Multigene analyses resolve early diverging lineages in the Rhodymeniophycidae (Florideophyceae, Rhodophyta).

Multigene phylogenetic analyses were directed at resolving the earliest divergences in the red algal subclass Rhodymeniophycidae. The inclusion of key taxa (new to science and/or previously lacking molecular data), additional sequence data (SSU, LSU, EF2, rbcL, COI-5P), and phylogenetic analyses removing the most variable sites (site stripping) have provided resolution for the first time at these deep nodes. The earliest diverging lineage within the subclass was the enigmatic Catenellopsis oligarthra from New Zealand (Catenellopsidaceae), which is here placed in the Catenellopsidales ord. nov. In our analyses Atractophora hypnoides was not allied with the other included Bonnemaisoniales, but resolved as sister to the Peyssonneliales, and is here assigned to Atractophoraceae fam. nov. in the Atractophorales ord. nov. Inclusion of Acrothesaurum gemellifilum gen. et sp. nov. from Tasmania has greatly improved our understanding of the Acrosymphytales, to which we assign three families, the Acrosymphytaceae, Acrothesauraceae fam. nov. and Schimmelmanniaceae fam. nov. This article is protected by copyright. All rights reserved

The genera Melanothamnus Bornet & Falkenberg and Vertebrata S.F. Gray constitute well-defined clades of the red algal tribe Polysiphonieae (Rhodomelaceae, Ceramiales).

Polysiphonia is the largest genus of red algae, and several schemes subdividing it into smaller taxa have been proposed since its original description. Most of these proposals were not generally accepted, and currently the tribe Polysiphonieae consists of the large genus Polysiphonia (190 species), the segregate genus Neosiphonia (43 species), and 13 smaller genera (< 10 species each). In this paper, phylogenetic relationships of the tribe Polysiphonieae are analysed, with particular emphasis on the genera Carradoriella, Fernandosiphonia, Melanothamnus, Neosiphonia, Polysiphonia sensu stricto, Streblocladia and Vertebrata. We evaluated the consistency of 14 selected morphological characters in the identified clades. Based on molecular phylogenetic (rbcL and 18S genes) and morphological evidence, two speciose genera are recognized: Vertebrata (including the type species of the genera Ctenosiphonia, Enelittosiphonia, Boergeseniella and Brongniartella) and Melanothamnus (including the type species of the genera Fernandosiphonia and Neosiphonia). Both genera are distinguished from other members of the Polysiphonieae by synapomorphic characters, the emergence of which could have provided evolutionarily selective advantages for these two lineages. In Vertebrata trichoblast cells are multinucleate, possibly associated with the development of extraordinarily long, photoprotective, trichoblasts. Melanothamnus has 3-celled carpogonial branches and plastids lying exclusively on radial walls of the pericentral cells, which similarly may improve resistance to damage caused by excessive light. Other relevant characters that are constant in each genus are also shared with other clades. The evolutionary origin of the genera Melanothamnus and Vertebrata is estimated as 75.7-95.78 and 90.7-138.66 Ma, respectively. Despite arising in the Cretaceous, before the closure of the Tethys Seaway, Melanothamnus is a predominantly Indo-Pacific genus and its near-absence from the northeastern Atlantic is enigmatic. The nomenclatural implications of this work are that 46 species are here transferred to Melanothamnus, six species are transferred to Vertebrata and 13 names are resurrected for Vertebrata

Analysis of chloroplast genomes and a supermatrix inform reclassification of the Rhodomelaceae (Rhodophyta).

With over a thousand species, the Rhodomelaceae is the most species-rich family of red algae. While its genera have been assigned to 14 tribes, the high-level classification of the family has never been evaluated with a molecular phylogeny. Here, we reassess its classification by integrating genome-scale phylogenetic analysis with observations of the morphological characters of clades. In order to resolve relationships among the main lineages of the family we constructed a phylogeny with 55 chloroplast genomes (52 newly determined). The majority of branches were resolved with full bootstrap support. We then added 266 rbcL, 125 18S rRNA gene and 143 cox1 sequences to construct a comprehensive phylogeny containing nearly half of all known species in the family (407 species in 89 genera). These analyses suggest the same subdivision into higher-level lineages, but included many branches with moderate or poor support. The circumscription for nine of the 13 previously described tribes was supported, but the Lophothalieae, Polysiphonieae, Pterosiphonieae and Herposiphonieae required revision, and five new tribes and one resurrected tribe were segregated from them. Rhizoid anatomy is highlighted as a key diagnostic character for the morphological delineation of several lineages. This work provides the most extensive phylogenetic analysis of the Rhodomelaceae to date and successfully resolves the relationships among major clades of the family. Our data show that organellar genomes obtained through high-throughput sequencing produce well-resolved phylogenies of difficult groups, and their more general application in algal systematics will likely permit deciphering questions about classification at many taxonomic levels

Analysis of chloroplast genomes and a supermatrix inform reclassification of the Rhodomelaceae (Rhodophyta).

