Adele S. Harvey

CHOREONEMA (CORALLINALES, RHODOPHYTA): 18S rDNA PHYLOGENY AND RESURRECTION OF THE HAPALIDIACEAE FOR THE SUBFAMILIES CHOREONEMATOIDEAE, AUSTROLITHOIDEAE, AND MELOBESIOIDEAE

Phylogenetic analyses of 18S rDNA gene data for Choreonema thuretii (Corallinales, Rhodophyta) and available data for other coralline red algae indicated that Choreonema belongs to the same lineage as other taxa of Corallinales possessing tetra/bisporangial conceptacles with multiporate plates. These results, when integrated with extant morphological/anatomical data, ultrastructural data, and taxonomic data led to the conclusion that all taxa of Corallinales possessing multiporate conceptacles belong to a distinct family, the Hapalidiaceae. Recognition of the Hapalidiaceae as a distinct family was supported both phylogenetically and phenetically. The Hapalidiaceae includes those taxa of Corallinales whose tetrasporangia produce zonately arranged spores and whose tetra/bisporangia are borne in conceptacles, produce apical plugs, and develop beneath multiporate plates. The Hapalidiaceae includes the subfamilies Choreonematoideae, Melobesioideae, and Austrolithoideae, formerly placed in the Corallinaceae sensu lato. The Choreonematoideae lack cell connections between adjacent vegetative filaments and have a multiporate plate that is acellular at maturity, consisting only of a calcium carbonate matrix. The Austrolithoideae and Melobesioideae both have cellular pore plates; taxa of Melobesioideae have cell fusions between cells of adjacent vegetative filaments, whereas taxa of Austrolithoideae lack cellular connections between adjacent vegetative filaments. Inclusion of the Austrolithoideae in the Hapalidiaceae was based entirely on morphological/anatomical evidence; molecular evidence currently is lacking. Relevant historical and nomenclatural data are included.

Utility of psbA and nSSU for phylogenetic reconstruction in the Corallinales based on New Zealand taxa

A number of molecular studies of the Corallinales, a calcified order of the red algae, have used the conservative nSSU gene to investigate relationships within the order. However interspecific variation at this locus is low for closely related species, limiting resolution of recently diverged groups. In this study, we obtained psbA sequence data from specimens of the order from New Zealand that had been identified according to current taxonomic criteria. We compared phylogenetic analyses based on psbA with those based on nSSU for the same dataset, and also analysed nSSU sequences of the New Zealand material with nSSU sequences of Corallinales taxa from other parts of the world. Our study shows that psbA has considerable potential as a marker for this group, being easily amplified and considerably more variable than nSSU. Combined analyses using both markers provide significant support for relationships at both distal and terminal nodes of the analysis. Our analysis supports the monophyly of all three families currently defined in Corallinales: the Sporolithaceae, Hapalidiaceae and Corallinaceae, and indicates cryptic speciation in Mesophyllum and Spongites.

Mesophyllum incisum (Corallinaceae, Rhodophyta) in Southern Australia: Implications for generic and specific delimitation in the melobesioideae

Detailed morphological, anatomical and systematic studies of southern Australian populations and the designated lectotype of Mesophyllum incisum (Corallinaceae, Rhodophyta) have shown that several growth-forms occur and the filamentous core in dorsiventrally organized parts of the thallus can vary from coaxial to noncoaxial. Spermatangia are simple and develop centripetally on the chamber floor and roof; initials are overlain by “protective” cells during early stages of development. One or possibly several independent fusion cells may develop within female conceptacles after karyogamy. Tetrasporangial conceptacles are initiated from filaments containing elongate subterminal cells, and pore canals of mature conceptacles are lined by distinctive cells that differ in shape from other roof cells. These results have led to a reconsideration of the delimitation of Mesophyllum as a genus and to differences between M. incisum and the type species, M. lichenoides. A description of the species is provided along wit...

