We evaluated the relationships among species in the genus Gelidiella using 47 rbcL and 29 COI sequences, including those from 18 specimens collected in Madagascar. Molecular analyisis revealed the presence of three major lineages among Magalasy Gelidiella which were assigned, based on morpho-anatomical observation, to Gelidiella acerosa, G. ligulata and a so far not described species for which we here proposed the name G. incrassata. Both molecular and morphological data demonstrated the presence of three species in Madagascar: the G. acerosa complex, G. ligulata, and G. incrassata sp. nov., described here. Gelidiella incrassata was collected on small gravel from the intertidal down to a depth of 14 m on the southeast coast of Madagascar. It is distinguished by its large size (up to 7 cm), opposite to alternate ramuli, thick-walled cortical and medullary cells, and stalked tetrasporangial stichidia with irregular arrangement of tetrasporangia. Phylogenetic analyses of rbcL and COI sequences revealed the sister relationship between G. incrassata and G. fanii from southeast Asia and Hawaii. Gelidiella acerosa comprised three genetic groups in Madagascar, each being genetically distinct (pairwise distances, 4.9–8.3% for COI and 1.2–2.3% for rbcL). Further sampling of G. acerosa is needed before taxonomic revisions can be proposed. The distribution of G. ligulata is expanded to include the southwest Indian Ocean.

ATIMO VATAE

We analyzed both mitochondrial cox1 and plastid rbcL sequences from specimens of Pterocladiella from Madagascar and compared their morphologies with previously described species in the genus. Both molecular and morphological datasets demonstrated the presence of five species in Madagascar: P. australafricanensis, P. bartlettii, P. caerulescens, and two new species, P. feldmannii and P. hamelii, described here. Pterocladiella feldmannii is distinguished by plants with a size of about 6 cm with narrow axes and opposite to irregular branches, rhizines congested in medulla, tetrasporangial branchlets constricted at base of branches, tetrasporangial sori without sterile margins, and irregular arrangement of tetrasporangia. Pterocladiella hamelii is characterized by plants with a size of about 3 cm with flattened and thin erect axes and irregular branches, radial arrangement of subapical cells at tips of main axes, tetrasporangial sori with sterile margins and horizontal to irregular arrangement of tetrasporangia. Phylogenetic analyses based on cox1 and rbcL sequences revealed the sister relationship between P. feldmannii and P. hamelii, and their distant relationships to P. australafricanensis, P. bartlettii, and P. caerulescens. The Madagascan Pterocladiella is composed of two geographical elements: Madagascan endemic (P. feldmannii and P. hamelii) and species with wide distributions (P. australafricanensis, P. bartlettii and P. caerulescens).

ATIMO VATAE

ATIMO VATAE

We investigated the globally distributed red algal genus Pterocladiella , comprising 24 described species, many of which are economically important sources of agar and agarose. We used DNA-based species delimitation approaches, phylogenetic, and historical biogeographical analyses to uncover cryptic diversity and infer the drivers of biogeographic patterns. We delimited 43 species in Pterocladiella , of which 19 are undescribed. Our multigene time-calibrated phylogeny and ancestral area reconstruction indicated that Pterocladiella most likely originated during the Early Cretaceous in the Tethys Sea. Ancient Tethyan vicariance and long-distance dispersal have shaped current distribution patterns. The ancestor of Eastern Pacific species likely arose before the formation of the formidable Eastern Pacific Barrier—a first confirmation using molecular data in red algae. Divergences of Northeast and Southeast Pacific species have been driven by the Central American Seaway barrier, which, paradoxically, served as a dispersal pathway for Atlantic species. Both long- and short-distance dispersal scenarios are supported by genetic relationships within cosmopolitan species based on haplotype analysis. Asymmetrical distributions and the predominance of peripatry and sympatry between sister species suggest the importance of budding speciation in Pterocladiella . Our study highlights the underestimation of global diversity in these crucial components of coastal ecosystems and provides evidence for the complex evolution of current species distributions.

ATIMO VATAE, KARUBENTHOS 2012, MADIBENTHOS, PAPUA NIUGINI

The diversity of red algae is significantly increasing; in the recent interest of climate changes, taxonomic and biogeographic studies are needed in untouched regions such as ecological important islands. We examined a collection of Gelidium specimens gathered during the 2010 Atimo Vatae expedition based on the morphology and DNA sequencing of mitochondrial cox1 and plastid rbcL. Both morphological and molecular datasets demonstrated the presence of three species in Madagascar; G. leptum G.H.Boo, L.Le Gall and H.S.Yoon, sp. nov., described here, and G. sclerophyllum W.R.Taylor and G. usmanghanii Afaq-Husain and Shameel. Gelidium leptum is distinguished by thin, slender, flattened thalli with irregular branches, compactly arranged thickwalled cells in medulla, sparse rhizoidal filaments at both sides of branches, and elongate sori of tetrasporangia. Gelidium sclerophyllum, previously considered as endemic to the Tropical Eastern Pacific, is first reported in the Indian Ocean and Hawai’i; G. usmanghanii, previously reported to occur in Pakistan and Oman, also presents a first record in the Southern Hemisphere. Phylogenies inferred from cox1 and rbcL sequences suggests that each of the three species likely diverged from different ancestors. The Madagascan Gelidium comprises two geographical elements; Madagascan endemic (G. leptum) and widespread species (G. sclerophyllum and G. usmanghanii).

