Phaeophyta, Brown Algae
Lobophora variegata (Lamouroux) Womersley
Phaeophyta, Order: Dictyotales; Family: Dictyotaceae.
The generic name of the genus, Lobophora, means ‘carrier of lobes’, referring to the thallus that resembles a kidney- shaped lobe. Variegata means ‘multi-shaped’, hinting at the variance in growth shapes of the species.
The Lobophora has a flattened thallus shaped like a fan. It attaches to rocks loosely and to the substrate through numerous rhizoids. The flattened thallus is more common in the Eastern Mediterranean. In other places, two varieties are common, the flattened and the wrinkled. The form of growth may be the result of abiotic conditions in the habitat and the eating habits of local herbivores.
The diameter of the Lobophora variegata’s thallus is usually
not more than 3 cm. Sometimes, it may be found in large colonies measuring several dozen centimeters.
The Lobophora’s thallus is brown, sometimes with dark spots that form concentric circles coloured brownish-yellow. There is a certain variance in colour between individuals, perhaps the result of genetics, age, reproductive condition or available lighting.
The algal dark colour blends with that of the rock, making it hard to identify the alga with an unskilled eye. The Lobophora resembles a dark, brown-shaded fan-like skin.
The Lobophora grows in potholes, usually in shady corners. It is very common at depths of 10-15 m. Evidence has been reported of deep sea presence, though, even at depths of over 30 m.
Biology and reproduction
The Lobophora’s thallus is comprised of eight or nine layers of cells. Sporangia are arranged in groups of four or eight, located on the upper part of the thallus and covered with a skin. Development is through a row of apical cells as in the Stypopodium.
Seasonality and distribution
The Lobophora can be found along the shore throughout the year, and individuals seem to be perennial. The species geographical distribution is quite extensive: it can be found in the Mediterranean, along the coasts of the Atlantic Ocean, the Indian Ocean and the Pacific Ocean.
This is apparently the only species reported in the Mediterranean. It also appears under the synonym, Zonaria variegata (C. Agardh) Greville.