Notes on the Subgenus Pelicaria

Abstract

The marine, medium-sized gastropod Pelicaria, a subgenus of Struthiolaria, is endemic to New Zealand. Extinct species of the subgenus evolved rapidly in separate parts of New Zealand during the early Pliocene; they are common fossils in shallow-water sediments and are useful for local correlation. Sixteen species and subspecies of Pelicaria are illustrated and the following new species and subspecies are described: clarki, marima, wellmani, vermis flemingi, vermis powelli, vermis bradleyi, vermis grahami and canaliculata becki. This paper has three main parts, and sections on phylogeny and systematics. The first part describes the distribution of races of Recent Pelicaria. Fossils identical to the recent races are present in Pleistocene marine sediments at Te Piki and Wanganui. Four cool periods and four warmer periods are recognised in the sediments at Wanganui by their contained Pelicaria fauna. The second part is largely an account of an extinct lineage of Waipipian, Waitotaran and Hautawan (Plio-Pleistocene) chronospecies of Pelicaria, which were used by the writer to zone the Marima Sandstone at Marima, near Pahiatua, in the northern Wairarapa district (North Island of New Zealand). The main feature of the lineage is that the younger shells are progressively more streamlined than the older. Three zones are recognised: S.(P.) wellmani (upper), S.(P.) “acuminata” * The middle zone is referred to as the S.(P.) “acuminata” zone, because S.(P.) acuminata, the zonal fossil in the southern Wairarapa is not itself present at Eketahuna, but is represented by the related form S.(P.) marima. View all notes (middle) and S. (P.) canaliculata ( lower ). The third part is a summary of the extinct Pliocene — lower Pleistocene species and races of Pelicaria which evolved separately in the Wanganui, Hawera, Awatere, and southern Wairarapa districts. The chief feature of the evolving lineages is the streamlining of the shell. Probable migrations of Pelicaria from basin to basin and the phylogeny of the subgenus are discussed.