Onychogomphus sp. Matsuki et al . (1990: 16 Kitagawa et al . (1994: 12 Ophiogomphus guangdongensis Chao 1994 Chao (1994: 73–75 Melligomphus sp. Wilson (1995a: 116–117 Melligomphus moluami Wilson 1995b Saito & Ogata (1995: 33–34 Wilson (1997a: 32–33 Wilson (2003: 238–239 Wilson (2004a: 240–241 Gomphidae of Guangdong & Hong Kong, China (Odonata: Anisoptera) 2177 Wilson, Keith Duncan Peter Xu, Zaifu Zootaxa 2009 2009-08-06 2177 1 62 3ZL73 (Chao 1994) Wilson & Xu 2009 Chao 1994 [151,688,527,553] Insecta Gomphidae Melligomphus Animalia Odonata 38 39 Arthropoda species guangdongensis comb. nov.   Figs. 20(a–j), 21(a–j)     Onychogomphussp.: Matsuki (1989: 30–32, figs 8, 12, 16, Hong Kong);  Matsuki et al. (1990: 16, Hong Kong);  Kitagawa et al. (1994: 12, Hong Kong).    Ophiogomphus guangdongensis Chao 1994:  Chao (1994: 73–75, figs 1–9, type-loc. male, Heishiding, Guangdong).    Melligomphussp.:  Wilson (1995a: 116–117, 123, 125, Hong Kong).    Melligomphus moluami Wilson 1995b: Wilson (1995: 325–329, figs 5–14, type-loc. Mount Butler, Hong Kong);  Saito & Ogata (1995: 33–34, fig. 52, Hong Kong);  Wilson (1997a: 32–33, Hong Kong);  Wilson (2003: 238–239, Hong Kong);  Wilson (2004a: 240–241, Hong Kong). syn. nov.   Remarks:The single male specimen described by Chao (1994)measured: abd. + app. 37 mmand hw 29 mm. These are virtually the same measurements as given for male  Melligomphus moluamiby Wilson (1995), which are abd. + app. 36 mmand hw 29.0 mm. The descriptions also closely match and the drawings of caudal and secondary genitalia are comparable. There is a slight difference in wing venation but the two taxa are clearly synonymous. Wilson (1995) was unaware of Chao (1994), which was published in December 1994whereas Wilson’s manuscript was submitted in September 1993, more than a year earlier, but published in September 1995. Chao (1994)described  guangdongensisin subgenus  Ophiogomphus( Ophionurus) Carle, but lacking a hooked posterior appendix, it does not belong in this subgenus.  Chao (1953b)published a very detailed account of the external morphology of  Onychogomphus ardensNeedham. Later, Chao (1990)selected  ardensas the genotype species for the new genus  Melligomphus, which he established to receive Chinese onychogomphines with, inter alia, superior appendages shorter than inferior appendages and without markedly hooked tips, as in  Lamelligomphus. Chao (1990)created a key to the genera of Chinese Onychogompinae but there are obvious errors in this key with respect to  Melligomphus. In couplet (8) of Chao's (1990)key  Melligomphusis required to possess: "A 2arising from the triangle". The wings of the genotype  M. ardenswere figured in Chao (1953b)and these figures are reproduced here ( Figs. 19a–b). They clearly illustrate A 2arising from the anal vein between the anal crossing (= cu-a) and the subtriangle. In fresh specimens of  M. ardensfrom GuangdongA 2also arises between the anal crossing and triangle ( Fig. 18i). This character will not separate  Melligomphusfrom  Ophiogomphus. In couplet (8) of Chao's (1990)key  Melligomphuswas also separated from  Ophiogomphusbased on two other characters, viz. (i) anal loop 1 or 2-celled compared with 3-celled anal loop in  Ophiogomphusand (ii) superior appandages slightly shorter than inferior appendages. In Chao’s drawings of  M. ardensthe hindwing anal loops clearly possess two cells but  Ophiogomphus sinicusChaoalso has 2-celled anal loops ( Fig. 24e). All the numerous  sinicusspecimens examined in this paper possess 2-celled anal loops. A superior appendage longer than inferior appendage is charcteristic of  Ophiogomphus sensu strictobut in Asian  Ophiogomphus( Ophionurus) sinicusthe superior appendages are shorter than inferior appendages. Of the three characters Chao used in his key to separate  Melligomphusfrom  Ophiogomphus, none reliably serve to split Asian  Ophiogomphus( Ophionurus)from  Melligomphus!   