Comparison between Ptilohyale littoralis and Parhyale plumicornis diagnostic characters and distributions. Ptilohyale littoralis: A illustration of male (Bousfield and Hendrycks 2002) B antenna II male with brush-setae starting at the 5th peduncular segment C right uropod I with peduncular distomedial robust seta D species distribution along the Atlantic coast. Parhyale plumicornis: E illustration of male (Iaciofano and Lo Brutto 2017) F antenna II male with brush setae starting at the 4th peduncular segment G right uropod I with peduncular distolateral robust seta H species distribution along the Mediterranean and Red Sea coasts.