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Phymatolithon atlanticum is newly described from France and Northern Ireland (the United Kingdom) using both molecular (rbcL sequence data, concatenated psbA and COI-5P datasets) and morpho-anatomical analyses. The species shows sequence divergences from other Phymatolithon species by 10.7–15.3% in rbcL, 5.1–9.2% in psbA and 9.6–16.8% in COI-5P. Morpho-anatomically, P. atlanticum is encrusting to lumpy, has slightly sunken female conceptacles with raised rims, lacks buried conceptacles, has five to six rosette cells surrounding tetra/bisporangial conceptacle pores, and has tetra/bisporangial conceptacle roofs that are pitted with depressions as a result of the disintegration of rosette cells. This latter feature is what currently separates the species morpho-anatomically from all other species of Phymatolithon. The tetra/bisporangial conceptacle of P. atlanticum closely resembles those of Lithothamnion crispatum and Leptophytum bornetii and may well represent additional examples of convergent evolution in the non-geniculate coralline algae.

Molecular phylogenetic analyses discovered an unexpected biodiversity of coralline algae in modern oceans. This species richness is unlikely to be an exclusive characteristic of recent ecosystems. With the aim to investigate fossil coralline biodiversity, a large dataset of western Mediterranean Miocene specimens, previously identified as Spongites fruticulosus (and synonymized taxa), have been re-vised based on the current taxonomic framework. The analysis recognized two distinct groups. The first group includes the specimens fitting within the current description of S. fruticulosus. The second group consists of Chamberlainium pentagonum comb. nov., the first fossil representative of the genus. This species has been separated from S. fruticulosus on the basis of its smaller conceptacles and its thinner conceptacle roof. The very same characters have been highlighted by modern molecular phylogenetic analyses for separating Chamberlainium from Spongites. Chamberlainium pentagonum, simi-larly to the fossil specimens of Spongites fruticulosus, occurs in most of the investigated area and the two species coexist in several localities, indicating a similar and broad ecological tolerance for both taxa. These results suggest that Miocene coralline algal biodiversity is probably underestimated and prove the convenience of using large datasets for the study of fossil coralline algae.

Adeylithon gen. nov. with one species, A. bosencei sp. nov., belonging to the subfamily Hydrolithoideae is described from Pacific coral reefs based on psbA sequences and morpho-anatomy. In contrast with Hydrolithon, A. bosencei showed layers of large polygonal "cells," which resulted from extensive lateral fusions of perithallial cells, interspersed among layers of vegetative cells. This anatomical feature is shared with the fossil Aethesolithon, but lacking DNA sequences from the fossils and the fragmentary nature of Aethesolithon type material, we cannot ascertain if Adeylithon and Aethesolithon are congeneric. Morpho-anatomical features of A. bosencei were generally congruent with diagnostic features of the subfamily Hydrolithoideae: (i) outline of cell filaments entirely lost in large portions due to pervasive and extensive cell fusions, (ii) trichocytes not arranged in tightly packed horizontal fields, (iii) basal layer without palisade cells, and (iv) cells lining the canal pore oriented more or less perpendicular to roof surface and not protruding into the canal. However, it showed a predominant monomerous thallus organization and trichocytes were disposed in large pustulate, horizontal fields, although they were not tightly packed and did not become distinctly buried in the thallus. Only mature tetrasporangial conceptacles were observed, therefore the type of conceptacle roof formation remained undetermined. Adeylithon bosencei occurs on shallow coral reefs, in Australia, Papua New Guinea, and South Pacific islands (Fiji, Vanuatu). Fossil Aethesolithon is considered an important component of shallow coral reefs since the Miocene; fossil records showed a broad Indo-Pacific distribution, but a long-term process of range contraction in the last 2.6 million years, resulting in an overlap with the distribution of the extant Adeylithon. While the congeneric nature of extant and fossil taxa remained uncertain, similarities in morpho-anatomy, habitat, and distribution may indicate that both taxa likely shared a common ancestor.

