A new fossil provannid gastropod from Miocene hydrocarbon seep deposits, East Coast Basin, North Island, New Zealand

Provanna marshalli sp. nov. is described from Early to Middle Miocene-age fossil hydrocarbon seep localities in the East Coast Basin, North Island, New Zealand, adding to 18 modern and three fossil species of the genus described. Modern species are well represented at hydrothermal vent sites as well as at hydrocarbon seeps and on other organic substrates in the deep-sea, including sunken wood and whale falls. All described fossil Provanna species are restricted to hydrocarbon seep deposits, with a few reports of suspected fossil specimens of the genus from other chemosynthetic environments such as plesiosaurid carcasses, and the oldest occurrences are dated to the Middle Cenomanian (early Late Cretaceous). The New Zealand fossil species is the most variable species of the genus described to date, and may be conspecific with, or antecedent to, a poorly sampled, undescribed modern species found at seep sites off the East Coast of North Island. The microstructure of a fossil Provanna species is reported here for the first time, and found to be comparable to some modern specimens of the genus.