O. De Clerck

Systematic reassessment of the red algal genus Phyllymenia (Halymeniaceae, Rhodophyta)

A systematic reassessment of the sole representative of the South African genus Phyllymenia, P. belangeri, indicates a lack of clear-cut diagnostic characters to separate it from Grateloupia. The morphology of the auxiliary cell ampullae, widely regarded as a key generic character in the Halymeniaceae, is almost identical in both genera. The autapomorphic character that has traditionally separated Phyllymenia from Grateloupia is the formation of pronounced lateral cytoplasmic protuberances on inner cortical cells. However, the establishment of protuberances is correlated with the presence of large intercellular spaces between neighbouring cortical cell files, coupled with narrow intercalary cortical cells. Thus, in order to establish secondary pit connections to more distant neighbouring cells, cortical cell protuberances may have become more prominent in P. belangeri than in species of Grateloupia with smaller intercellular spaces. Phylogenetic analyses of chloroplast-encoded rbcL sequences for a dataset including four representatives of P. belangeri and 32 other species, currently placed in Grateloupia or Prionitis, resolve (with high support) P. belangeri as a sister taxon of G. longifolia from South Africa. Based on morphological and molecular evidence, it is therefore proposed that Phyllymenia be reduced to a synonym of Grateloupia.

An Updated and Annotated List of Marine Brown Algae (Phaeophyceae) of the Caribbean Coast of the Republic of Panama

Abstract Thirty-six taxa of brown macroalgae (Phaeophyceae) are reported for the Caribbean coast of the Republic of Panama including 16 new records. Most of the species diversity is restricted to two families, Dictyotaceae and Sargassaceae. This updated list represents an increase in known algal diversity for Panama of approximately 80%, but diversity is probably underestimated as revealed by comparison to the Colombian and Costa Rican floras which harbor many species not yet recorded in the marine flora of Panama. In total species diversity, Panamas brown algal flora is considerably less diverse than Caribbean Colombia but comparable to Caribbean Costa Rica. In addition to presenting a comprehensive species list, we propose the synonymy of Dictyota pfaffii Schnetter with D. friabilis Setchell and D. jamaicensis W. R. Taylor with D. crenulata J. Agardh and discuss other taxonomic problems regarding the Caribbean Dictyotales.

Schimmelmannia elegans (Gloiosiphoniaceae, Rhodophyta): South Africa's first introduced seaweed?

Abstract Although there are a number of records of recently introduced marine animals in South African waters, there has never been good evidence of a seaweed introduction. Schimmelmannia elegans, a red alga previously only known from Tristan da Cunha and Nightingale Island, is reported for the first time for South Africa. The plants were found growing in the Kelp Tank of the Two Oceans Aquarium in Cape Town. The morphology and reproduction of the specimens are described in detail and agree in all aspects with the original account of S. elegans. Several hypotheses on the alTival of this newcomer along the South African coast are discussed: previously overlooked, present as a different life history stage, or recently introduced. Of these, recent introduction seems the most plausible. In this context, the spread and potential ecological significanceof an introduced seaweed species are discussed.

Twenty marine benthic Algae new to South Africa, with emphasis on the flora of Kwazulu-Natal

Abstract A total of 20 new records of benthic marine algae has been added to the flora of South Africa, consisting of 6 taxa of Phaeophyta and 14 Rhodophyta. Most species have a pantropical or Indo-Pacific distribution and are generally known from several localities in the Indian Ocean (e.g. Asteronema breviarticulatum, Ceramium cingulatum, Dictyota cervicornis, D. ciliolata, Euptilota fergusonii, Galaxaura rugosa, Halymenia durvillei, Phacelocarpus tristichus). Others are only known from a limited number of reports scattered within the Indo-Pacific region (Balliella crouanioides, Gibsmithia hawaiiensis, Predaea weldii, Hypoglossum minimum), possibly due to their subtidal habitat or small size. Apart from those algae with a large distribution range, some species show a distinctive southern Australian–South African distribution pattern (Carpopeltis phyllophora, Plocamium mertensii). Only Digeneopsis subopaca, originally described from Mozambique, appears to represent a local endemic species.

Ptilophora leliaertii and Ptilophora coppejansii, two new species of Gelidiales (Rhodophyta) from South Africa

Ptilophora leliaertii Tronchin et De Clerck sp. nov. and Ptilophora coppejansii Tronchin et De Clerck sp. nov. are described from Protea Banks reef situated off the southern coast of the KwaZulu-Natal Province in South Africa. They have thus far been collected only on this reef system. Ptilophora leliaertii is distinguishable by its compound pinnate branching and the concave nature of its flattened branches. Ptilophora coppejansii is distinguishable by short, closely spaced pinnae in its distal parts, arising from irregularly arranged indeterminate branches with broad flexuous alae and a distinct midrib. Analyses of rbcL and LSU gene sequences resolve both species as distinct, well-supported taxa, with P. coppejansii sister to Ptilophora diversifolia (Suhr) Papenfuss, and P. leliaertii sister to Ptilophora helenae (Dickinson) R. Norris. The reinstatement of P. helenae, a species recently placed in synonymy with Ptilophora pectinata (A. Gepp & E. Gepp) R. Norris from Australia, is proposed here based on molecular, morphological and biogeographical evidence.

