Systematics of the endemic New Zealand brachiopod Neothyris

Pleistocene and Recent species of the endemic New Zealand brachiopod Neothyris are redescribed on the basis of internal and external characters. A new extant species is recorded from the Chatham Rise, east of New Zealand. A new subspecies of the living Neothyris lenticularis is distinguished north of Cook Strait. Neothyris ovalis (Hutton, 1886) is relegated to subspecific rank in N. campbellica (Filhol, 1885). A new subspecies of Neothyris campbellica appears to be a Nukumaruan geographical variant, known only from the Wairarapa and Hawke's Bay districts. The use of X‐ray radiographs in the study of brachial loops is discussed.