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LM image scalebar = 10 µm = 38 pixels
SEM image scalebar = 5 µm
Observations
| Observations: | Sarah Spaulding and Rhea Esposito |
|---|---|
| Length: | 20-39 micrometers |
| Width: | 7-12 micrometers |
| Striae: | 14-16 per 10 micrometers at the center; 16-18 per 10 micrometers at the ends |
Description:
Valves elliptical to elliptical-lanceolate with rounded endings that are slightly rostrate. Axial area present, widening towards the center. Central area varying from elliptic to an acute-angled sub-fascia. A solitary stigma is present in the central area. Raphe straight; median and terminal raphe endings hooked in the opposite direction of the stigma. Striae radiate throughout, becoming more widely spaced in the central portion of the valve. The valve shape of this species is similar to L. muticopsis, but the size and striae spacing is more similar to L. cohnii. We suggest that this form is a new variety of L. cohnii.
| Morphology: | Naviculoid |
|---|---|
| Distribution: | South Victorialand endemic |
Autecology:
Notes:
Previously referred to as L. cohnii var. #1 (Esposito et al. 2008), this taxon was long thought to be an initial cell of an unknown diatom due to its large size and scarcity. However, since a large population was found in a cryoconite hole on the Commonwealth Glacier, it is possible that this species is not rare, and is instead occasionally transported from the glaciers into streams. In valve dimensions and outline, L. bradyi most resembles L. wulffii (Peterson) Levkov et al. (2013) which is an arctic species reported from Canada and Russia. However, L. wulffii has a very narrow rectangular to bow-tie shaped central area, while the central area in L. bradyi is broadly rectangular or elliptic. The shortened striae in L. wulffii are composed of 1–2(3) areolae (Levkov et al. 2013), while the shortened striae in L. bradyi may number 3–5 on the side of the isolated pore. Striae in L. bradyi terminate more irregularly in the axial area than L. wulffii, which exhibits straight striae. Lastly, apices in L. bradyi are subcapitate at the largest sizes and become rostrate as valves become smaller. Apices in L. wulffii remain subcapitate, contricted where the apices meet the body, throughout the size range as illustrated in Levkov et al. (2013). These differences, along with opposite polar distributions, are sufficient to separate these two species from each other. Luticola magellanica (Frenguelli) Levkov et al. (2013), described from Tierra del Fuego, is also similar in outline, but has denser striae (14–18 in 10 ?m) and n 753 ever develops constrictions at the apices; the apices are rounded. In Antarctica, L. vermeulenii is similar in valve length and width range (24–50 ?m, 9.5– 14.0 ?m), though slightly longer than our observed population of L. bradyi. Luticola vermeulenii also has denser striae (14–17 in 10 ?m vs. 17–21 in 10 ?m) and differs in valve outline, never forming constrictions at the apices like the subcapitate endings in L. bradyi at the upper size ranges. In the McMurdo Sound Region, L. bradyi is most similar to L. cryophila and L. laeta, which are also common cryoconite species (Stanish et al. 2013). However, most differences between these two species are found with respect to valve size. L. bradyi is generally much larger is length and width compared to L. cryophila and L. laeta, as well as most other Luticola. Lastly, the apices of L. bradyi are broadly rostrate, becoming subcapitate at larger size ranges. This differs from the apices of L. laeta, which are always more narrow and never become constricted where they meet the central area.
McMurdo Dry Valleys Waterbodies with Luticola bradyi
- Aiken Creek
- Bowles Creek
- Canada Stream
- Commonwealth Stream
- Delta Stream
- Green Creek
- Harnish Creek Tributary
- Huey Creek
- Lake Fryxell
- Lost Seal Stream
- Von Guerard Stream
Original Type Description
| Author: | Kohler et al. 2015 |
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| Length: | |
| Width: | |
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Original Description:
New combination
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Citations
Index Nominum Algarum (INA):
- If an INA link is available, it will be shown above
- The INA is a bibliographic reference "card file" for algal taxonomy, containing nearly 200,000 names of algae (in the broad sense).
