Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 42k): GS10849, V20/f8572, Devil's Elbow mudstone, top of north face of Devil's Elbow hill, Napier-Wairoa Highway, Nukumaruan (GNS)
Beu & Maxwell (1990): Chapter 15; p. 324; pl. 42 k.
Synonymy: Siphonalia nodosa var. conoidea Hutton 1893, p. 41 (not Purpura conoidea Zittel 1864, p. 37, secondary homonym); Aethocola taitae Marwick 1924c, p. 197; Austrofusus (Austrofusus) taitae, Beu & Maxwell 1990, p. 324, pl. 42k.
Description: Rather small for genus (30-50 mm high, but rarely over 40 mm high), moderately tall, with stepped spire and moderately long, strongly twisted canal with prominent, long, scaly fasciole bordered by narrow ridge. Whorls with weakly concave sutural ramp, sharp shoulder angle at 0.7 height of spire whorls, lightly contracted below shoulder to moderately prominent peribasal angulation. Sculpture of prominent, narrow, widely spaced spiral cords, 1 below suture and about 10 on shoulder angle, sides, and base of last whorl more prominent than others, with narrow secondary thread in centre of each interspace; all thickened into moderately high to very prominent, narrowly rounded, spine-like nodules where they cross the prominent, widely spaced axial costae. Nodule size highly varied (figured specimen is more weakly sculptured than most others, as most strongly sculptured shells have broken apertures and canals). Outer lip weakly thickened, lirate within. Protoconch small, narrowly conical, of 3.5 smooth whorls.
Comparison: Nukumaruan species of Aethocola (A. taitae, Hawke's Bay; A. cottoni, southern Wairarapa) are considerably smaller than and have more prominent fascioles than the Castlecliffian-Recent species A. glans (Pl. 49c); A. cottoni has low, rounded nodules, whereas most specimens of A. taitae have large, sharply pointed, "prickly" nodules. Adoption of Aethocola is discussed under A. acuticostata, Pl. 6m.
Hutton (1893, p. 41) seems to have been using Zittel's species name rather than proposing a new taxon when he stated that his variety conoidea was "perhaps the same as" Purpura conoidea Zittel, but the two taxa have different type localities of different ages ("Petane, Matapiro", Nukumaruan, for Siphonalia nodosa var. conoidea; Awatere Valley, Opoitian or Kapitean, for Purpura conoidea) and as both have been referred in modern times to Austrofusus (i.e., Aethocola), they are at least secondary homonyms, and Marwick's name A. taitae must be used for the species that is so widespread and abundant in mudstone facies in Hawke's Bay.
Distribution: Nukumaruan. "Petane, Matapiro" (types of Siphonalia nodosa var. conoidea); "blue clays below limestone, Kikowhero Creek, Ngaruroro River", Matapiro Station, central Hawke's Bay (type of Aethocola taitae). Abundant in mudstone facies throughout central Hawke's Bay.
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)