With over a thousand species, the Rhodomelaceae is the most species-rich family of red algae. While its genera have been assigned to 14 tribes, the high-level classification of the family has never been evaluated with a molecular phylogeny. Here, we reassess its classification by integrating genome-scale phylogenetic analysis with observations of the morphological characters of clades. In order to resolve relationships among the main lineages of the family we constructed a phylogeny with 55 chloroplast genomes (52 newly determined). The majority of branches were resolved with full bootstrap support. We then added 266 rbcL, 125 18S rRNA gene and 143 cox1 sequences to construct a comprehensive phylogeny containing nearly half of all known species in the family (407 species in 89 genera). These analyses suggest the same subdivision into higher-level lineages, but included many branches with moderate or poor support. The circumscription for nine of the 13 previously described tribes was supported, but the Lophothalieae, Polysiphonieae, Pterosiphonieae and Herposiphonieae required revision, and five new tribes and one resurrected tribe were segregated from them. Rhizoid anatomy is highlighted as a key diagnostic character for the morphological delineation of several lineages. This work provides the most extensive phylogenetic analysis of the Rhodomelaceae to date and successfully resolves the relationships among major clades of the family. Our data show that organellar genomes obtained through high-throughput sequencing produce well-resolved phylogenies of difficult groups, and their more general application in algal systematics will likely permit deciphering questions about classification at many taxonomic levels

A morphological study and taxonomic revision of <i>Euptilota</i> (Ceramiaceae, Rhodophyta)

A reassessment of the genus Euptilota reveals that it presently contains four validly published species: E. formosissima (Montagne) Kützing from New Zealand and the islands of the Campbell Plateau, E. articulata (J. Agardh) Schmitz from Australia, India, South Africa and Japan, E. fergusonii Cotton from the Indian Ocean, and E. molle (Wollaston) comb. nov., from the eastern part of South Africa. Euptilota pappeana Kützing from the Western Cape Province, South Africa, and E. mooreana Lindauer from New Zealand are excluded from the genus. Euptilota is characterized by: alternate-distichous branching at the apex, a prominent central axis covered by a small-celled outer cortex and with internal rhizoidal filaments, spermatangia with a terminal nucleus subtended by a single mucilage-containing vesicle, and fertile female periaxial cells borne in the plane of lateral branching. The carpogonium does not divide after fertilization and produces two tubular protuberances that are cut off as connecting cells. Traditionally placed in the tribe Ptiloteae, Euptilota appears to be more closely related to the Callithamnieae. As in the Callithamnieae, periaxial cells are cut off longitudinally in pairs from the fertile axial cell. One of each pair bears a horizontally oriented four-celled carpogonial branch and both cut off auxiliary cells after fertilization. Sterile group cells are absent. Connecting cells mediate transfer of the derivatives of the fertilization nucleus to the auxiliary cells. A diploid nucleus divides at the surface of an auxiliary cell and one daughter nucleus moves to its centre while the other is extruded into a residual cell. The haploid auxiliary cell nucleus is cut off into a foot cell. It is proposed that the closest relatives of Euptilota are Seirospora and Sciurothamnion

Characterization of <i>Martensia</i> (Delesseriaceae, Rhodophyta) based on a morphological and molecular study of the type species, <i>M. elegans</i>, and <i>M. natalensis</i> sp. nov. from South Africa

An examination of a series of collections from the coast of Natal, South Africa, has revealed the presence of two species of Martensia C. Hering nom. cons: M. elegans C. Hering 1841, the type species, and an undescribed species, M. natalensis sp. nov. The two are similar in gross morphology, with both having the network arranged in a single band, and with reproductive thalli of M. elegans usually larger and more robust than those of M. natalensis. Molecular studies based on rbcL sequence analyses place the two in separate, strongly supported clades. The first assemblage occurs primarily in the Indo-West Pacific Ocean, and the second is widely distributed in tropical and warm-temperate waters. Criteria that have been used in the past for separating the two, namely, the number and shape of the blades, the presence of a single- versus a multiple-banded network, and blade margins entire or toothed, were determined to be unreliable. Although the examination of additional species is required, the morphology and position of procarps and cystocarps, whether at or near the corners of the longitudinal lamellae and the cross-connecting strands or along the lobed, membranous edges of the longitudinal lamellae or on the thallus margins, may prove to be diagnostic at the subgenus level. We recognize subg. Martensia, including the type of Martensia: M. elegans and subg. Mesotrema (J. Agardh) De Toni based on Martensia pavonia (J. Agardh) J. Agardh

Journal of Phycology 39 1 154 171 Blackwell Science Ltd

A phylogeny has been inferred from parsimony and likelihood analyses of plastid rbcL DNA sequences for seven recognized and six undescribed species of Gracilariopsis (Gp.) (Gracilariales, Rhodophyta). New descriptions and illustrations of cystocarp morphology are provided for four Gracilariopsis species from North and South America. The generitype, Gp. sjoestedtii (Kylin) Dawson, is reinstated to include plants distributed from British Columbia to Pacific Baja California, and the name is corrected to Gp. andersonii (Grunow) Dawson. Gracilariopsis lemaneiformis (Bory) Dawson, Acleto et Foldvik is shown not to have a worldwide distribution but to be restricted to the vicinity of Peru. Gracilariopsis costaricensis is recognized with the provision that it may prove to be conspecific with Gp. lemaneiformis. Gracilariopsis &#39;lemaneiformis&#39; from North and South Carolina is described as a new species, Gp. carolinensis Liao et Hommersand sp. nov. Gracilariopsis longissima (Gmelin) Steentoft, Irvine et Farnham from Western Europe and the Mediterranean Sea and Gp. tenuifrons (Bird et Oliveira) Fredericq et Hommersand from the Caribbean Sea and Brazil are recognized. Entities that have been referred to Gp. &#39;lemaneiformis&#39; from China and Japan constitute an undescribed species that is related to Gp. heteroclada Zhang et Xia. An invasive species from the Gulf of California, Mexico, and South Australia that has been assigned to Gp. &#39;lemaneiformis&#39; is resolved in a clade that includes Gp. longissima. Four undescribed species are included in the molecular analyses. The systematics of Gracilariopsis is discussed in the light of the morphological and molecular evidence