GNS Science

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

New Zealand Cenozoic Mollusca

Mioawateria personata (Powell, 1942)


(Pl. 27g): GS3341, J32/f7585, abandoned brickworks quarry, Karoro, near Greymouth, Westland, Waiauan (GNS)

Beu & Maxwell (1990): Chapter 12; p. 250; pl. 27 q.

Synonymy: Awateria personata Powell 1942, p. 130; A. (Mioawateria) personata

Type species of Mioawateria Vella, 1954

Classification: Conidae: Raphitominae

Description: Small for family (height 5-7 mm), biconic, spire strongly gradate, about half total height. Protoconch conical, probably about 4 whorls when complete, decussately sculptured (i.e., by diagonally reticulate threads). Teleoconch of up to 4 whorls, which are strongly shouldered at or near middle on spire, sutural ramp with prominent subsutural fold; last whorl broadly excavated, with short neck. Axial sculpture of narrow, opisthocline costae extending from shoulder angle to lower suture on spire whorls, and across base (but not onto neck) on last whorl. Costae of rounded-triangular cross-section, with interspaces considerably wider than one costa; 15-22 costae on penultimate whorl. Sutural ramp with narrow, prosocline costellae reaching from upper suture to shoulder angle on early whorls but largely confined to subsutural fold on later whorls, costellae more numerous than axial costae. Spiral sculpture commencing as narrow cord on shoulder, joined during growth by low, flat-topped cords on sides, penultimate whorl with 3-4 cords, last whorl with additional 15- 17 cords. Some specimens have 1-3 weak cords on sutural ramp between subsutural cord and shoulder. Aperture pyriform, columella almost straight above, curved to left below, forming short siphonal canal. Inner lip thinly callused; outer lip with very shallow, arcuate anal sinus, its apex below middle of ramp.

Comparison: Mioawateria personata is distinguished by its small size, its biconic shell with strongly angled teleoconch whorls, its very shallow anal sinus, and its decussate daphnelline protoconch. Several New Zealand turrids have previously been assigned to Mioawateria, but the only ones currently accepted here are M. personata, M. expalliata (Otaian, Hokianga district) and M. aitanga (Haweran, Te Piki, Cape Runaway) (Maxwell 1988a, p. 66-68). An unnamed species is present in Otaian rocks at Parengarenga Harbour.

Mioawateria is similar to Gymnobela Verrill, 1884, which is widely recorded from bathyal and abyssal depths in the Atlantic Ocean (Bouchet and Warén 1980, pp. 48-59). Further study may show that Mioawateria is not separable from Gymnobela, although the type species of Gymnobela (G. engonia Verrill, 1884; Recent, Western Atlantic) is much larger than M. personata and differs in sculptural style. Mioawateria is also exceedingly similar in all characters to some of the larger species assigned to Taranis Jeffreys, 1870 and, again, it is possible that Mioawateria is a synonym of Taranis. Most Taranis species have a low, paucipiral protoconch, but a few New Zealand early Cenozoic species have a typical raphitomine tall, decussate protoconch, and there is no doubt that Taranis is a raphitomine, closely related to Mioawateria.

Mioawateria is not recorded from the modern New Zealand fauna, although it seems to be represented in Indonesia and Japan by Pleurotomella extensaeformis Schepman, 1913, which occurs at depths of 460 to 730-760 m (Maxwell 1988a, p. 68). Most New Zealand records of the genus are from upper bathyal assemblages, but M. aitanga occurs in the Te Piki bed, with a shallow-water faunule of apparently mixed mid-shelf to shallow bay assemblages.

Distribution: Waiauan-Opoitian; Mangawhero Stream, Wairoa district, Opoitian (type); Karoro quarry, Greymouth (Waiauan); Kapitea Creek, Westland (Waiauan); Bell's Creek, Mangaopari Stream, southern Wairarapa (Tongaporutuan). Moderately common in Stillwater Mudstone at Karoro quarry, rare elsewhere.

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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