The diagnosis of the order Sporolithales is currently restricted to tetrasporangial anatomy. Until recently, there were few reports about gametangial, and more specifically carposporangial material for the Sporolithales. This study provides the first detailed observations of the anatomy of the mature carposporophyte phase from three species of Sporolithales commonly found in rhodolith beds from Brazil: Sporolithon episporum, S. ptychoides, and Sporolithon sp. Using these observations, along with previously published descriptions and illustrations from other representative species in the order, a comparison was made with the other three orders (Corallinales, Hapalidiales, and Rhodogorgonales) of the Corallinophycidae. We amend the diagnosis of the order Sporolithales to include the anatomy of the mature carposporophyte as follows: carposporangial conceptacles that lack a central fusion cell, but instead with numerous, short, one to two-celled, filaments that bear oblong terminal carposporangia that are distributed across the conceptacle chamber floor and walls.

(Spongites yendoi (Foslie) Chamberlain (Corallinales, Rhodophyta) on the coast of Bahia, Brazil). We report the first occurrence of S. yendoi (Foslie) Chamberlain on the northeastern coast of Brazil, and the second record of the species on the Brazilian coast. We collected specimens on two beaches in the cities of Salvador and Camacari, Bahia, Brazil. The species were identified by the presence of monomerous thallus construction, trichocytes arranged in horizontal fields, central columella, and tetrasporangial conceptacle morphometry. Our record extends the distribution range of this species into Brazilian waters.

Sporolithon ptychoides Heydrich (Sporolithaceae, Sporolithales), the type species of the genus Sporolithon, is newly reported for Thai waters based on specimens collected from the Gulf of Thailand and the Andaman Sea. A detailed morphological and anatomical account is provided, including comparisons with published data of S. ptychoides and its related species. Epithallial cells are flared. Cells of adjacent filaments connect laterally mostly by secondary pit connections. Tetrasporangia are grouped in sori that occur in patches over the thallus surface. Sori are buried in distinct rows in the thallus. Details of male, female and carposporangial conceptacles of S. ptychoides are described for the first time. Gametangial thalli are monoecious with spermatangia and carposporangia born in uniporate conceptacles. Dendroid spermatangial branches occur on the floor, walls and roof of the male conceptacle chamber. Carpogonial branch consists of a hypogenous cell and a carpogonium. Central fusion cell is a...

Maneveldt G.W. and van der Merwe E. 2012. Heydrichia cerasina sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta) from the southernmost tip of Africa. Phycologia 51: 11–21. DOI: 10.2216/11-05.1 A new species of Heydrichia (Sporolithales), Heydrichia cerasina sp. nov., is described, found only on pebbles in the low intertidal zone along a 10 km stretch of the South African south coast from Cape Agulhas to Struisbaai. The species is characterized by the following suite of features that distinguish it from the other two species of Heydrichia found in South Africa: (1) unusual cherry-red colour when freshly collected; (2) uniformly warty growth form; (3) relatively thin crust (up to 1400 µm thick); (4) tetra/bisporangial sori comprised of mostly single sporangial chambers; and (5) unbranched spermatangial structures distributed on the floor, walls, and roof of the mature male conceptacle. The species appears to be most closely related to Heydrichia homalopasta from Australia. This study has affirmed that ...

Villas-Boas A.B., Riosmena-Rodriguez R., Amado-Filho G.M., Maneveldt G.W. and de O. Figueiredo M.A. 2009. Rhodolith-forming species of Lithophyllum (Corallinales; Rhodophyta) from Espirito Santo State, Brazil, including the description of L. depressum sp. nov. Phycologia 48: 237–248. DOI: 10.2216/08-35.1. The taxonomy of the rhodolith-forming species of Lithophyllum (Corallinales, Rhodophyta) found from Espirito Santo State, Brazil, were evaluated based on extensive subtidal sampling. A comparative analysis of the Brazilian material with recently described species lead us to conclude that three known species (Lithophyllum corallinae, L. johansenii, L. stictaeforme) and one species new to science (Lithophyllum depressum Villas-Boas, Figueiredo & Riosmena-Rodriguez) are present in the area. All four species can be distinguished primarily by their tetrasporangial conceptacle roof anatomy. This study has shown that Brazilian rhodolith beds are comparatively more diverse in number of Lithophyllum spec...

