GNS Science

Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)

New Zealand Cenozoic Mollusca

Pelicaria vermis (Martyn, 1784) form acuminata (Marwick, 1924)


(Pl. 42e): GS6677, T27/f6762, Maurioho Stream, east of Martinborough, southern Wairarapa, early Nukumaruan (GNS)

Beu & Maxwell (1990): Chapter 15; p. 320; pl. 42 e.

Synonymy: Struthiolaria sulcata Hector 1886, p. 50 (in part; not of Jonas, 1829); Struthiolaria acuminata Marwick 1924b, p. 185; Struthiolaria media Marwick 1924b, p. 187; Pelicaria mangaoparia Vella 1953, p. 40; Pelicaria rotunda Vella 1953, p. 41; Struthiolaria (Pelicaria) wellmani Neef 1970, p. 472; Pelicaria acuminata, Beu & Maxwell 1990, p. 320, pl. 42e; Pelicaria vermis, Beu 2009

Classification: Struthiolariidae

Description: Large for genus (25-60 mm high), highly variable in spire height, from markedly shorter than to markedly taller than aperture; with narrow to moderately wide, flat to weakly concave sutural ramp, evenly convex to weakly quadrate whorls, and normal, wide Pelicaria aperture with weakly sinuous, varicate outer lip meeting thickened, smooth, narrow inner lip at shallow anterior notch. Spiral sculpture highly variable, but all forms with 3 prominent, wide, widely spaced spiral cords on spire whorls and 4 cords plus a few fine intermediate threads and about 4-6 basal cords on last whorl; most specimens have very low, rounded nodules on major spiral cords of last 2-3 whorls. Protoconch typical of genus (see P. vermis form convexa).

Comparison: Beu (2009) interpreted the huge range of variation of Pelicaria forms in Nukumaruan-Recent faunas as comprising a single direct-developing species, P. vermis (Martyn, 1784) (other than the Mangapanian-early Nukumaruan species P. granttaylori Beu, 2009, which seems to have evolved from P. zelandiae). However, as some of the more extreme forms were separated and described by Beu & Maxwell (1990), their separation as "forms" is maintained here; they retain some utility in biostratigraphy, provided their variation and intergradation is kept in mind. Pelicaria vermis form acuminata is exceedingly variable in size, spire height, shell width, prominence of the spiral cords, width and depth of the sutural ramp or shallow sutural channel, and prominence of nodules on the spiral cords. Wide shells with relatively low spires from the early Nukumaruan of southern Wairarapa were named P. rotunda by Vella (1953), small specimens with a relatively quadrate whorl-section from deep-water facies of early Nukumaruan age in southern Wairarapa were named P. mangaoparia by Vella (1953), and a rather small specimen from the early Nukumaruan of Castlepoint, Wairarapa, was named Struthiolaria media by Marwick (1924), but large samples from these areas show that all these forms intergrade, and there is no doubt that they are all part of the variation of a single biospecies.

Neef (1970) described an evolutionary sequence in the Mangahao district, northwestern Wairarapa, from the Waipipian P. canaliculata (Pl. 36q), with a deeply channelled suture and extremely high spiral cords with undercut edges, through the early Mangapanian P. clarki, similar to P. canaliculata but with a shallower sutural channel and square-sided cords, and the mid-late Mangapanian P. marima, with a shallow sutural channel and spiral cords only slightly more prominent than in P. acuminata, to an early Nukumaruan form of P. acuminata (named P. wellmani by Neef). This apparently records the gradual, anagenetic evolution of P. vermis from P. canaliculata, but this evolution has not been seen outside the Mangahao district. In Petane siltstone at Watchman Hill, Ahuriri Lagoon, Napier, central Hawke's Bay, P. vermis form acuminata intergrades with P. vermis form convexa in early Nukumaruan rocks.

Distribution: Early Nukumaruan. Te Awaite Cutting, White Rock Road, east of Martinborough, southern Wairarapa (type of S. acuminata); Castlepoint, east Wairarapa coast, early Nukumaruan (type of S. media); high outcrop of Mangaopari Mudstone with three prominent concretionary horizons, south bank of Mangaopari Stream c. 500 m upstream from junction with Makara River, southern Wairarapa (type of P. mangaoparia); junction of Whakarua Stream and first southern tributary, Whakarua Road, one km east of Martinborough-Gladstone road, Whangaehu Valley, southern Wairarapa (type of P. rotunda); upper Marima Sandstone, north side of large, narrow bend of Mangahao River c. one km northeast of Marima, Mangahao district, west of Pahiatua, northern Wairarapa (loc. 1022, Neef 1970, p. 443, fig. 5; type of P. wellmani).

See also P. vermis form convexa (Pl. 42b), P. vermis form fossa (Pl. 42a) and P. vermis (pl. 47u), all now considered to be part of the variation of one species (early Nukumaruan-Recent), occurring in most shallow-water environments of Nukumuruan and younger age throughout New Zealand.

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
ISBN 978-0-478-19705-1
ISSN 1177-2441
(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)


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