An unusual Nystia species (Gastropoda, Truncatelloidea) from the early Rupelian of the Isle of Wight (Hampshire Basin, England)

In the lower part of the Hamstead Member of the Bouldnor Formation (lower Rupelian, Oligocene) in the Isle of Wight (Hampshire Basin, England) a common gastropod has hitherto been incorrectly identified as Lutetiella conica (Prévost, 1821), a hydrobioid species from Lutetian (middle Eocene) strata of the Paris Basin. We have re-assessed its relationship and describe it as Nystia conoidalis n. sp. in the family Emmericiidae. Recognition of its relationships had been obscured by the vestigial development of the terminal varix and the less frequent and less severe occurrence of shell decollation.