERC), same data but 1–31 May 2001; 1 ♂, Ban Saleui, Phu Pan Mts , Apr.–May 2012, local collectors ( ERC).

VIETNAM: 1 ♂ ( NMER), 1 ♂ ( ERC), Cao Bang Prov., vic. Vin Den, Nui Piac Oac Nt. Res. 22°33′53″ N, 105°52′53″ E, 900–1300 m, 6–10 May 2012, A. Weigel leg.

CHINA: 1 ♂, Shandong, Kiautschau ( Jaozhou Bay ) ( ERC); 29 ♂♂, Guangxi, Mt. Dayaoshan, Linxiang , Jinxiu , 700 m, 25 Apr.–5 May 2014, HuangYuanyong & Lidong leg. ( ERC); 1 ♂, Guangxi, same data but May 2015, 1200 m, local collectors ( ERC); 1 ♂, Guangxi, Jinxiu, Huawang Shanzhuang , 24°9′28″ N, 110°7′12″ E, 600 m, 20 May 1999, Yang Xingke leg., IOZ(E) 902246 ( IZAS); 1 ♂, Guangxi, Daxin Xialei Town, 22°54′49″ N, 106°45′50″ E, 680 m, 31 Mar. 1998, Li Wenzhu leg., IOZ(E) 902246 ( IZAS); 1 ♂, Hainan, Bawangling, 19°7′43″ N, 109°6′14″ E, 8 Apr. 1984, Gu Maobing leg., IOZ(E) 902438 ( IZAS); 1 ♂, Sichuan, Dukou, Pingdi , 7 Jun. 1981, Zhang Baolin leg., IOZ(E) 902243 ( IZAS); 3 ♂♂, Yunnan, Menglong, Banna , Mengsong , 22°3′32″ N, 100°34′12″ E, 160 m, 24–25 May 1958, Wang Shuyong, Zheng Leyi and Pu Fuj leg., IOZ(E) 902255-57 ( IZAS).

Remarks

According to Arrow (1944), the type series comprised three specimens, all from Laos. In his work Arrow seemed not to realize that one of the types was a female, as he described only the male. Paulian (1961), applying the International Code of Zoological Nomenclature, amended the name of this species from H sex-dentatus ( Arrow, 1944) to H. sexdentatus , but Bacchus (1974) erroneously misspelled the name of the species again and designated the type series of three specimens, LT, one PLT male and one PLT female, but did not describe the latter, which remained undescribed until now. In this work we restate that the hyphen must be eliminated as the correct name is H. sexdentatus , and give the differences between sexes.

Identification of female (from the ♀ at ERC)

The size of females is more or less the same as that of the biggest males and the shape of the posterior margin of the pronotum is simply rounded, without protrusions or excavations. The protibia external margin has six teeth, as in the male.

At first glance the female can be distinguished by the pygidium shape: its apex is protruding and pointed ( Fig. 8D ).

Species variability

The length of males varies from 4.7 to 7.5 mm; the width from 3.0 to 4.1 mm. The only female known so far is 7.4 mm long and 3.5 mm wide.

The study of 148 specimens leads to the conclusion that the species is morphologically slightly variable. In males the only variations observed are:

- Propygidial scales and scale tufts testaceous or whitish.

- The scales on the elytron are sometimes black and testaceous, sometimes black and whitish.

- The legs are black or castaneous.

- On occasion, protibia teeth 3–4 and 5–6 are closer to one another than to 1–3.

Flight period

Specimens were collected between mid-March and the first week of June at an elevation comprised between 160 and 1900 m.

Distribution

Hybovalgus sexdentatus was described from Laos and recorded by Ma (1995) from Yunnan. New records reported here are from northern Vietnam and China (Guangxi, Hainan, Sichuan). One specimen is labelled as from Shandong (Jaozhou Bay), but this record is doutbful without further finds.

Figures

Fig. 8. A–F. Hybovalgus sexdentatus Arrow, 1944. A–B. ♂ (ERC). A. Habitus, dorsal view. B. Propygidium and pygidium. C–D. ♀ (ERC). C. Habitus, dorsal view. D. Propygidium and pygidium. E–F. PLT, ♂ (NHM). E. Aedeagus, dorsal view. F. Aedeagus, lateral view. G–J. Hybovalgus jordansi (Endrödi, 1952). G–H. ♂ (ERC). G. Habitus, dorsal view. H. Propygidiun and pygidium. I–J. PT, ♂ (HNHM). I. Aedeagus, dorsal view. J. Aedeagus, lateral view. K–N. Hybovalgus fulvosquamosus Moser, 1904. K–L. ♂ (ERC). K. Habitus, dorsal view. L. Propygidiun and pygidium. M–N. LT, ♂ (MNHUB). M. Aedeagus, dorsal view. N. Aedeagus, lateral view. Drawings: grey parts: parameres; white parts: phallobase.