Sympatric diversification in the Upper Amazon : a revision of the Eumaeine Genus Paraspiculatus (Lepidoptera: Lycaenidae) The Neotropical lycaenid hairstreak genus Paraspiculatus is unusual because of a high frequency of sympatry in the Upper Amazon Basin coupled with negligible interspecific variation of male genitalic structures and absence of male secondary sexual traits. Male sexual structures are postulated to promote species recognition by females and to contribute to reproductive isolation for which reason a high incidence of sympatry in Paraspiculatus would not be expected. A revision of Paraspiculatus was feasible because we increased the number of study specimens more than five fold (by the extensive use of rotting fish as a bait for males) and sequenced the barcode part of the mitochondrial gene CO1 for almost all species. We recognize 19 Paraspiculatus species based on male wing patterns of which ten are newly described and registered with ZooBank. We partition the 19 species into ten species complexes which are monophyletic in all analyses of morphological characters CO1 sequences and a combined dataset. Male Paraspiculatus are attracted to traps baited with rotting fish in eastern Ecuador but elsewhere this attraction is less frequent or absent. Using the behavior of other eumaeines as context we briefly discuss these observations with respect to Paraspiculatus biology. Ten of 19 Paraspiculatus species are sympatric in the Upper Amazon Basin below 1 250 m. Five of these sympatric species are from a single species complex. This instance of apparent in situ diversification is responsible for much of the sympatric diversity in Paraspiculatus in the Upper Amazon Basin. Provided by publisher