Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 49o): Castlecliff, Wanganui, Castlecliffian (TM5764, GNS, from an early collection)
Beu & Maxwell (1990): Chapter 16; p. 369; pl. 49 o.
Synonymy: Monoptygma casta A. Adams 1853b, p. 223; Monoptygma pura A. Adams 1854b, p. 820; Actaeon dianae A. Adams 1855c, p. 59; Admete(?) ambigua Hutton 1885b, p. 320; Leucotina ambigua; Odostomia sulcata Hutton 1885b, p. 319 (not of Edwards, 1878); Actaeon huttoni Cossmann 1895, p. 173 (new name for Odostomia sulcata Hutton, preoccupied); Acteon praestitus Finlay 1924a, p. 105 (new name for Odostomia sulcata Hutton, preoccupied); Tenuiactaeon ambiguus, Beu & Maxwell 1990, p. 369. pl. 49o. Beu (2004, pp. 225-226) provided a long synonymy, most not repeated here.
Type species (as the synonym Leucotina niphonensis A. Adams, 1860) of Leucotina A. Adams, 1860
Description: Large for family (15-32 mm high), inflated, with tall, weakly stepped spire (equal to aperture in height), large, long last whorl with evenly rounded anterior, lachrymiform aperture, no anterior canal or notch, and straight, thin outer lip. Inner lip weakly thickened, narrowly reflected over narrow umbilical slit, raised into a single low, rounded plait at top of columella; parietal area without callus. Sculpture of wide, shallow, widely spaced, punctate spiral grooves only, apart from weak growth lines. Protoconch inverted, of about 1-1.5 smooth, inflated whorls, with bulbous initiation, which is partly immersed.
Comparison: Beu (2004) reassesed the species of the Leucotina casta - L. pura complex, and considered them all to be conspecific. This is another of the widely distributed, tropical western Pacific species, provided with many synonyms in Japan and eastern Australia, that extended its range as planktotrophic larvae to New Zealand during warm Pleistocene interglacial periods. It is easily recognised by its large, anteriorly rounded, "tear-drop-shaped" aperture, fine, punctate spiral grooves like those of Acteon, very low ridge on the columlla, immersed tip of the protoconch, but its much taller spire than any acteonid.
Distribution: Late Nukumaruan-Recent; "Wanganui", i.e., Castlecliff section, Wanganui, Castlecliffian (types of both Odostomia sulcata and Admete(?) ambigua). The earliest record in New Zealand is in Pukekiwi Shell Sand (high in Maxwell Group, latest Nukumaruan) at Ototoka Beach, west of Wanganui, where it is quite common. A late Nukumaruan specimen is also known from the Ruamahanga River cliffs at Gladstone, Wairarapa. Thereafter L. casta was common in almost all formations of Castlecliffian and Haweran age throughout Wanganui basin, in the Parnasus area in North Canturbury, at Cape Kidnappers, Hawke's Bay, at Ohope Beach and Te Piki in the Bay of Plenty, and in a wide range of scattered Haweran and Holocene localities throughout New Zealand, as far south as Teer Formation, Cascade Point, South Westland. Three apparently authentic Recent specimens are also known from Northland. It is particularly common in the "Austrovenus beds" of the upper Kidnappers Group at Cape Kidnappers, and apparently parasitised A. stutchburyi (among other bivalves) in New Zealand. After Castlecliffian time, the species seems to have been much more common in estuarine environments rather than in the near-shore shelf siltstone facies it inhabited during Castlecliffian time.
Cite this publication as: "A.G. Beu and J.I. Raine (2009). Revised
descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990). GNS
Science miscellaneous series no. 27."
© GNS Science, 2009
(Included with a PDF facsimile file copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version from: Publications Officer, GNS Science, P.O. Box 30368 Lower Hutt, New Zealand)