Manuela I. Parente

MORPHOLOGY AND LIFE HISTORY OF SCYTOSIPHON LOMENTARIA (SCYTOSIPHONACEAE, PHAEOPHYCEAE) FROM THE AZORES1

Morphological and culture studies of Scytosiphon lomentaria (Lyngbye) Link and Microspongium gelatinosum Reinke (Scytosiphonaceae, Phaeophyceae) were undertaken on material collected on the Island of São Miguel, Azores, where both species were commonly found. Erect thalli of S. lomentaria collected in the field were up to 33 cm long and 2.3 mm wide, tubular, hollow, and commonly constricted at intervals. The plurilocular sporangia were positioned in continuous sori on the thallus surface. Ascocysts were present. In the field, M. gelatinosum formed crustose to slightly pulvinate plants, were spongy in texture, and dark brown to black in color, which were circular or irregularly spreading over several centimeters and firmly attached to the substratum. Sessile unilocular sporangia were located in sori on the crust surface. In culture S. lomentaria plurispores developed into Microspongium‐like crustose prostrate thalli that formed unilocular sporangia. Unispores developed into new erect thalli that formed plurilocular sporangia. Sexual reproduction was not observed. In culture, M. gelatinosum unispores developed into erect thalli identical with S. lomentaria. These results are similar to those reported for other areas and suggest the occurrence in the Azorean plants of a monophasic and heteromorphic life history, involving both entities studied.

LIFE HISTORY OF COLPOMENIA SINUOSA (SYCTOSIPHONACEAE, PHAEOPHYCEAE) IN THE AZORES1

Colpomenia sinuosa (Mertens ex Roth) Derbès and Solier (Scytosiphonaceae, Phaeophyceae) is a common species on the rocky intertidal shores of the Azores, where reproductive gametophytes occur throughout the year. Life‐history studies of this species were carried out in culture, and both sexual and asexual reproduction were observed. Anisogamous gametes fused to form zygotes. The zygotes gave rise to a filamentous prostrate sporophyte generation bearing unilocular sporangia, under both short‐day and long‐day conditions at 15 and 22°C, and to both unilocular and plurilocular sporangia, under the lower temperature condition. Unispores developed into gametophytes, and plurispores gave rise to filamentous sporophytes. Asexual reproduction was carried out by unfused female gametes and asexual plurispores produced from the same gametophyte. Unfused gametes developed into filamentous prostrate sporophytes producing unilocular sporangia in both culture conditions, and unispores released from the sporangia gave rise to gametophytes. Asexual plurispores from field gametophytes, under both culture conditions, developed directly into new gametophytes. The species exhibited three types of life history: a heteromorphic, diplohaplontic; a heteromorphic, monophasic (both with alternation between the erect and filamentous prostrate thalli); and a monomorphic, monophasic.

The marine algal (seaweed) flora of the Azores: additions and amendments 3

Thirteen species of benthic marine algae are reported new for the isolated mid-Atlantic Azores archipelago and five older records are confirmed. Seven (Bangia atropurpurea, Codium fragile spp. tomentosoides, Ectocarpus fasciculatus, E. siliculosus, Porphyrostromium ciliare, Ulothrix flacca and Ulvaria oxysperma) are widespread amphi-Atlantic species some of which extend in distributional range south to the Canary Islands. Cryptonemia seminervis, Ctenosiphonia hypnoides and Phyllophora sicula are known from the northeastern Atlantic Ocean only and also occur in the Canary Islands. The Azores archipelago is the western limit of distribution of Codium fragile ssp. atlanticum, Bostrychia scorpioides, Bryopsis cupressina, Erythroglossum laciniatum, Haliptilon squamatum and Phyllophora sicula, and the southern limit of C. fragile ssp. atlanticum and E. laciniatum. The tropical species Phyllodictyon anastomosans, Valonia macrophysa and Wurdemannia miniata reach their northern limit of distribution there. Asparagopsis taxiformis is now less common possibly due to competition with the non-native A. armata; subspecies of the non-native C. fragile now occur widely in the Azores. The status of Fucus vesiculosus, Ulva (Enteromorpha) clathrata and Rhizoclonium tortuosum is clarified and other species have been removed from the flora. The continuing addition of new species records for the Azores shows the archipelago to be floristically richer than other Atlantic islands except for the Canary Islands.

Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusum

Gabriel D., Schils T., Parente M.I., Draisma S.G.A., Neto A.I. and Fredericq S. 2011. Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusum. Phycologia 50: 109–121. DOI: 10.2216/09-67.1 Comparative rbcL sequence analysis indicates that the species going under the name Schizymenia dubyi in the Azores should be referred to as S. apoda. Sequences of Schizymenia specimens from China and Namibia were also identified as S. apoda, of which the type locality is the Cape Province in South Africa. Schizymenia dubyi, described from Atlantic France, is clearly a distinct species that we here report for Japan and Sicily in the Mediterranean Sea. Both Schizymenia species, along with an unreported species from Japan, are distinct from S. pacifica described from Washington, in the Pacific Coast of North America. Secondary pit connections were observed in gametophytes of S. apoda from the Azores, a previously unknown character for the Nemastomatales. Examination of type material of Nemastoma confusum indicates that this species, currently placed in the Nemastomataceae, should be transferred to the genus Platoma in the Schizymeniaceae. A morphological comparison between Platoma confusum (Kraft & John) comb. nov. with descriptions of P. cyclocolpum and P. chrysymenioides suggests that the three species are closely related.

Additions to the Marine Algal (Seaweed) Flora of the Azores

Abstract Ten species of benthic marine algae, new distribution records for the Azores achipelago, are itemised; two other species records (Heterosiphonia crispella and Laminaria ochroleuca) are confirmed for the islands. Six species (Bryopsis pennata, Cottoniella filamentosa, Dasya baillouviana, Feldmannia paradoxa, Heterosiphonia crispella and Lomentaria clavellosa) show an amphi-Atlantic distribution pattern; four (Bonnemaisonia asparagoides, Laminaria ochroleuca, Pterosphonia ardreana and Stylonema cornu-cervi) show a European-African-Mediterranean distribution pattern. The occurrence of Dudresnaya crassa, a western Atlantic warm-water species, represents an extension of its known distributional range to the east. An Ahnfeltiopsis was found which resembled A. intermedia, a species that occurs in the Atlantic Ocean to the south of the Azores.

New records of brown algae (Phaeophyta) from the Azores

The following five species of microscopic tuft-forming/encrusting brown algae (Phaeophyta) are newly recorded for the Island of São Miguel (Azores): Nemoderma tingitana Schousboe ex Bornet, Pseudolithoderma roscoffense Loiseaux (Lithodermataceae), Hecatonema terminalis (Kützing) Kylin (Punctariaceae), Compsonema saxicolum(Kuckuck) Kuckuck, and Microspongium gelatinosum Reinke (Scytosiphonaceae). The species are described, and information is presented on their ecology and distribution around the island.

Phylogenetic appraisal of the genus Platoma (Nemastomatales, Rhodophyta), including life history and morphological observations on P. cyclocolpum from the Azores.

Gabriel D., Parente M.I., Neto A.I., Raposo M., Schils T. and Fredericq S. 2010. Phylogenetic appraisal of the genus Platoma (Nemastomatales, Rhodophyta), including life history and morphological observations on P. cyclocolpum from the Azores. Phycologia 49: 2–21. DOI: 10.2216/07-99.1 The red algal genus Platoma Schmitz (Schizymeniaceae, Nemastomatales) with type Platoma cyclocolpum (Montagne) Schmitz was originally described from the Canary Islands. Life history studies were conducted on P. cyclocolpum from the Azores under 10°C/8∶16 light (L)∶dark (D), 15°C/16∶8 L∶D, and 23°C/natural daylight regimes in culture. Three nonreproductive modes of thallus development resulted from germinating carpospores: (1) a permanent crust, (2) a filiform, nonfoliose erect thallus occasionally attached by a holdfast composed of cell aggregations, and (3) a filiform, nonfoliose erect thallus has been reported previously for populations from the Canary Islands, but the latter two have not been described before. Platoma cyclocolpum is widely reported in the literature, but specimens under that name from Madagascar are identified here as Platoma chrysymenioides Gavio et al., a deepwater species first described from the northern Gulf of Mexico and now recorded for the entire gulf. Genuine P. cyclocolpum specimens from the Azores, Madeira, and the Canary Islands were sequenced for chloroplast-encoded rbcL, and phylogenetic relationships of four Platoma species are discussed. A table listing diagnostic morphological and anatomical features of Platoma species is provided.

