TL;DR: The New Zealand Recent species of Cantharidus Montfort, 1810 (3 species) and Micrelenchus Finlay, 1926 (10 species) are revised, illustrated and keyed.
Abstract: The New Zealand Recent species of Cantharidus Montfort, 1810 (3 species) and Micrelenchus Finlay, 1926 (10 species) are revised, illustrated and keyed. A new species of Cantharidus and a new Micrelenchus species are described from north of Cape Reinga. Micrelenchus huttonii (Smith, 1876) is resurrected from synonymy under M. tenebrosus (A. Adams, 1853). The following seven taxa are newly synonymised: Cantharidus opalus cannoni Powell, 1933 with C. opalus (Martyn, 1784); Cantharidus coruscans Hedley, 1916 with M. capillaceus (Philippi, 1848); Cantharidus sanguineus elongatus Suter, 1897, Gibbula micans Suter, 1897 and M. sanguineus bakeri Fleming, 1948 with Canthiridus artizona A. Adams, 1853; M. oliveri cryptus Powell, 1946 with M. sanguineus (Gray, 1843); M. parcipictus Powell, 1946 with M. tenebrosus (A. Adams, 1853); M. caelatus morioria Powell, 1933 and M. caelatus archibenthicola Dell, 1956 with M. mortenseni (Odhner, 1924). A new subgenus of Cantharidus is introduced for C. purpureus (Gmeli...
TL;DR: It is revealed that Australian and New Zealand species fall into endemic clades that have been separated for, at most, 35million years and this divergence date postdates a vicariant split by around 50million years, suggesting that, once again, long-distance trans-Tasman dispersal has played a pivotal role in molluscan evolution in this part of the world.