FIGURE 20(a–j):  Melligomphus guangdongensis comb. nov., Guangdong, ♂, from Chao (1994)— (a) abdomen, dorsal, (b) head, frontal, (c) synthorax, (d) caudal appendages, dorsal, (e) penile organ, lateral, (f) left basal hindwing, (g) right basal hindwing, (h) caudal appendages, lateral, (i) anterior hamulus, (j) posterior hamulus.   FIGURE 21(a–j):  Melligomphus guangdongensis comb. nov., Hong Kong. [a–i] from Wilson (1995)— (a) ♀, head, thorax and basal abdomen, lateral, (b) ♀, occiput, frontal, (c) ♀, caudal abdomen, postgenital plate, (d) ♂, penile organ, ventral, (e) ♂, penile organ, lateral, (f) ♂, caudal appendages, lateral, (g) ♂, caudal appendages, dorsal, (h) larvae, dorsal, (i) ♂, hamuli, (j) ♀, hindwing. In Chao’s drawings of  guangdongensis( Figs. 20a–j) the superior appendages are clearly shorter than the inferior appendages but the anal loop is 3-celled, however, in three  guangdongensis(=  moluami) specimens examined from Hong Kongthe anal loop is 2-celled ( Fig. 21j). Chao (1994)elected to place  guangdongensisin the subgenus  Ophiogomphus( Ophionurus)based on: "posterior hamulus produced into a short finger-like process and the inferior anal appendage with a well devloped dorsolateral spine." Carle (1986)divided the genus  Ophiogomphusinto three subgenera, namely:  OphionuroidesCarle,  OphionurusCarle and  OphiogomphusSelys. When Carlecreated the subgenus  Ophionurusit was characterised as follows, “Posterior hamulus elongate with a hook-like apex, male epiproct with a well developed dorsolateral spine, female postocellar ridge well developed medially”. The posterior hamulus of  guangdongensisis elongate and acuminate and not hook-like. The inferior appendage has a dorsolateral spine in the subgenus  Ophionurusbut not in  Ophiogomphus sensu stricto. Species within the genus  Melligomphus, where the males are known, do not possess inferior appendages with a sub-basal spine i.e  Melligomphus ardens(Needham),  Melligomphus cataractusChao & Liuand  Melligomphus ludens(Needham). However, the presence or absence of an inferior appendage with a sub-basal spine or tooth may not be a useful character at generic level (it is a subgeneric character in  Ophiogomphus). The general structure of the penile organ and hamuli may serve as more reliable generic characters. The penile organ of  Melligomphus ardens( Fig. 19c) strongly resembles  guangdongensis(cf Figs. 20e& 21d–e). The median segment of both species' penile organs features a prominent, somewhat flattened, posterior lobe (also known as the prepuce or preputial fold) and ventrally a pair of raised and prominent (nose–like), heavily scleritized structures to which the bilobed distal segment is attached. These scleritized structures are also prominent in  Melligomphuscongeners i.e.  Melligomphus cataractus( Fig. 19e) and  Melligomphus ludens( Fig. 19f). However the penile organ of  Ophiogomphus sinicusalso possesses these features (cf Fig. 19d& 24d), but not quite so pronounced. Perhaps the most reliable character to distinguish  Melligomphusfrom  Ophiogomphusis the structure of the posterior hamulus. In general appearance  guangdongensisstrongly resembles  Melligomphuscongeners, especially  Melligomphus ludens(see Wilson 1995b), whereas there is no general resmblance to species of  Ophiogomphus( Ophionurus)or  Ophiogomphus sensu stricto. In summary the genus  Melligomphusis reliably characterised by: (i) inferior anal appendages of male slightly longer than superior appendages, (ii) both branches of superior appendages more or less parallel, (iii) penile organ with a prominent postgenital lobe and pair of raised, prominent, nose-like scleritized structures, (iv) anal triangle of male 4-celled, (v) anal loop 2-celled or occasionally 1 or 3-celled, and (vi) posterior hamulus with an acuminate tip, not overtly hook-like. The only species known from Chinain the subgenus  Ophiogomphus( Ophionurus)is  sinicus Chao (1954), which bears very little resemblance to its North American congeners (see remarks section under  sinicusbelow).   Distribution: China( Guangdong& Hong Kong).