Abstract
The genus Fectola Iredale, 1915 (Mollusca: Pulmonata: Sigmurethra: Punctoidea) is analysed using the panbiogeography research program. This paper is written for comparison with an earlier communication of mine, published in 1978, which treated the same group of nine species from the more limited Darwinian perspective. A subsumation of vicariance cladistic methodology by panbiogeographic methodology is demonstrated thus helping to resolve a major inhibiting opposition in science. The morphology and biogeography of species of Alsolemia Climo, 1981, Loisthodon n.gen., Mitodon n.gen., Ptychodon Ancey, 1888, and Zelandiscus n.gen. are discussed in relation to those of Rotadiscus Pilsbry, 1926, the latter newly recorded from New Zealand. Zelandiscus is introduced for Ptychodon (Solemia) elevata Climo, 1978 and Z. worthyi n.sp.; Rotadiscus protoinsularis n.sp. is described; and Ptychodon (Solemia) delicatula Climo, 1978, P. monoplax hiarara Dell, 1954, and P. m. takahea Dell, 1955 are synonymised with Endodonta (Thaumatodon) monoplax Suter, 1913. Endodonta (Charopa) benhami Suter, 1909 is placed here in the monotypic genus Loisthodon. Horizontal and vertical vicariance in rotadiscine taxa is analysed and integrated in a relative way with the results of the same matrix-analysis technique for Fectola-form. The resulting synthesis (“high systematics”) clearly shows that the biogeographic symmetries of Fiordland and Nelson are relative and that neither region owes its faunal diversity either to Alpine Fault slippage or to extinctions during glacial maxima. The way form comes together in space/ time (morphogeny) along the New Zealand geosyncline is expressed not only in the relative structure of the “Auckland”, “Wellington”, and“Dunedin” nodes but also in the way snail morphologies of the eastern and western oceanic mobilisms (the “beams” of “dispersal”) recombine in geologically-integrated form-makings and mobilisms (epigenesis) in and between the nodes in question. Using the same imagery, the “Auckland”, “Wellington”, and “Dunedin” nodes are, themselves, one node (a triune) by virtue of mutual illumination.