Dodatak:Popis mekušaca, U
Ub
uredi- Uberella
Ul
uredi- Ultraphysella
Um
uredi- Umbilia
- Umbilibalcis
- Umbonium
- Umbraculida
- Umbraculidae
- Umbraculoidea
- Umbraculum
Un
uredi- Uncancylus
- Unciherpia
- Uncimenia
- Undulostrea
- Unedogemmula
- Ungulina
- Ungulinidae
- Ungulinoidea
- Uniandra
- Unidentia
- Unidentiidae
- Unio
- Uniomerus
- Unionetta
- Unionidae
- Unionoida
- Unionoidea
Up
uredi- Uperotus clava J. F. Gmelin, 1791
- Uperotus panamensis P. Bartsch, 1922
Mollusca → Bivalvia → Myoida → Pholadoidea → Teredinidae → Teredininae
Ur
uredi- Urgorria
- Urosalpinx
- Uroteuthis
- Urumella
Ut
uredi- Utahphysa
- Utralvoherpia
†Utschamiellidae Kolesnikov 1977
urediMollusca → Bivalvia → Uniomorphi → Trigoniida → Pseudocardinioidea
Utterbackia Baker, 1927
uredi- Utterbackia imbecillis (Say 1829)
- Utterbackia peggyae (Johnson 1965)
- Utterbackia peninsularis Bogan & Hoeh 1995
Mollusca → Bivalvia → Unionoida → Unionoidea → Unionidae
- Uttleya ahiparana (Powell, 1927)
- Uttleya arcana Marwick, 1934 †
- Uttleya marwicki Powell, 1952
- Uttleya williamsi Powell, 1952
Mollusca → Gastropoda → Neogastropoda → Muricoidea → Muricidae → Ergalataxinae
Uv
uredi- Uvanilla
Uz
uredi- Uzumakiella