Melligomphus guangdongensis ( Chao 1994 ) Wilson & Xu, 2009

Wilson, Keith Duncan Peter & Xu, Zaifu, 2009, Gomphidae of Guangdong & Hong Kong, China (Odonata: Anisoptera) 2177, Zootaxa 2177, pp. 1-62 : 39-42

Melligomphus guangdongensis ( Chao 1994) comb. nov.

Figs. 20 (a–j), 21(a–j)

Onychogomphus sp. : 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).

Melligomphus sp. : 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 mm and hw 29 mm. These are virtually the same measurements as given for male Melligomphus moluami by Wilson (1995), which are abd. + app. 36 mm and 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 1994 whereas Wilson’s manuscript was submitted in September 1993, more than a year earlier, but published in September 1995. Chao (1994) described guangdongensis in 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 ardens Needham. Later, Chao (1990) selected ardens as 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 Melligomphus is required to possess: "A 2 arising from the triangle". The wings of the genotype M. ardens were figured in Chao (1953b) and these figures are reproduced here ( Figs. 19a–b). They clearly illustrate A 2 arising from the anal vein between the anal crossing (= cu-a) and the subtriangle. In fresh specimens of M. ardens from Guangdong A 2 also arises between the anal crossing and triangle ( Fig. 18i). This character will not separate Melligomphus from Ophiogomphus . In couplet (8) of Chao's (1990) key Melligomphus was also separated from Ophiogomphus based on two other characters, viz. (i) anal loop 1 or 2-celled compared with 3-celled anal loop in Ophiogomphus and (ii) superior appandages slightly shorter than inferior appendages. In Chao’s drawings of M. ardens the hindwing anal loops clearly possess two cells but Ophiogomphus sinicus Chao also has 2-celled anal loops ( Fig. 24e). All the numerous sinicus specimens examined in this paper possess 2-celled anal loops. A superior appendage longer than inferior appendage is charcteristic of Ophiogomphus sensu stricto but in Asian Ophiogomphus (Ophionurus) sinicus the superior appendages are shorter than inferior appendages. Of the three characters Chao used in his key to separate Melligomphus from Ophiogomphus , none reliably serve to split Asian Ophiogomphus (Ophionurus) from Melligomphus !

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 Kong the anal loop is 2-celled ( Fig. 21j). Chao (1994) elected to place guangdongensis in 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 Ophiogomphus into three subgenera, namely: Ophionuroides Carle , Ophionurus Carle and Ophiogomphus Selys. When Carle created the subgenus Ophionurus it 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 guangdongensis is elongate and acuminate and not hook-like. The inferior appendage has a dorsolateral spine in the subgenus Ophionurus but 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 cataractus Chao & Liu and 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 Melligomphus congeners i.e. Melligomphus cataractus ( Fig. 19e) and Melligomphus ludens ( Fig. 19f). However the penile organ of Ophiogomphus sinicus also possesses these features (cf Fig. 19d & 24d), but not quite so pronounced. Perhaps the most reliable character to distinguish Melligomphus from Ophiogomphus is the structure of the posterior hamulus. In general appearance guangdongensis strongly resembles Melligomphus congeners, 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 Melligomphus is 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 China in the subgenus Ophiogomphus (Ophionurus) is sinicus Chao (1954) , which bears very little resemblance to its North American congeners (see remarks section under sinicus below).

Distribution: China (Guangdong & Hong Kong).