Studies of the genus Amphiroa (Corallinales, Rhodophyta) along the southern Baja California Peninsula, Mexico, were undertaken to determine how many species were present and to assess the characters that have been or could be used in species delimitation. After analysis of 800 specimens from 60 localities, we conclude that five species are present: A. valonioides Yendo, A. misakiensis Yendo, A. vanbosseae Lemoine, A. rigida Lamouroux and A. beauvoisii Lamouroux. Amphiroa brevianceps Dawson and A. magdalensis Dawson are considered heterotypic synonyms of A. misakiensis. Characters used here for the first time to delimit species of Amphiroa include shape of gametangial conceptacle chambers, ontogeny of the pore of the gametangial conceptacle, the type of spermatangia present, the position of gonimoblast filaments and the form of the cortical cells. Characters used in species delimitation in Amphiroa are discussed in detail and a key to the species found in southern Baja California is provided.

The genus Synarthrophyton (Corallinaceae, Rhodophyta) is represented in southern Australia by one species, S. patena (Hooker et Harvey in Harvey) Townsend. New data have shown that cell fusions vary in size and occur in both anticlinal and periclinal cell walls, and as a result can no longer be used to delimit Synarthrophyton from other genera of Melobesioideae. Male conceptacle development is described for the first time. Spermatangia are overlain by protective cells during early stages of development. Mature spermatangial branches may be either dendroid or both dendroid and simple. Growth-form is more varied than hitherto thought and includes specimens previously identified as Lithothamnion muelleri Lenormand ex Rosanoff. An updated description of Synarthrophyton is presented and the relationships of Synarthrophyton to other genera of the subfamily Melobesioideae are considered. New information is provided on host range, seasonal and geographic distribution in southern Australia.

Hydrolithon pellire sp. nov. (Rhodophyta, Corallinaceae) is a thin, crustose epiphyte that grows mainly on intertidal plants of Gelidium pteridifolium R.E. Norris, Hommersand et Fredericq in Natal and eastern Cape Province, South Africa. It has cell fusions and uniporate tetrasporangial conceptacles characteristic of the subfamily Mastophoroideae. The conceptacle pore is surrounded by enlarged, vertically oriented cells characteristic of the genus Hydrolithon. Hydrolithon pellire appears to have a germination disc of c. 48, small, squarish cells; this type of disc is normally associated with the multiporate genus Melobesia.

Studies of the type of Fosliella (Corallinaceae, Rhodophyta), F. farinosa (Lamouroux) Howe, have shown that it possesses features considered characteristic of Hydrolithon. Tetrasporangial conceptacle pore canals are lined by conspicuous elongate cells arising from filaments interspersed amongst sporangial initials; these cells do not protrude laterally into the canal and are oriented more or less perpendicularly to the roof surface. This new information has led to the conclusion that Fosliella and Hydrolithon are congeneric. Thus, Fosliella Howe 1920 becomes a heterotypic synonym of Hydrolithon Foslie 1909 and Fosliella farinosa (Lamouroux) Howe is transferred to Hydrolithon as H. farinosum (Lamouroux) comb. nov. It has also been shown that the spore germination disc consists of a 4-celled central element surrounded by 12 cells, and it is proposed that thin plants traditionally attributed to Fosliella be referred to as the Fosliella-state of Hydrolithon. Recent changes to generic delimitation wit...

A critical study of the crustose marine red alga Sporolithon episoredion (Adey, Townsend et Boykins) comb. nov. (Sporolithoideae, Corallinales) from the Spermonde Archipelago, southwestern Sulawesi, Indonesia, has been carried out. Gametangia and carposporangia are described in detail for the first time. Spermatangia are of the dendroid type, and occur on the floor and roof of the conceptacle. Short gonimoblast filaments arise from the dorsal side of the fusion cell. These new data have been used for a more complete characterization of Sporolithon episoredion.

Studies of the type collection and southern Australian populations of Pneophyllum fragile Kutzing, the type species of Pneophyllum(Corallinaceae, Rhodophyta), have shown that considerable variation occurs both in the vegetative thallus and in conceptacle anatomy. Vegetative plants vary from 2–50+ cells in thickness, and thallus margins may be two or more cells in thickness. Tetrasporangial conceptacle roof anatomy also varies in terms of roof thickness, pore canal length, and the occurrence of a columella, but all pore canals are lined by cells that are oriented more or less parallel to the thallus surface, and protruding into the canal, and roofs are formed by filaments surrounding the sporangial initials and interspersed amongst them. These new morphological and anatomical data have shown that Pneophyllum and Spongites can be regarded as distinct genera on the basis of the mode of the tetrasporangial conceptacle formation, but not on differences in thallus thickness, as formerly. In addition, P...

