Abstract:The coral reefs of Pirangi beach have suffered the impact of anthropic actions, mainly those related to tourism. To evaluate these effects, algal samples were collected at nine stations, distributed along the reef fringe. The macrobenthic community (algae/coral) was identified through photographic methods. A total of thirty species of algae, five species of coral, and one species of mollusk were identified. In areas of intense tourist activity, small algae were predominant, while in areas without human interference, foliose algae were predominant. Cluster analysis of the organisms revealed a pattern in spatial distribution into five zones: (1) a submerged zone with very diverse flora, (2) a zone with a predominance of Caulerpa racemosa, (3) a zone with high coverage of Sargassum vulgare, (4) a trampled zone with bare spaces, small algae and Zoanthus sociatus, and (5) a zone with predominance of Palythoa caribaeroum. The results show that human disturbances of the natural order can result in a different distribution model for benthic organisms in reefs. Moreover, these results allow us to infer that the area studied has undergone changes resulting from human activities and that the differences in biological composition can be used as an important indicator of the health of the Pirangi reef.

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Algae of Halymeniales (Rhodophyta) present a wide ecological and economic importance, as primary producers and bioactive compounds producers, and include invasive species worldwide. Its taxonomy is quite problematic, with reports of misidentifications and nomenclatural changes. Therefore, studies have included molecular tools to assist the morphological taxonomy of this order. This study aims to investigate through molecular and morphological techniques the diversity of Halymeniales along the Brazilian coast, in order to contribute to the knowledge of native marine flora. Three molecular markers were sequenced, UPA, COI-5P and rbcL, whose data were allied to morphological characters and resulted in 26 delimited species. There are 11 new species to science: Corynomorpha cf. clavata, two taxa morphologically identified as "Cryptonemia" crenulata, two taxa morphologically identified as Cryptonemia seminervis, Halymenia ignifera, Halymenia pinnatifida, Halymenia silviae, Grateloupia cf. dichotoma, Grateloupia cf. filicina 1 and Grateloupia cf. filicina 2. At least seven new genera were found, represented by the following taxa: "Cryptonemia" bengryi, representatives of "Cryptonemia" crenulata complex, "Cryptonemia" delicatula, "Halymenia" elongata, "Halymenia" floridana, Halymeniales sp. 1 and Halymeniales sp. 2. Three species whose type locality is Asia were detected: Grateloupia orientalis, Grateloupia turuturu and Grateloupia yangjiangensis. Among taxa previously recorded to Brazilian coast, nine were not found. If those taxa constitute valid species, the diversity of the order in Brazil will be represented by 35 species. Phylogenetic analyses showed that Cryptonemia, Halymenia and Grateloupia constitute non-monophyletic groups. Results demonstrated the existence of wide cryptic and pseudo-cryptic diversity as well as novel species and genera, and revealed the presence of non-native species.

Phylogenetic relationships and species diversity within the genus Halymenia along the Brazilian coast were investigated through molecular and morphological analyses. Molecular studies included UPA, COI-5P and rbcL markers. A total of five Halymenia species were found: Halymenia cearensis sp. nov., H. ignifera, H. pinnatifida, H. silviae and H. cf. mirabilis. Halymenia cearensis was molecularly distinct from all other Halymenia species included in this study and is morphologically characterized by: cleft, lobate, oblong or obovate blades with broad base; apex irregular in shape; surface with bullations, rugosities, spiny and globular papillae irregularly distributed; abundant and conspicuous ganglionic cells throughout; blades up to 800 µm thick at base; outer cortical cells ellipsoidal or ovoid in shape, higher than broad; and inner cortex cells 4–25 µm in width. Our phylogeny demonstrated that entities attributed to H. floridana and H. elongata occurring in Brazil correspond to two distinct genera, which was also supported by morphological and ecological data. The use of molecular tools was crucial to provide a better understanding of the diversity of Brazilian marine flora.