Phaeophyta, Brown Algae
Taonia atomaria (Woodward) J. Agardh
Phaeophyta, Order: Dictyotales; Family: Dictyotaceae.
The name Taonia, was bestowed upon the genus due to the other species of Taonia, which are rounder and more colourful than the above species, and resemble the ‘tail of the peacock’. The spots referred to in the scientific name of the species, atomaria (dotted), refers to the clusters of reproductive organs found in the thallus.
The Taonia atomaria is a flat brown alga that splits into uneven strands. The strands are usually unequal in width, as well, but often uniformity in width can be found in the same individual. The edges of the strands are dented. Along
them, dark lateral lines are straight or zig-zagged, continuous or unconnected. These lateral lines are actually the location of hairs and reproductive cells. The Taonia clings to the substrate using a holdfast and rhizoids. The branching is irregular, causing the alga to widen.
The Taonia’s strands grow to a length of 30 cm, and their width ranges between 1 mm to 2-3 mm. Its width is usually 1-2 mm, but may reach 5 mm.
The Taonia is dark brown at the base and gets lighter towards its edges. The shades of brown range from greenish-brown to light brown, according to the algal age and the lighting in the habitat.
There is a certain resemblance between the Taonia and the Padina. Mature and deteriorated Padina individuals sometimes resemble Taonia. The Taonia, however, is unique for its lateral jagged lines and the fact that it does not calcify.
The Taonia grows below the tidal line, in places unexposed to air. It is often found in potholes.
Biology and reproduction
The Taonia, like other family members, has visually similar sexual and asexual generations. The asexual generation is more common, and seems to be perennial. The thallus regenerates each year from the same base. The sexual generation is rarer and harder to find. The Taonia may not
Taonia atomaria - cluster of female reproductive cells.
perform regular heteromorphic generation in the Eastern Mediterranean, and the germinating of diploid spores appears to be what generates the diploid generation.
Seasonality and distribution
The Taonia atomaria is not a common alga, but it can be found in the sea. Chances of locating it each year in the same place are high. Most individuals of Taonia atomaria were collected on shore in winter and spring. The alga appears either in groups or as single individuals. It can be found along Europe’s northern coasts and in the Indian Ocean.
The Taonia atomaria seems to be the only species found in the region.