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Figure 1


Figure 2


Figure 3.

Species Name: Gyrosigma hummii Hustedt
Common Name: None
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Protista Bacillariophyta Bacillariophyceae - - Gyrosigma

    Species Description

    In the original description, valves are slightly sigmoid, broadly linear to lanceolate with obtuse obliquely rounded ends (Fig. 1, holotype, from Hustedt 1955; and Fig. 2, entire valve, SEM). The raphe is sigmoid with a narrow axial area and a small rhomboid central area. The central raphe ends are slightly deflected to the same side and do not overlap (Fig.3), whereas the holotype drawing shows the raphe ends not bent (Fig. 1). Striae are composed of areolae with slotted exteriors (Fig. 3), numbering 13-15 per 10µm for transapical, and about 12-13 per 10µm longitudinal, increasing to about 16-17 in 10µm near the margin.  The valves are 120-190µm long and 27-30µm wide in the original description, but the few examples seen were 112-126µm in length and 25-26µm in width. It is closely related to G. simile (Grun.) Boyer, and the distinction between the two is not nearly as evident as Hustedt (1955) indicates

    The species is distinctive because of its length:width ratio of 4 to 6; but it has been seen only in the northern IRL and the Banana River. Navarro (1982) also reports it as rare.

  2. HABITAT AND DISTRIBUTION

    No information is available at this time

  3. LIFE HISTORY AND POPULATION BIOLOGY

    No information is available at this time

  4. PHYSICAL TOLERANCES

    No information is available at this time

  5. COMMUNITY ECOLOGY

    No information is available at this time

  6. ADDITIONAL INFORMATION

    No information is available at this time

  7. REFERENCES

    Hustedt F. 1955. Marine littoral diatoms of Beaufort, North Carolina. Bull Duke Univ Mar Sta 6: 1-67.

    Navarro JN. 1982. Marine diatoms associated with mangrove prop roots in the Indian River, Florida, U.S.A. Biblio Phycol 61: 1-151.

Unless otherwise noted, all images and text by PE Hargraves
Editing and page maintenance by LH Sweat
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Page last updated: 22 September 2015

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