An account of the Hapalidiaceae (Corallinales, Rhodophyta) in south-eastern Australia

This paper provides the first monographic account of south-eastern Australian representatives of the Hapalidiaceae (Corallinales, Rhodophyta). The Hapalidiaceae includes those Corallinales whose tetrasporangia produce zonately arranged spores, and whose tetrasporangia/bisporangia are borne in conceptacles, produce apical plugs, develop beneath multiporate plates or roofs, and are not enclosed individually within calcified sporangial compartments. The Hapalidiaceae contains the subfamilies Choreonematoideae, Melobesioideae and Austrolithoideae, all formerly placed in the Corallinaceae sensu lato. The Choreonematoideae is represented in south-eastern Australia by a single species, Choreonema thuretii. The Melobesioideae is represented by five genera (Melobesia, Lithothamnion, Phymatolithon, Mesophyllum, Synarthrophyton) and eight species. Synarthrophyton pseudosorus sp. nov. is newly described. The presence of tetrasporangial conceptacles occurring in irregularly shaped dense clusters that contain both discrete conceptacles and fused groups of conceptacles delimits this species from all other species of Synarthrophyton. Morphological and anatomical accounts are provided, including keys, information on distribution, habitat and nomenclature. Brief biogeographic comparisons between south-eastern Australia and neighbouring regions are also made.

The Sporolithaceae (Corallinales, Rhodophyta) in south-eastern Australia: taxonomy and 18S rRNA phylogeny

Abstract The family Sporolithaceae (Corallinales, Rhodophyta) is represented in south-eastern Australia by two species: Heydrichia homalopasta and Sporolithon durum. Morphological and anatomical accounts are provided, including a key to species, and information on distribution, seasonality, habitat and nomenclature. Analyses of characters previously proposed for the delimitation of genera within the Sporolithaceae show similarities, overlaps or uncertainties for most character states. The presence of an involucre surrounding the tetrasporangial compartments in Heydrichia (and the absence of an involucre in Sporolithon) has proven a useful and stable character in delimiting these genera. Data from south-eastern Australian collections of H. homalopasta have also shown that features relating to tetrasporangial compartments are useful in delimiting H. homalopasta from other species of Heydrichia. These include the presence of solitary tetrasporangial compartments and the absence of successive tetrasporangia. New 18S rRNA sequence data from S. durum and H. homalopasta were combined with selected published sequences of coralline red algae. All phylogenetic reconstruction methods resolved H. homalopasta and H. woelkerlingii as sibling taxa in a strongly supported clade. Molecular data are consistent with the known morphological data and with recognition of H. homalopasta as a distinct species. Phylogenetic reconstructions consistently placed Sporolithon and species of Heydrichia in a strongly supported clade with Rhodogorgon carriebowensis, a species generally regarded as belonging to a separate order (Rhodogorgonales). This result is inconsistent with known morphological and reproductive features.

The Corallinaceae, subfamily Mastophoroideae (Corallinales, Rhodophyta) in south-eastern Australia

The first monographic account of the south-eastern Australian representatives of the Corallinaceae, subfamily Mastophoroideae (Corallinales, Rhodophyta) is presented. The Mastophoroideae contains eight extant genera, four of which [Hydrolithon, Mastophora, Neogoniolithon, Pneophyllum] were confirmed to occur in south-eastern Australia. Hydrolithon is represented by six species (H. farinosum, H. improcerum, H. munitum, H. onkodes, H. rupestre and H. samoense). Pneophyllum is represented by three species (P. coronatum, P. fragile and P. submersiporum) while Mastophora and Neogoniolithon are represented by a single species each (Mastophora pacifica and Neogoniolithon brassica-florida). Morphological and anatomical accounts are provided, including keys to genera and species, comparisons with related south-eastern Australian mastophoroid species, information on distribution, seasonality, habitat and nomenclature. Brief biogeographical comparisons between south-eastern Australia and other Australasian regions are also made.

The Genus Amphiroa (Lithophylloideae, Corallinaceae, Rhodophyta) from the Temperate Coasts of the Australian Continent, Including the Newly Described A. klochkovana

Harvey A.S., Woelkerling W.J. and Millar A.J.K. 2009. The genus Amphiroa (Lithophylloideae, Corallinaceae, Rhodophyta) from the temperate coasts of the Australian continent, including the newly described A. klochkovana. Phycologia 48: 258–290. DOI: 10.2216/08-84.1 Studies of Amphiroa (Lithophylloideae, Corallinaceae, Rhodophyta) from the temperate coasts of Australia provide new evidence that differences in tetrasporangial conceptacle pore canal anatomy are diagnostically significant in delimiting species within the genus. Differences in overall morphology and genicular anatomy are also reliable for delimiting species. These data are supported by examination of relevant type specimens. Four species occur in temperate Australian waters. Three (Amphiroa anceps, Amphira beauvoisii, and the newly described Amphiroa klochkovana) occur in southeastern Australia, and three (A. anceps, A. beauvoisii, and Amphiroa gracilis) occur in southern and southwestern Australia. Comparisons of A. beauvoisii and A. anceps have shown that they cannot be separated at species level morphologically but clearly differ in tetrasporangial conceptacle pore canal anatomy. This has important flow-on implications concerning specimen identification, reported geogeographic distribution and putative heterotypic synonymy of the two species. Relevant historical data, a species key and a synoptic description of Amphiroa also are included.

