Algae · Brown algae · Marine Life · South Africa

Lightning seaweed (Oerstedtia scalaris)

Specimen of 'lightning seaweed' on the rocky shores at low tide. Unknown location, South Africa (2021). Plants dark brown to yellowish-brown, with tough rather than rubbery texture, comprising a prominent, woody, conical holdfast bearing one or more main axes that, in turn, bear primary lateral branches with distichous, alternating arrangement of leaves - rarely, second… Continue reading Lightning seaweed (Oerstedtia scalaris)

Cnidarians · Hydrozoans · Marine Life · South Africa

Indo-Pacific man-of-war (Physalia utriculus)

Bluebottle washed on the rocks. Cape Agulhas, Western Cape (2020) - iNaturalist Unmistakable with its inflated blue-green float and long trailing tentacles. Float 50 mm long, tentacles up to 10 m long, but contracting to about 30 cm. Floats on the surface of the sea and is vulnerable to being cast ashore by onshore winds.… Continue reading Indo-Pacific man-of-war (Physalia utriculus)

Algae · Brown algae · Marine Life

Different-leafed sargassum (Sargassum incisifolium)

Specimen of sargassum found in a rock crevice. Cape Agulhas, Western Cape (2020) - iNaturalist Bushy yellow-brown plants with a triangular stem, small air-floats and two types of blades, attached to the substrate by a large conical holdfast that bears one or several strong perennial stems. The lower 'leaves' are oval and marginally toothed, while… Continue reading Different-leafed sargassum (Sargassum incisifolium)

Limpets · Marine Life

Rayed limpet (Helcion pruinosus)

Rayed limpet with iridescent green spots and rays in a shallow rock pool. Port Alfred, Eastern Cape (2021) - iNaturalist Shell low, fragile and oval. Apex about one-third from the front margin. Surface smooth, pale brown, shot with beautiful iridescent green spots and rays. About 25 mm. Hides beneath low-shore boulders during the day, and… Continue reading Rayed limpet (Helcion pruinosus)

Algae · Brown algae · Marine Life

Starred cushion (Iyengaria stellata)

Star cushion alga in a rock pool. Cape Agulhas, Western Cape (2020) - iNaturalist Plants yellow-brown, forming thin, globose cushions of compacted branching tubes, irregularly furrowed and convoluted. Surface covered with knobbly protuberances. Thalli at first solid but older plants becoming hollow in the center. Up to 10 cm in diameter and 3 to 4… Continue reading Starred cushion (Iyengaria stellata)

Barnacles · Marine Life

Toothed barnacle (Chthamalus dentatus)

Toothed barnacles on a rock face. Cape Agulhas, Western Cape (2020) - iNaturalist A small, flat, dirty-white barnacle with a membranous (not calcareous) base. The projecting, finger-like ridges on the six shell plates produce the characteristic star-shaped outline. Between 5 - 10 mm. Common in the upper intertidal, especially on the South and East coasts.… Continue reading Toothed barnacle (Chthamalus dentatus)

Marine Life · Sedentaria · Worms

Blue coral-worm (Pomatoleios kraussii)

Blue coral-worm reef. Port St Johns, Wild Coast, Eastern Cape (2021). Also known as Spirobranchus kraussii. Gregarious, building massive blue colonies of interwoven tubes which are calcareous (a feature of the family Serpulidae). Head with two rows of feathery branches and a stalked operculum that has two pointed 'wings' and a flat calcareous cap. Worms… Continue reading Blue coral-worm (Pomatoleios kraussii)

Limpets · Marine Life

Goat’s eye limpet (Cymbula oculus)

Goat's eye limpet with Ralfsia covering its shell and a little blurry isopod. Mosselbaai, Western Cape (2022). Shell flat, dull brown above, with above 10 major ribs that project from the margin. Interior with a broad black margin and a pink-brown center. Juveniles are yellow, with iridescent green flecks. About 100 mm. Lives in the… Continue reading Goat’s eye limpet (Cymbula oculus)

Algae · Brown algae · Encrusting algae · Marine Life · South Africa

Ralfsia (Ralfsia verrucosa)

Details of the concentric rings of Ralfsia, with some missing patches (probably grazed). Cape Agulhas, Western Cape (2020). Ralfsia verrucosa can be considered an inactive taxon by some (for example, on iNaturalist). It is then replaced by Pseudoralfsia verrucosa. Forms flat patches or irregular, concentric rings. Brown, grading to khaki, with pale edges. About 1… Continue reading Ralfsia (Ralfsia verrucosa)

Algae · Brown algae · Marine Life

Dead-man’s finger (Splachnidium rugosum)

Wrinkling dead-man's fingers in a rock crevice. Hondeklipbaai, Northern Cape (2020) - iNaturalist Swollen yellow-brown, finger-like bladders, filled with thick, clear slimy mucilage, turgid when wet and becoming withered and wrinkled when dry. The main stipe is swollen with many similarly shaped side branches which are constricted at their point of origin and rounded at… Continue reading Dead-man’s finger (Splachnidium rugosum)