Gilvossius is a genus of thalassinidean crustacean erected in 1992 from former members of the genus Callianassa. It is distinguished from Callianassa by the rounded, rather than squarish telson, and by the absence of the first two pleopods in males. The genus contains the following species:Gilvossius arguinensis Sakai, Türkay, Beuck & Freiwald, 2015 Gilvossius candidus (Olivi, 1792) Gilvossius convexus (de Saint Laurent & Le Loeuff, 1979) Gilvossius fredericqae Felder & Robles, 2020 Gilvossius howellorum Felder & Robles, 2020 Gilvossius persicus (Sakai, 2005) Gilvossius rotundicaudatus (Stebbing, 1902) Gilvossius setimanus (De Kay, 1844) Gilvossius tyrrhenus (Petagna, 1792) Gilvossius whitei (Sakai, 1999)SynonymsGilvossius bouvieri (Nobili, 1904) accepted as Paratrypaea bouvieri (Nobili, 1904) Gilvossius brachytelson (Sakai, 2002) accepted as Cheramoides brachytelson (Sakai, 2002) Gilvossius chichijimaensis Sakai, 2015 accepted as Paratrypaea chichijimaensis (Sakai, 2015) Gilvossius diaphorus (Le Loeuff & Intes, 1975) accepted as Callianassa diaphora Le Loeuff & Intes, 1974 Gilvossius gravieri (Nobili, 1906) accepted as Paratrypaea bouvieri (Nobili, 1904) Gilvossius marchali (Le Loeuff & Intes, 1974) accepted as Callianassa marchali Le Loeuff & Intes, 1974 Gilvossius pacificus (Guzmán & Thatje, 2003) accepted as Neotrypaea pacifica (Guzmán & Thatje, 2003) Gilvossius tyrrhena (Petagna, 1792) accepted as Gilvossius tyrrhenus (Petagna, 1792) Gilvossius uncinatus (H. Milne Edwards, 1837) accepted as Neotrypaea uncinata (H. Milne Edwards, 1837)