Sya
- Syamus
Syl
- Sylon
- Sylviocarcinus
Sym
- Symethis
- Symmius
- Sympagurus
- Sympleustes
- Sympodomma
- Sympronoe
Syn
- Synagogidae
- Synagogidae
- Synalpheion
Synalpheus
- Synamphisopus
- Synanarthrura
- Synapseudes
- Synapseudoides
- Synaptotanais
- Synarmadillo
- Synarmadilloides
- Synasellus
- Synasterope
- Synaxidae
- Syncaris
Syncassidina Baker, 1928
- Syncassidina aestuaria Baker, 1928
Crustacea → Malacostraca → Isopoda → Sphaeromatoidea → Sphaeromatidae
- Synchelidium
- Syncyamus
- Syndexamine
- Synerythrops
- Syneurycope
- Syngastes
- Synidotea
- Synischia
- Synopia
- Synopiidae
- Synphoxus
- Synsynella
- Syntripsa
- Synurella
Syr
- Syrrhoe
- Syrrhoites
Sys
- Syscenus
- Systellaspis
- Systroplax