The genus Melobesia (Corallinaceae, Rhodophyta) is represented in southern Australia by two species: M. membranacea (Esper) Lamouroux, which occurs throughout the world, and M. rosanoffii (Foslie) Lemoine, known only from the study region. Detailed studies of the type specimens of both species are provided, together with taxonomic, morphological and anatomical accounts of southern Australian populations. An assessment of diagnostic and ancillary characters has shown that the mode of tetrasporangial and carposporangial conceptacle development, thickness and anatomy of male conceptacle roofs, and thickness and anatomy of carposporangial conceptacle roofs can be used to delimit the species. None of the diagnostic characters used to separate the two southern Australian species has been used previously for species delimitation within the genus. Twelve additional entities reported from southern Australia under the name Melobesia have been excluded from the genus, and one additional species (M. darwinii...

Spongites fruticulosus Kutzing, the type species of Spongites (Corallinaceae, Rhodophyta), which was previously known for certain only from the type specimen, occurs commonly along the southern Aus...

A redescription is given of Lithophyllum orbiculatum (Foslie) Foslie and of its taxonomy, structure, conceptacle initiation and ecology in the British Isles. Due to a misidentification by Foslie, perpetuated by Rosenvinge, Suneson and Adey among others, this name has been erroneously applied to plants from the British Isles, Denmark, Iceland and North America that should be known as L. crouanii Foslie. The application of L. orbiculatum in France has, however, been consistent with the type. The origins of the nomenclatural and taxonomic confusion are documented and the relationships of L. orbiculatum to L. crouanii, and also to L. incrustans Philippi, with which it is often closely associated, are discussed. Generic delimitation within the Lithophylloideae is reconsidered in the light of recent publications; Titanoderma is retained as a separate genus.

The morphology of Goniolithon (Hydrolithon) improceriam Foslie et Howe in Foslie is described from the type and more recent collections of Caribbean material. The species shows a conceptacle development in which the conceptacle is formed before the initiation of sporangia. Certain basal cells within the conceptacle produce spotangial initials as well as cavity cells. The sporangial initials in turn produce more than one tetrasporocyte. Trichocyte/megacyte differentiation as described which has necessitated a redefinition of terminology used for trichocyte differentiation in the Corallinaceae. Attempted placement of Goniolithon improcerum in a number of genera with similar vegetative and reproductive characters, shows, that further investigations of these genera are necessary, before this species can be placed accurately.

The taxonomy of the rhodolith-forming species of non-geniculate coralline algae from the subfamilies Neogoniolithoideae and Hydrolithoideae (Rhodophyta, Corallinales) found from Espírito Santo State, Brazil, was evaluated based on extensive subtidal sampling. A comparative analysis of the Brazilian material to other recently described species lead us to conclude that one relatively well-known species, namely Hydrolithon rupestre, a conferatum species Neogoniolithon cf. brassica-florida and a probably new species of the genus Hydrolithon, are present in the area. All three species can be distinguished by their tetrasporangial or gametangial conceptacle anatomy. This study strengthens the hypothesis that Brazilian rhodolith beds are comparatively more diverse in numbers of rhodolith-forming species than other areas of the world.

