Neptunea decemcostata

{{Short description|Species of mollusc}}

{{Speciesbox

|image = Neptunea decemcostata (YPM IZ 034030).jpeg

|genus = Neptunea

|species = decemcostata

|authority = (Say, 1826)

}}

Neptunea decemcostata, the New England neptune, is a species of Neptunea and the state shell of Massachusetts.{{Cite web |title=Massachusetts Facts: State Symbols |url=https://www.sec.state.ma.us/divisions/cis/historical/concise-facts.htm |website=Secretary of the Commonwealth of Massachusetts}} It is sometimes considered a subspecies of Neptunea lyrata, which it shares its common name with.