A new taxon of all-dark and small-sized Collared Petrel Pterodroma brevipes is described from northern Vanuatu. The description is based on six specimens held at the American Museum of Natural History collected in 1927 east of Mera Lava, in the Banks Islands. We recently discovered the new taxon to be rather abundant around the Banks Islands, apparently located its breeding grounds, and described its unique feeding behaviour. The new taxon differs from other populations of P. brevipes, which mostly breed elsewhere in Vanuatu and in Fiji, in its combination of smaller size, with shorter wings but relatively longer tail, and shorter bill and tarsus. More importantly, unlike any other populations of P. brevipes which all are polymorphic, present evidence suggests that the new taxon occurs solely in a monomorphic dark form. The new taxon is at least as distinctive as many other recognised races and even species of petrels. Subspecies rank is allocated tentatively; with future study, the new taxon might merit species status.