Biology:Thyasira motutaraensis
| Thyasira motutaraensis | |
|---|---|
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| Holotype from Auckland War Memorial Museum | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Lucinida |
| Family: | Thyasiridae |
| Genus: | Thyasira |
| Species: | †T. motutaraensis
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| Binomial name | |
| †Thyasira motutaraensis A. W. B. Powell, 1935
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| Synonyms[1][2] | |
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Thyasira motutaraensis is an extinct species of bivalve, a marine mollusc, in the family Thyasiridae.[2] Fossils of the species date to early Miocene strata of the west coast of the Auckland Region, New Zealand.
Description
In the original description, Powell described the species as follows:
Shell small, triangulate, higher than wide, equivalve, moderately inflated and almost equilateral. Beaks about central, small, directed forwards and incurved at tips. Anterior end sharply descending, slightly concave, with a moderately long shallowly excavated lunule which is margined by a furrow running from near the beaks to the margin. On the posterior end there are two strong, slightly divergent furrows which are close to the posterior dorsal margin and extend from near the beaks to the margin. The ridges associated with these furrows are angular on their upper edges. Basal margin convex. Surface smooth except for microscopic concentric growth lines.[3]
The holotype of the species measures 7.4 mm (0.29 in) in height, 6.5 mm (0.26 in) in width, and has a thickness of 4.75 mm (0.187 in) when measuring both valves.[3] The species can be differentiated from T. marwicki due to being higher than it is more, more angular when viewed from above, being almost equilateral, and by having an extra radial furrow bordering its lunule, and from T. bartrumi due to its having a less lunule and by having a furrow border.[3]
Taxonomy
The species was first described by A. W. B. Powell in 1935 as Thyasira (Prothyasira) motutaraensis.[3] Its currently accepted name is Thyasira motutaraensis, without a subgenus.[4][2] The holotype was collected at an unknown date prior to 1935 from between Powell Bay and Bartrum Bay, approximately 2 km (1.2 mi) south of Muriwai, Auckland Region (then more commonly known as Motutara), and is held in the collections of Auckland War Memorial Museum.[5][1]
Distribution
This extinct marine species occurs in early Miocene strata of the Nihotupu Formation of New Zealand, on the west coast of the Waitākere Ranges of the Auckland Region, New Zealand.[5] The Powell Bay site deposits of the Nihotupu Formation in the western Waitākere Ranges are mid-bathyal 800–2,000 m (2,600–6,600 ft).[6]
Gallery
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Opposite valve of holotype -
Side view of holotype -
Side view of holotype
References
- ↑ 1.0 1.1 "Thyasira motutaraensis". Auckland War Memorial Museum. https://www.aucklandmuseum.com/discover/collections/record/228286.
- ↑ 2.0 2.1 2.2 Thyasira motutaraensis (A. W. B. Powell, 1935) †. Retrieved through: World Register of Marine Species on 19 January 2026.
- ↑ 3.0 3.1 3.2 3.3 , Wikidata Q58676576
This article incorporates text from this source, which is under a CC BY 4.0 license.
- ↑ Maxwell, P.A. (2009). "Cenozoic Mollusca". New Zealand Inventory of Biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia.. Christchurch: Canterbury University Press. p. 236. ISBN 978-1-877257-72-8.
- ↑ 5.0 5.1 , Wikidata Q135397912
- ↑ , Wikidata Q104119200
Further reading
- Fleming, Charles Alexander; Marwick, John (1966). Marwick's Illustrations of New Zealand Shells with a Checklist of New Zealand Cenozoic Mollusca. Wellington: R. E. Owen, Govt. Printer. p. 26. OCLC 955302.
Wikidata ☰ Q137816673 entry
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