Bahrain
A fish, the Convict Zebra Sole Zebrias captivus (GBIF) (Google Books) (IUCN), is known only from two specimens collected off Bahrain.
Sea squirts known only from Bahrain include Aplidium rubripunctum (ResearchGate WM pdf).
Arthropods known only from Bahrain include an ant Lepisiota bahrainensis (PLAZI), a tortricid moth Bactra atopa (BHL), and a xanthid crab Palapedia apeli (GBIF).
Marine molluscs described from Bahrain and apparently not collected since include Paradrillia lithoria (fig. 20 at BHL) (BHL) and Actaeon pulchrior (fig 26 at BHL) (BHL).