Introducing Phallostethus cuulongCredit: L.X. Tran, ZootaxaThe male of this new species of fish sports its sex organ on its chin, though it looks nothing like the members on humans and other mammals.
Male and female, side by sideCredit: L.X. Tran and K. Shibukawa, ZootaxaThese freshly collected male (A) and female (B) specimens of Phallostethus cuulong were found in Vietnam's Mekong Delta.
Penis-head breakdownCredit: L.X. Tran, ZootaxaCalled the priapium, the sex organ includes two bony attachments, a rod-like structure (toxactinium) and a serrated hook (ctenactinium), used to clasp the female while mating.