Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 41e): GS2620, S27/f8459, "Barytellina mudstone" downstream from Hautotara Bridge, Makara River, southern Wairarapa, Nukumaruan (GNS)
(Pl. 41f): GS2620, S27/f8459, "Barytellina mudstone" downstream from Hautotara Bridge, Makara River, southern Wairarapa, Nukumaruan (GNS)
Beu & Maxwell (1990): Chapter 15; p. 313; pl. 41 e,f.
Synonymy: Barytellina crassidens Marwick 1924a, p. 26; Barytellina anomalodonta Finlay 1924b, p. 473; Barytellina tertia Fleming 1943, p. 194.
Type species of Barytellina Marwick, 1924
Classification: Tellinidae: Tellininae
Description: Moderate-sized for family (28-35 mm long), with very thick shell for family, variable in shape from almost equidimensional to relatively long and narrow; exterior almost smooth, lightly polished, with weak growth ridges, weakly flexed to right at posterior end, and with prominent rounded ridge down the dorsal posterior angle of right valve. Hinge unusually large and thick for family, with very large, thick, triangular, posterior cardinal tooth in right valve and 2 narrower ones in left valve, no anterior lateral teeth but large, prominent posterior lateral teeth in both valves. Adductor scars small, deeply impressed; pallial sinus extremely deep, extending to anterior adductor scar, lower margin confluent with pallial line.
Comparison: Barytellina crassidens is easily recognised by its thick shell, its smooth, often polished exterior, and its unusually massive hinge for a tellinid; the very large, triangular cardinal tooth of the right valve and the large posterior tooth are particularly distinctive. It is uncertain whether an earlier (Waipipian-Nukumaruan) more elongate species (B. tertia) can be distinguished from a later, shorter one (Nukumaruan-Haweran); Marwick (1948, p. 20) referred to the variability and consequent taxonomic difficulty of the genus, and subsequent collections have only made the situation more clouded. We follow Beu & Maxwell (1990, p. 313) and Beu (2006, p. 266) and recognise only one species. Beu (2006) pointed out earlier records of the genus in Longford beds (Tongaporutuan) in the Murchison district, so its rarity before Waipipian results from the usual problem of the poor fossil record of near-shore environments.
Distribution: Waipipian-Haweran; Nukumaru Beach, west of Wanganui, Nukumaruan (type of B. crassidens), presumably from either Tewkesbury Formation or, more probably, an estuarine horizon in Maxwell Group (uppermost Nukumaruan, and estuarine to non-marine); Rissington, Hawke's Bay, Nukumaruan (type of B. anomalodonta). Common in the Otahuhu well shellbed, Auckland (Waipipian); in a few estuarine beds high in the type Nukumaruan section at Nukumaru, Wanganui; in estuarine gravelly mudstone (with common Pseudocardium and Zeacumantus) on Kaiwaka South Road, near Devil's Elbow, Hawke's Bay; and in estuarine mudstone at the top of the marine sequence in Makara River, downstream from Hautotara Bridge, east of Martinborough, Wairarapa (Nukumaruan); also scattered at many Nukumaruan localities in Hawke's Bay and Wairarapa. Abundant at one Castlecliffian locality in the Rangitikei Valley, and a single fresh, large valve is known from Haweran (oxygen isotope stage 9) marine terrace cover beds on Brunswick Terrace, west of Wanganui. Possibly coeval or younger specimens are known also from upper Manukau Harbour at the mouth of Papakura Stream, Manurewa, Auckland.
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)