Morphology and life history studies of Endarachne binghamiae (Scytosiphonaceae, Phaeophyta) from the Azores

First reported for the Azores in 1994, Endarachne binghamiae is commonly found throughout the year on hard substrates in the upper mid-tidal region of the exposed Azorean shores. Morphological and culture studies of this species were carried out based on material collected from six localities on the island of Sao Miguel. Erect thalli collected in the field are dorsiventrally flattened and arise from an encrusting base or small discoid holdfast. The erect blades, up to 13 cm long and 2 cm wide, are lanceolate or obovate, simple, solid and thin, gradually tapering at the base. The plurilocular sporangia lack paraphyses and are positioned in continuous sori covering most of the surface area of the blades. Reproductive plants, with plurilocular sporangia, occurred all year round. In culture, spores released from the plurilocular sporangia developed into small knot-filaments, which upon squashing exhibited a three-dimensional representation of a typical multistratose crust. These prostrate knot-filaments gave rise directly to new erect blades. No unilocular sporangia were seen and no evidence of sexuality was observed. These results are similar to those reported of Californian plants, indicating that the Azorean Endarachne have a monophasic heteromorphic life history.

First report of the invasive macroalga Acrothamnion preissii (Rhodophyta, Ceramiales) in the Atlantic Ocean

Abstract Acrothamnion preissii is an invasive species in the Mediterranean Sea, and is listed among the 100 worst non-indigenous species. In July and August 2009, this non-native red macroalga was found for the first time in the Azores (on Santa Maria), and this represents the first record of this species in the Atlantic. Here, we describe the establishment of this invasive species in the Atlantic. In recent surveys, A. preissii displayed an invasive behaviour. As suggested for the Mediterranean Sea, hull fouling is the most likely vector for its introduction into the Azores.

Life history and morphological studies of Punctaria tenuissima (Chordariaceae, Phaeophyceae), a new record for the Azores

Punctaria tenuissima (Chordariaceae, Phaeophyceae) is reported for the first time from the Azores. Erect thalli were collected on the Island of Sao Miguel; they were up to 3 cm long, flattened and often twisted. The plurilocular sporangia were formed from surface cells that were quadrate or rectan- gular in surface view. Unilocular sporangia were not observed in the field. In culture, the plurispores of P. tenuis- sima developed into Hecatonema-like, tufted, prostrate thalli that formed plurilocular sporangia. The plurispores of the prostrate thalli cultured at 158C with a long day (LD) pho- toperiod developed into new prostrate thalli, which in turn formed plurilocular sporangia. This cycle was repeated 5 times, resulting in several generations of reproductive pros- trate thalli. When these cultures were cooled to 108C with a short day (SD) photoperiod, new erect thalli developed from the prostrate thalli resembling the thalli collected in the field. These erect blades produced unilocular and plurilocular spo- rangia on the same or on different thalli. The plurispores and unispores produced by the erect thalli at 108C under SD con- ditions once again developed into new prostrate thalli. This is the first report of unilocular sporangia formed in cultures of P. tenuissima. Sexual reproduction was not observed. The culture conditions, particularly temperature and daylength, appeared to influence the formation of erect blades. The Punctaria-like thalli were produced in 108C/SD conditions, whilst the Hecatonema-like thalli were produced under 108-158C/LD and SD conditions. These results are similar to those reported for P. tenuissima from other locations and suggest the occurrence of both direct and heteromorphic life histories in the Azorean algae.