Morphological and taxonomic studies of Gracilaria and Gracilariopsis species (Gracilariales, Rhodophyta) from South Africa

Southern Africa has an extremely rich and diverse seaweed flora with a wide variety of marine habitats. Increased commercial interest in these seaweed resources has been the stimulus for biodiversity studies. The Gracilariaceae (Rhodophyta) has emerged as one of the families that possess economic potential as a source of agar and as a potential feed for abalone. A lack of knowledge concerning the taxonomic status of many members of this family is a concern. Gross morphological characters have been the main means of identification and incorrect applications have led to a number of misidentifications. Consequently, a comprehensive reappraisal and revision of these species was carried out. The species count for the South African Gracilariaceae is now two Gracilariopsis species, and nine Gracilaria species. Gracilaria crassa has been reduced to a synonym of G. canaliculata. It is believed that G. foliifera was erroneously identified and specimens in South Africa referred to as G. millardetii and G. protea are assigned to G. corticata. South African Gracilariopsis, previously referred to as Gs. lemaneiformis, is confirmed to be conspecific with European Gs. longissima. This species occurs along the west and south coasts of South Africa, co-existing in a few habitats with G. gracilis. The taxonomic identity of G. vieillardii specimens from South Africa and the differentiation of G. canaliculata and G. salicornia has been confirmed based on morphology. Three species of Gracilaria (G. aculeata, G. beckeri and G. capensis) are endemic or near endemic to the South African coast, and a fourth species, G. denticulata is localised in southeast Africa.

The change in macroalgal assemblages through the Saldanha Bay/Langebaan Lagoon ecosystem (South Africa)

Abstract Saldanha Bay and Langebaan Lagoon form together one of the few sheltered habitats within the Benguela Marine Province; a wide gradient in environmental factors is found here. The West Coast National Park was established to protect this unique ecosystem, but at the same time an industrially expanding harbour marks this area. In an effort to understand the biological composition of the Saldanha/Langebaan ecosystem, the intertidal macroalgal assemblages were studied in relation to the relatively well-known South African West Coast flora. Three distinct floral entities were identified using various analytical techniques (similarity coefficients, CCA and TWINSPAN): (i) the species poor, though distinct, salt marshes; (ii) the Lagoon sites; and (iii) the Bay and West Coast sites. The transition between the latter two is located at the mouth of the Lagoon. The species richness of the Bay/West Coast entity is larger than in the Lagoon. The change in algal composition can be explained in terms of the environmental variables of which wave exposure is the most significant. Other important environmental parameters are water surface temperature and salinity, which were found to be negatively correlated with wave exposure. Biogeographical affinities of the different algal entities of the Bay/Lagoon system were also determined in relation to the entire South African shoreline. The Bay/West Coast entity supports a typical West Coast flora, with some noticeable effects of uplift of subtidal species into the infralittoral fringe and morphological variation in less exposed areas. The algal flora of the Lagoon is also dominated by West Coast species, but is typified by species characteristic of sheltered habitats, and with a number of species which otherwise only occur on the geographically distant South Coast (east of Cape Agulhas). The algae from the salt marshes occur widely in tropical mangroves and warm temperate salt marshes.

New records of the Chlorophyta from South Africa, with the emphasis on the marine benthic flora of KwaZulu-Natal

Eleven species of marine Chlorophyta that have not previously been reported for South Africa have been found on the coast of Kwazulu-Natal: Avrainvillea cf. riukiuensis Yamada; Boodleopsis pusilla (Collins) W.R. Taylor, Joly & Bernatowicz; Bornetella nitida Sonder; Caulerpa serrulata (Forsskal) J. Agardh; C. taxifolia (Vahl) C. Agardh; Chaetomorpha spiralis Okamura; Cladophoropsis sundanensis Reinbold; Halimeda gracilis Harvey ex J. Agardh; Neomeris annulata Dickie; Neomeris bilimbata Koster; Udotea indica A. Gepp & E. Gepp. Three of the above genera (Avrainvillea, Boodleopsis and Bornetella) are new for South Africa. Descriptions and illustrations are provided for each species. Furthermore the species are compared with other similar species in the area and their ecology and biogeography are briefly discussed.

First freshwater coralline alga and the role of local features in a major biome transition

Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

New Records of the Green-Algal Genus Rhipiliopsis (Udoteaceae, Caulerpales) from Papua New Guinea and the Seychelles Islands, Including the Description of Rhipiliopsis papuensis Coppejans, De Clerck et Leliaert, sp. nov.

Abstract A new monostromatic species of Rhipiliopsis, R. papuensis, is described from shaded subtidal habitats on the south coast of Papua New Guinea. Closely related to R. novae-caledoniae Farghaly et Denizot, it differs in having a basally corticated stipe, a lack of wall thickenings above the dichotomies of the blade siphons, and by its very regularly sinuous siphons that are linked laterally by evenly spaced cohesion papillae. New distribution records are made of R. gracilis Kraft, from the same locality as R. papuensis, and of R. echinocaulos (Cribb) Farghaly and R. madagascariensis Farghaly et Denizot from the Seychelles Islands in the western Indian Ocean. A key to the monostromatic species of Rhipiliopsis is presented.