Thermosipho Kantor et al., 2013: 2188.
Type species: Eosipho auzendei Warén & Bouchet, 2001, by original designation.
Diagnosis (emended from Fraussen & Stahlschmidt, 2016): Shell medium to large, up to 70 mm in length, thin, dark brownish in coloration. Shell form broadly oviform with moderately wide, short spire that is usually corroded. Siphonal canal short and not well defined, open. Subsutural ramp lacking. Whorls inflated, completely smooth and lacking in significant sculpture except fine lines. Protoconch unknown. Periostracum thick, dark brown, adherent, with dense axial lamellae that are most evident on the subsutural zone. Operculum thick, corneous, brown, with terminal nucleus, semi-oval in shape and smaller than the aperture.
Distribution: Hydrothermal vents in the East Pacific. Known from the East Pacific Rise between 17 and 23° N and the Pacific–Antarctic Ridge between 31 and 38°S (Warén et al., 2006).
Remarks: See under Enigmaticolus.
Included species: Thermosipho auzendei (Warén & Bouchet, 2001) (original combination: Eosipho auzendei).