Variation in Fukienogomphus Prometheus (Lieftinck, 1939) Reveals Stylurus Takashii (Asahina, 1966) As a Junior Synonym, with Discussion on the Status of F. Choifongae Wilson Amp; Tam, 2006 (Odonata: Gomphidae)

We investigate variation of body pattern in Fukienogomphus prometheus (Lieftinck, 1939) and notice the similarity of its female to Stylurus takashii (Asahina, 1966), an enigmatic species whose male is still unknown. We then review the taxonomic history of S. takashii and compare its holotype female with the female F. prometheus. Our results show S. takashii is a junior synonym to F. prometheus. We elucidate the intraspecific variation of F. prometheus and provide information for its ecology and distribution in Taiwan. We also discuss the similarities between the adults of Fukienogomphus choifongae Wilson Tam, 2006 and F. prometheus which in future studies may prove to be conspecific and will require to synonymise the two names. Finally, we confirm the genus Stylurus Needham, 1897 is not distributed in Taiwan.