Luticola elegans

Taxon ID: 387
Author: West & West 1911   
Basionym: Navicula murrayi var. elegans
Synonym:

 

Images

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LM image scalebar = 10 µm = 72 pixels      SEM image scalebar = 5 µm  

 

Observations

Observations: Tyler Kohler and Katerina Kopalová
Length: 12.9–35.8 ?m
Width: 6.4–9.5 ?m
Striae: 16–20 in 10 ?m

Description:

Valve lanceolate to elliptical-lanceolate with capitate to sub-capitate apices in the middle size ranges, becoming rostrate in smaller and greater size range. Valve dimensions: length 12.9–35.8 ?m, width 6.4–9.5 ?m. Central area broadly rectangular to round, axial area wide throughout the entire valve opening slightly towards the central area. Raphe branches straight, both proximal and distal raphe endings deflected away from the isolated pore. Striae radiate throughout, 16–20 in 10 ?m, with 3–4 areolae per stria (n=10).

Morphology: Naviculoid
Distribution: Antarctic endemic

Autecology:

 

Notes:

Like many Luticola taxa from the McMurdo Sound Region, L. elegans is a diatom with a complicated history. West & West (1911) described Navicula murrayi var. elegans from presumably one large valve measuring 31 ?m long, 8.1 ?m wide, and with 15 striae per 10 ?m. Later, Ko-Bayashi (1963) published images of what may be this diatom under the name N. muticopsis var. elegans, and has been seldom reported since. As discussed above, Levkov et al. (2013) argued that the illustration of L. murrayi is based off the initial cells of a previously unknown capitate species, though they do not discuss N. murrayi var. elegans, whose figure is adjacent to that of N. murrayi. The species reported in Levkov et al. (2013) as L. murrayi has a length range of 16–35 ?m, width 6.5–8.5 ?m, and 15–17 striae in 10 ?m, with initial cells reported up to 45 ?m long and 12 ?m wide. We are confident that species described as L. murrayi in Levkov et al. (2013) is identical to the species found in our recent material, which we here elevate to species as L. elegans. The upper size range of this species may be confused with L. murrayi, and is probably why this species was initially described as a variety. However, when a size diminution series of each species is observed and compared, they can be easily separated into two morphologically distinct groups. The morphology of L. elegans includes strongly capitate ends at intermediate size range, becoming more rostrate at the upper and lower size ranges. Luticola murrayi on the other hand never becomes capitate nor rostrate at its apices either at upper or lower size ranges, and remains obtuse and rounded in all cells. Furthermore, the center of the valve remains rounded and convex in L. elegans, conforming well to the description of Navicula murrayi var. elegans reported by West & West (1911), while the widest part of L. murrayi is directly in the center of the cell. Lastly, the central stauros in L. elegans can be rounded (though it can also be rectangular) unlike L. murrayi, and is clearly illustrated in the original West & West (1911) illustration. Luticola elegans may be confused with L. austroatlantica, which is very similar in valve outline at intermediate side ranges. However, L. austroatlantica is more narrow in width (5.6–8.2 ?m vs. 6.4–9.5 ?m), and has fewer areolae per striae (2–3 vs. 3–4). Luticola elegans additionally is less constricted between the capitate apices and the valve center compared to L. austroatlantica, and apices are generally wider. At the upper size range, L. elegans is more rostrate, while L. austroatlantica is more capitate. Conversly, L. austroatlantica is more rostrate at lower size ranges, while L. elegans has sub-capitate apices even at the smallest sizes. Luticola elegans may also resemble L. gaussii, and the two are often found in the same habitats, especially at Cape Royds. However, L. gaussii differs in valve outline, having a more rounded central portion while L. elegans is more elongate. In general, L. gaussii is wider and shorter than L. elegans, and L. gaussii additionally has more dense (19–23 in 10 ?m), patterned striae organized into three longitudinal rows not present in L. elegans.

 

McMurdo Dry Valleys Waterbodies with Luticola elegans

  • Blue Lake
  • Bowles Creek
  • Canada Stream
  • Clear Lake
  • Hughes Glacier Pond
  • Labyrinth Pond
  • Little Sharpe
  • Lost Seal Stream
  • McMurdo Hut Ridge
  • Picture Pond
  • Pond by Blue Lake
  • Pond by Clear Lake
  • Pond North of Rookery
  • Pond South of Nussbaum Riegel
  • Spaulding Pond
  • Upland Pond
  • Von Guerard Stream
  • Wharton Creek

Original Type Description

Author: West & West 1911
Length: 31 µm
Width: 8.1 µm
Striae: 15 in 10 µm

Original Description:

Minor, polis valvae angustioribus, productis et subcapitatis; striis 15 in 10 µ.

 

New combination

Author: Kohler & Kopalová 2015

 

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).

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