The genus Lithophyllum (Lithophylloideae, Corallinaceae, Rhodophyta) in south-eastern Australia, with the description of L. riosmenae, sp. nov.

The genusLithophyllum(Lithophylloideae, Corallinaceae, Rhodophyta) is represented by six species in south- eastern Australia L. chamberlainianum Woelkerling & Campbell, L. corallinae (Crouan & Crouan) Heydrich,L. cuneatum Keats,L.pustulatum(Lamouroux)Foslie,L.riosmenae,sp.nov.,andL.stictaeforme(AreschouginAgardh)Hauck.Fourof these taxaare commonlyfound inAustralia, whereasL.cuneatumwas previouslyknown onlyfromFiji andL. riosmenaeis newly described. Morphological and anatomical accounts are provided, including keys, information on distribution, nomenclature and habitat in south-eastern Australia. South-eastern Australian species are primarily delimited on characters relating to tetrasporangial conceptacles and the presence/absence of a semi-endophytic habit. Ten species of Lithophyllum are now confirmed to occur in Australia and their diagnostic characters are detailed. Confirmed Australian species ofLithophyllumare primarily delimited on characters relating to tetrasporangial conceptacles, the presence/absence of a semi-endophytic habit and the growth-form. Biogeographic comparisons between south-eastern Australia and other Australian biogeographic regions are also made. Eight species of Lithophyllum are known to occur in southern Australia, three in tropical eastern Australia and three in subtropical western Australia. Southern and south-eastern Australia show major overlap, with five species occurring in both regions. L. pustulatum and L. stictaeformae are widely distributed, having been confirmed to occur in eastern tropical, western subtropical, warm temperate and cold temperate waters within Australia.

CONCEPTACLE STRUCTURE OF THE PARASITIC CORALLINE RED ALGA CHOREONEMA THURETII (CORALLINALES) AND ITS TAXONOMIC IMPLICATIONS1

The major diagnostic features for erecting the red algal subfamily Choreonematoideae (Corallinales) were a combination of 1) absence of both cell fusions and secondary pit connections, 2) conceptacle roof and wall comprised of a single cell layer, and 3) presence of tetrasporangial pore plugs within a uniporate conceptacle in the monotypic taxon Choreonema thuretii (Bornet) Schmitz. Because this alga is a parasite, the absence of secondary cell connections is most likely an adaptation to a reduced thallus. This study shows that all conceptacles are not composed of a file of cells but rather a single layer of epithallial cells that are underlain by a thick layer of calcified acellular material; both epithallial cells and the calcified layer are produced by peripheral sterile cells. Although the outermost tetrasporangial pore canal is uniporate, there is a calcified acellular multiporate plate recessed just below the rim. The plate is produced by interspersed sterile cells and is continuous with the calcified layer supporting the conceptacle. These unique structures are likely due to parasitism rather than to the ancestral state. Based on these results and a reexamination of published micrographs depicting lenticular cells in Austrolithon intumescens Harvey et Woelkerling, we propose that both subfamily Choreonematoideae and Austrolithoideae are closely allied with subfamily Melobesioideae. This distant relationship to its host (Corallinoideae) plus a combination of unique conceptacle and unusual type of parasitism indicates that C. thuretii is an alloparasite and that it is likely the most ancient red algal parasite studied to date.

Lectotypification and epitypification of the type species of Amphiroa, A. tribulus (Lithophylloideae, Corallinaceae, Rhodophyta)

Woelkerling W.J. and Harvey A. 2012. Lectotypification and epitypification of the type species of Amphora, A. tribulus (Lithophylloideae, Corallinaceae, Rhodophyta). Phycologia 51: 113–117. DOI: 10.2216/11-75.1