Sporolithon (Sporolithaceae, Corallinales) is represented in southern Australia by S. durum (Foslie) Townsend et Woelkerling, comb. nov. The species and the development of male and female-carposporangial conceptacles and tetrasporangial compartments and sori are described in detail for the first time. Information on etymology, collections examined, distribution, seasonality and habit and comparisons with other species is also included. Published records of S. erythraeum from southern Australia have not been substantiated. Two further species have been reported under the generic name Archaeolithothamnion. Archaeolithothamnion australasicum is a species of uncertain status, while A. mirabile is conspecific with Lithothamnion muelleri Lenorrnand ex Rosanoff. Differences between the Sporolithaceae and the Corallinaceae, and the delimitation of genera within the Sporolithaceae, are reconsidered in relation to new data on S. durum. The Sporolithaceae is characterised by tetrasporangia that produce cruciately arranged spores and develop within calcified sporangial compartments, while the Corallinaceae is characterised by tetrasporangia that produce zonately arranged spores that do not develop in calcified sporangial compartments. Two genera of Sporolithaceae are recognised: Heydrichia, in which tetrasporangial compartments are enclosed by modified filaments to form sporangial complexes; and Sporolithon, in which tetrasporangial compartments are not enclosed by modified filaments and sporangial complexes are absent. The concepts of conceptacle and sorus also are reconsidered.

On the basis of a critical study of the holotype specimen, Lithophyllum absimile Foslie & Howe is transferred to the genus Spongites Kutzing, and plants previously reported from the Canary Islands as Lithophyllum absimile or Neogoniolithon absimile (Foslie & Howe) Cabioch are described as a new species: Spongites wildpretii Afonso-Carrillo. The new species is described anatomically and compared with the holotype specimen of Lithophyllum absimile and plants from Japan assigned to L. absimile. Spongites wildpretii is distinguished from the holotype of L. absimile by the lack of excrescences, by the less-developed perithallium and by the small size of cells. It is distinguished from the Japanese plants mainly by reproductive attributes (conceptacle dimensions, conceptacle roof structure and occurrence of columella). A detailed reproductive account of S. wildpretii is provided with special reference to carposporophyte ontogeny. The diagnostic value of the post-fertilization characters as accessory attributes ...

Detailed studies of Synarthrophyton schielianum sp. nov. from the Chatham Islands east of New Zealand have shown that it differs from S. patena, the only other known species in the genus, in a number of respects including the occurrence of ventral struts and volcano-like tetrasporangial conceptacles with a peripheral rim and a central pore-plate within a crater-like depression. Plants commonly overgrow one another, and individual lamellae are spatially separated by struts which have an anatomy like that of the lamellae. Spermatangia occur both on the floor and the roof of conceptacle chambers; both dendroid and simple spermatangial clusters are present. Karyogamy apparently may occur more than once within a single conceptacle, and more than one apparent carposporophyte may subsequently develop. The potential diagnostic value of various characters in species delimitation within Synarthrophyton is discussed. Plants of S. schielianum were most abundantat depths greater than 10 m, showed no evidence ...

Results from critical studies of the original collections upon which Spongites Kutzing, 1841 is based have led to the designation of S. fruticulosa as lectotype species and to the resurrection and recognition of Spongites as a distinct genus of Corallinaceae (Rhodophyta). Spongites is characterized by the absence of geniculae, uniporate tetrasporangial conceptacles, a multistratose non-palisade and non-coaxial medulla (“hypothallium”) and cortex (“perithallium”), fusions between cells of adjacent filaments, and trichocytes which are solitary or arranged in a vertical series. Since at least 1883, the Kutzing epithet “fruticulosa” has been misapplied widely to a taxon with multiporate tetrasporangial conceptacles, whereas the type collection of S. fruticulosa possesses uniporate tetrasporangial conceptacles. Of the six original species, three (S. fruticulosa, S. racemosa, S. stalactitica) are retained in Spongites; S. dentata is referred to Lithophyllum and S. nodosa to Lithothamnion as distinct species; an...

Three species of crustose coralline algae growing almost exclusively on articulated corallines on the west coast of North America have been grouped together in the genus Polyporolithon (Mason, 1953). However, studies of their anatomy and reproduction reveal that they belong to different genera, and they are herein treated as Clathromorphum parcum, Mesophyllum conchatum, and Neopolyporolithon reclinatum, Neopolyporolithon being newly described in this paper. The morphology of these three taxa is described with emphasis on epithallia, host-epiphyte development, and conceptacle formation. Notable are the way in which early development of C. parcum is related to the growth of its host and the manner in which spermatangial conceptacles originate in C. parcum and N. reclinatum. A new tribe in the Melobesioideae, Phymatolitheae, is described. The presence or absence of genicula, of tetrasporangial plugs, and of secondary pit-connections are important characteristics distinguishing the seven subfamilies ...