Tawera

Shells of Tawera lagopus, from here.


Belongs within: Veneridae.

Tawera is a genus of venerid bivalves found from the Eocene to the present of Australia and New Zealand. It is distinguished from related genera by the absence of an anterior lateral tooth in the left valve, and the sculpture of fine, rounded concentric ridges.

Characters (from Marwick 1927): Shell oval. Lunule not impressed, bounded by incised line; escutcheon insignificant in type but stronger in basal forms; ligament exposed. Sculpture of bevelled, smooth, concentric ridges. Hinge teeth widely divergent; left valve with long, high posterior cardinal joined to nymph; moderate, bevelled, fairly deeply but unequally divided median; and long, entire, triangular, widely diverging anterior tooth, outer side of which tends to run forward along hinge margin. Right valved with broadly grooved posterior cardinal of moderate strength; median triangular, bevelled, rather moderately grooved; anterior tooth entire, parallel to lunular margin. Pallial sinus short, truncated, ascending. Valve margins crenate.

<==Tawera Marwick 1927 M27
    |--*T. spissa (Deshayes 1835) M27 (see below for synonymy)
    |--T. assimilis (Hutton 1873) [=Chione assimilis, Cytherea assimilis, Macrocallista assimilis] M27
    |--T. bartrumi Marwick 1927 M27
    |--T. carri Marwick 1927 M27
    |--T. errans Marwick 1927 M27
    |--T. gallinula [=Venus gallinula] M27
    |--T. lagopus M54
    |--T. marshalli Marwick 1927 [=Chione (Ventricoloidea) marshalli Cossmann in Marshall 1917 (n. n.)] M27
    |--T. propinqua [=Chamelea propinqua] M27
    |--T. subsulcata (Suter 1905) M27 (see below for synonymy)
    `--T. wanganuiensis Marwick 1927 M27

*Tawera spissa (Deshayes 1835) M27 [=Venus spissa M27, Chione (Chamelea) spissa M27, Chioneryx spissa F27; incl. Venus crassa Quoy & Gaimard 1835 M27, Chione gibbosa Hutton 1873 M27, V. mesodesma Quoy & Gaimard 1835 M27, Chione (Chamelea) mesodesma M27]

Tawera subsulcata
(Suter 1905) M27 [=Chione subsulcata M27, Chioneryx subsulcata F27, Cytherea (Circomphalus) subsulcata M27]

*Type species of generic name indicated

REFERENCES

[F27] Finlay, H. J. 1927. A further commentary on New Zealand molluscan systematics. Transactions and Proceedings of the New Zealand Institute 57: 320-485.

[M54] Macpherson, J. H. 1954. Molluscs (sea shells and snails). In The Archipelago of the Recherche (J. M. Willis, ed.) pp. 55-63. Australian Geographical Society: Melbourne.

[M27] Marwick, J. 1927. The Veneridae of New Zealand. Transactions and Proceedings of the New Zealand Institute 57: 567-636.

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