Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
| | Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990) |
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  (Pl. 5j): GS9959, J40/f6610, South Branch, Waihao River near "Pentland Hills", Bortonian (GNS) |
 (Pl. 5l): GS9959, J40/f6610, South Branch, Waihao River near "Pentland Hills", Bortonian (GNS) |
Beu & Maxwell (1990): Chapter 7; p. 104; pl. 5 j, l.
Classification: Tellinidae: Tellininae
Description: Rather small for family (length 15-25 mm), very elongate, beaks posterior to middle, left valve more inflated than right. Anterodorsal margin long, straight; posterodorsal margin much shorter, junction with backwards-sloping posterior end obtusely angled. Anterior margin narrowly convex, ventral margin broadly convex except for slight concavity near posterior end, accentuating the short, right-twisted rostrum formed at junction with posterior margin. Umbonal ridge well marked, defining a narrow posterior area; left valve with additional weaker ridge running to middle of posterior margin. Sculpture discrepant, considerably more prominent in right valve, particularly over distal half of shell, consisting of narrow, low commarginal ridges. Hinge very narrow, left valve with low anterior and posterior laterals scarcely differentiated from shell margin, a narrowly triangular, bifid median cardinal tooth and a very thin posterior cardinal tooth. Right valve with long, narrow anterior and posterior lateral teeth separated from margins by narrow sockets, a narrow anterior cardinal tooth and a narrowly triangular, bifid posterior cardinal tooth. Pallial sinus extending to near middle of shell, rounded, ventral limb only partly confluent with pallial line.
Comparison: This new species is readily distinguished from other New Zealand tellinids by its rather small size, its very elongate shape, its narrowly rostrate posterior end, and its markedly discrepant sculpture. Several other New Zealand tellinids have been assigned to the warm-water genus Tellinella, but they differ in shape, pallial and muscle characters from typical members of the genus and are here included in Serratina. The species described here is the only local species that can be assigned to Tellinella with any confidence.
Distribution: Bortonian, South Branch, Waihao River near "Pentland Hills"; Opihi River, South Canterbury; Kakahu; Ten Mile Creek, Westland. Moderately common at the first locality, less so at the others.
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)