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Pleurosigma amarum S.R.Stidolph
In this section
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Factsheets
- Achnanthes crosbyana
- Actinella aotearoaia
- Caloneis clevei var. carteriana
- Cavernosa kapitiana
- Dimerogramma maculatum fo. mercuryensis
- Entomoneis wilkinsonia
- Eolimna krummensis
- Eunophora berggrenii
- Eunotia sudetica var. hamuranaensis
- Fallacia vittata var. rotoehuensis
- Fragilariforma cassieae
- Fragilariforma rakiuriensis
- Frankophila biggsii
- Frustulia aotearoa
- Frustulia cassieae
- Frustulia gondwana
- Frustulia maoriana
- Gyrosigma foxtonia
- Gyrosigma sterrenburgii
- Hamatusia reediana
- Navicula barberiana
- Navicula cassieana
- Navicula tairuaensis
- Pinnularia barberiana
- Pinnularia barberiana var. opouraensis
- Pinnularia chapmaniana
- Pinnularia opouraensis
- Pinnularia segariana
- Pinnularia woodiana
- Planothidium victori
- Pleurosigma amarum
- Sellaphora styxii
- Surirella rattrayi f. acuminata
- Tabularia variostriata
- Thalassiosira hasleae
Known distribution
New Zealand
Kapiti Island: Okupe Lagoon, Lat. 40°50'S, Long. 174°56'E; Napier: Westshore, Lat. 39°28'S, Long. 176°52'E; Purimu Creek, Lat. 39°30'S, Long. 176°52'E; Miranda: Lat. 37°10'S, Long. 175°19'E.
Etymology
Meaning "brackish of habitat".
Description
Valve sigmoid, valve face flat up to about a quarter of distance from apex then vaulted towards narrowly rounded apices. Length of valve 253.6-360.0 µm, width 28.0-31.7 µm. Axial area narrow, central area small, conspicuous and orbicular; not rotated. Axial rib of single curvature, approximately central but displaced to convex valve margin near apices. Raphe angle +5/+7°. Helictoglossa conspicuous, terminal areas rather obscure, displaced slightly to concave side of axial rib. Striae transapical and oblique, crossing at 61-64°. Transapical and oblique striae 20-21 in 10 µm. Colour in standardised darkfield: peacock blue.
Notes
Funding from TFBIS (Terrestrial and Freshwater Biodiversity Information System), administered by the New Zealand Department of Conservation, is gratefully acknowledged.
Reference
Stidolph SR 1992. Observations and remarks on the morphology and taxonomy of the diatom genera Gyrosigma Hassall and Pleurosigma W. Smith III. Gyrosigma sterrenburgii sp. nov., and Pleurosigma amara sp. nov. Diatom Research 7: 345-366.