ATIMO VATAE

ATIMO VATAE

The present study documents species of coralline algae that form maerl and rhodoliths in Guadeloupe, Caribbean using an integrative systematic approach of combining molecular (COI-5P, psbA) and morphological/anatomical data. Maerl and rhodoliths were collected by SCUBA and dredging from six localities in Guadeloupe during the Karubenthos Expedition, which was coordinated by the Parc National de la Guadeloupe and the Muséum National d´Histoire Naturelle. Of the twelve maerl and rhodolith specimens collected and sequenced, eight specific entities were delimitated based on the analysis of molecular data: Lithothamnion cf. ruptile, five species of the genus Lithothamnion, one species of the genus Spongites, and the remaining one was either assigned to the genus Lithoporella or Mastophora. Morphological/anatomical data are presented for each of these species. Molecular analyses revealed that Lithothamnion. cf ruptile and other four species (Lithothamnion spp.1–4) were resolved in a distinct lineage than the other Lithothamnion species examined. Nevertheless, these five species were provisionally remained in the genus Lithothamnion based on the presence of flared epithallial cells. Previously, only three species of Lithothamnion have been cited in the Caribbean. Till this study species belonging to the genus Spongites have not been hitherto reported for this region. The specimen identified as either Lithoporella or Mastophora shared anatomical features with both genera. Further examination of reproductive material is required to identify this specimen to a lower taxonomical rank. This study is the first to report the occurrence of maerl and rhodoliths belonging to the genus Lithothamnion at 110 m depth; this record being the deepest for the genus in the Caribbean Sea. Our results have revealed that species diversity of Caribbean maerl has been underestimated and further surveys coupled with an integrative taxonomic approach on this biodiversity hotspot are necessary.

KARUBENTHOS 2012

Non‐geniculate coralline algae are difficult to identify based solely on morpho‐anatomy. To address the systematics of several taxonomically challenging taxa, we analyzed DNA sequences of a short portion (118‐296 base pairs) of the 3’ end of the rbcL gene from three type specimens. The analyses revealed that Harveylithon munitum (basionym: Lithophyllum munitum), described in 1906 from Cave Cays, Exuma Chain, Bahamas, is conspecific with both Goniolithon accretum and Goniolithon affine, described in 1906 from Sand Key, Florida and in 1907 from Culebra Island, Puerto Rico, respectively. L. munitum and G. accretum were described in the same 1906 publication and have equal priority. We have selected the currently accepted and most commonly used name H. munitum to apply to this entity. Comparative analyses of rbcL, psbA, UPA, COI, and LSU sequences from contemporary field‐collected specimens revealed that H. munitum currently inhabits mesophotic rhodolith beds in the northwestern Gulf of Mexico, as well as the intertidal zone in the Florida Keys, Honduras, Atlantic Mexico, Caribbean Panama, and Guadeloupe, French West Indies. Species delimitation analyses reveal that the Western Atlantic and Australian H. munitum populations may be separate species. Two new species of Harveylithon from the northwestern Gulf of Mexico and one new species from the southwestern Gulf of Mexico, the Caribbean, and the Red Sea were also identified in the analyses and are described.

KARUBENTHOS 2012

The systematics of the Laurencia complex was investigated using a taxon-rich data set including the chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene only and a character-rich data set combining mitochondrial cytochrome oxidase 1 (COI-5P), the rbcL marker, and the nuclear large subunit of the ribosomal operon (LSU). Bayesian and ML analyses of these data sets showed that three species hitherto placed in the genus Laurencia J.V.Lamour. were not closely related to Laurencia s. str. Laurencia caspica Zinova & Zaberzhinskaya was the sister group of the remaining Osmundea Stackh. species, L. crustiformans McDermid joined Palisada and L. fl exilis Setch. consisted of an independent lineage. In light of these results a new genus, Ohelopapa F.Rousseau, Martin-Lescanne, Payri & L.Le Gall gen. nov., is proposed to accommodate L. fl exilis. This new genus is morphologically characterized by four pericentral cells in each vegetative axial segment; however, it lacks ‘corps en cerise’ in cortical cells and secondary pit connections between cortical cells, which are characteristic of Laurencia. Three novel combinations are proposed to render the classifi cation closer to a natural system: Ohelopapa fl exilis (Setch.) F.Rousseau, Martin-Lescanne, Payri & L.Le Gall comb. nov., Osmundea caspica (Zinova & Zaberzhinskaya) Maggs & L.M.McIvor comb. nov. and Palisada crustiformans (McDermid) A.R.Sherwood, A.Kurihara & K.W.Nam comb. nov.

KARUBENTHOS 2012