Stylurus amicus ( Needham 1930 )

Wilson, Keith Duncan Peter & Xu, Zaifu, 2009, Gomphidae of Guangdong & Hong Kong, China (Odonata: Anisoptera) 2177, Zootaxa 2177, pp. 1-62 : 23

Stylurus amicus ( Needham 1930)

Figs. 10 (a–h)

Gomphus amicus Needham 1930 : Needham (1930: 63–64, pl. 6, fig. 5, ♂, type-loc.: "Foochow or Amoy", Fujian; note 1 ♀ from Jiangsu reidentified by Chao, 1953 as Stylurus clathratus Needham ); Needham (1941: 150, 152, Fujian & Jiangsu); Needham (1944: 155, 157, Fujian & Jiangsu; virtually the same paper as preceeding paper i.e. Needham 1941); Chao (1954: 420–432, figs 65–69, Fujian & Sichuan).

Gomphus szechuanicus Chao (1953: 418–420, figs 61–64, ♀, type-loc Sichuan); Asahina (1978b: 235, ♀, Sichuan).

Stylurus amicus Needham 1930 : Asahina (1978a: 6, ♀, Fujian); Sun & Sui (1984: 47–48, figs 35a–d, Fujian); Chao & Xu (1986: 35–37, figs 1–15, larvae & synonymy with S. szechuanicus ; Fujian & Sichuan); Chao (1990: 111–116, figs 1–29, Fujian & Sichuan); Zhang (1999: 260–261, figs 24.92a–h, Fujian & Sichuan); Hua (2000: 12, Fujian, Jiangsu, Sichuan); Wilson & Reels (2001: 182, Hainan); Wilson (2005: 144, Guangxi).

Specimens: 1 ♂ (No. 24416), Linjiang, 1 viii 2003, coll. ZX.

Remarks: Carle (1986) raised the subgenus Stylurus Needham 1897 of Gomphus Leach 1815 to genus, based primarily on the rod-like form of the anterior hamulus, the structure of the male cerci, the short form of the subgenital plate, short and wide frons (dorsum of frons length 4 x width) and absence of burrowing hooks on the larval tibia ( Needham et al. 2000). The subgenital plate is longer than other species of Stylurus but S9, which is 1.5 times length of S8, is also much longer in S. amicus than other members of the genus ( Figs. 10d & 10h).

The yellow lateral synthoracic stripes along the mespimeron and metepisternum are conjoined in Fujian and Sichuan specimens but these stripes are clearly separated in the male specimen collected from Linjiang ( Fig. 10b). Otherwise the yellow pattern is similar and there are no discernable structural differences. There are two distinct bulges in the anterior margin of the transverse sclerite (spiracular dorsum) anterior to the synthoracic collar ( Fig. 10c). This species is newly recorded from Guangdong . There is a photo of female Stylurus amicus taken 11 vii 2005 by Vincent Kalkman at Longsheng , Guangxi , which has been posted on the Asiadragonfly website ( Kalkman 2008). The lateral synthoracic pattern is similar to the Guangdong specimen with a narrow but distinct black stripe along the interpleural suture between mespeimeron and metepisternum ( Fig. 10h). This photo represents the first record of this species from Guangxi .

Distribution: China (Fujian, Guangdong, Guangxi, Hainan & Sichuan).