Content uploaded by Elizabeth Van der Merwe
Author content
All content in this area was uploaded by Elizabeth Van der Merwe on Jan 08, 2016
Content may be subject to copyright.
A preview of the PDF is not available
Heydrichia cerasina sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta) from the southernmost tip of Africa
Abstract and Figures
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 mu m thick); (4) tetra/bisporangial son 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 the distribution of spermatangial structures within male chambers is a feature that cannot be used to separate Heydrichia from Sporolithon, the only other genus in Sporolithales, although features of thallus construction and tetra/bisporangia continue to distinguish the genera. A key to the southern African species from the order Sporolithales is provided.
Figures - uploaded by Elizabeth Van der Merwe
Author content
All figure content in this area was uploaded by Elizabeth Van der Merwe
Content may be subject to copyright.
... Specimens for light microscopy were prepared following Maneveldt and van der Merwe (2012). In cell measurements, length denotes the distance between primary pit connections, and diameter the maximum width of the cell lumen at right angles to this. ...
Phymatolithopsis acervata comb. nov., and P. roseola sp. nov. (Hapalidiales, Rhodophyta) from South Africa with a comment on infraordinal classification Abstract: Phymatolithon acervatum is an encrusting, non-geniculate coralline alga from South Africa. While morpho-anatomical details of the species are well documented, no genetic analyses have been performed on P. acervatum. Here, we analyzed rbcL and psbA gene sequences, and they showed that two species were passing under the name Phymatolithon acervatum in South Africa. A partial rbcL sequence from the lectotype of Lithothamnion acervatum, basionym of P. acervatum, showed to which species the specific epithet applies, and furthermore that both species belong in Phymatolithopsis. We transfer Phymatolithon acervatum to Phymatolithopsis, as Phymatolithopsis acervata comb. nov., and propose Phymatolithopsis roseola sp. nov. These species overlap in morpho-anatomy, habitat and distribution and can only be distinguished based on DNA sequences. Previous misinterpretations of conceptacle development are corrected for species of Phymatolithopsis. The main character used to define the family Mesophyllumaceae is shown to have arisen several times in independent lineages in the order Hapalidiales. At present, only one family, Hapalidiaceae, thus merits recognition in the Hapalidiales.
... Taxonomic identification of the thalli from each depth was based on morphoanatomical analyses using the histological methods described in [20] and comparison to known species of the region [21][22][23][24]. ...
Red coralline algae are the deepest living macroalgae, capable of creating spatially complex reefs from the intertidal to 100+ m depth with global ecological and biogeochemical significance. How these algae maintain photosynthetic function under increasingly limiting light intensity and spectral availability is key to explaining their large depth distribution. Here, we investigated the photo- and chromatic acclimation and morphological change of free-living red coralline algae towards mesophotic depths in the Fernando do Noronha archipelago, Brazil. From 13 to 86 m depth, thalli tended to become smaller and less complex. We observed a dominance of the photo-acclimatory response, characterized by an increase in photosynthetic efficiency and a decrease in maximum electron transport rate. Chromatic acclimation was generally stable across the euphotic-mesophotic transition with no clear depth trend. Taxonomic comparisons suggest these photosynthetic strategies are conserved to at least the Order level. Light saturation necessitated the use of photoprotection to 65 m depth, while optimal light levels were met at 86 m. Changes to the light environment (e.g. reduced water clarity) due to human activities therefore places these mesophotic algae at risk of light limitation, necessitating the importance of maintaining good water quality for the conservation and protection of mesophotic habitats.
... For light microscopy, samples were prepared according to [25], with few modifications. The dry coralline algae crusts were decalcified in 10% nitric acid, rinsed in water, dehydrated in a sequence of 70%, 90%, and 100% ethanol solutions (60 min each), and immersed in Leica Historesin infiltration medium (12 h). ...
The aim of this study was to elucidate the taxonomy of the common but overlooked epiphytic coralline algae species from shallow reefs and seagrass meadows of the Abrolhos Archipelago, Brazil. Two thin (two vegetative cells thick) epiphytic coralline species were recorded: Lithophyllum epiphyticum sp. nov. and Hydrolithon farinosum. Molecular analysis from psbA genetic marker confirmed the position of L. epiphyticum into Lithophylloideae and revealed a phylogenetic relationship with an undescribed Lithophyllum from Italy. Thin thallus (2–3 cells thick) and cells lining the pore of tetrasporangial conceptacles protruding laterally occluding the canal, either partially or totally, are its main diagnostic characteristics. Hydrolithon farinosum is herein described in detail for Brazil, and its worldwide distribution is then discussed.
... Specimens for light microscopy were prepared following Maneveldt and van der Merwe (2012). For cell measurements, length denotes the distance between primary pit connections, and diameter denotes the maximum width of the cell lumen at right angles to the length. ...
Phylogenetic analyses of rbcL gene sequences and of concatenated rbcL, psbA and SSU rRNA gene sequences resolved the generitype of Lithothamnion, L. muelleri, in a clade with three other southern Australian species, L. kraftii sp. nov., L. saundersii sp. nov. and L. woelkerlingii sp. nov. Cold water boreal species currently classified in Lithothamnion and whose type specimens have been sequenced are transferred to Boreolithothamnion gen. nov., with B. glaciale comb. nov. as the generitype. The other species are B. giganteum comb. nov., B. phymatodeum comb. nov., and B. sonderi comb. nov., whose type specimens are newly sequenced, and B. lemoineae comb. nov., B. soriferum comb. nov., and B. tophiforme comb. nov., whose type specimens were already sequenced. Based on rbcL sequences from the type specimens of Lithothamnion crispatum, L. indicum, and L. superpositum, each is recognized as a distinct species and transferred to the recently described Roseolithon as R. crispatum comb. nov., R. indicum comb. nov., and R. superpositum com. nov., respectively. To correctly assign species to these three genera based only on morpho-anatomy, specimens must have multiporate conceptacles and some epithallial cells with flared walls. The discussion provides examples demonstrating that only with phylogenetic analyses of DNA sequences can the evolution of morpho-anatomical characters of non-geniculate corallines be understood and applied at the correct taxonomic rank. Finally, phylogenetic analyses of DNA sequences support recognition of the Hapalidiales as a distinct order characterized by having multiporate tetra/bisporangial conceptacles, and not as a suborder of Corallinales whose tetra/bisporangial conceptacles are uniporate.
... light intensity, diurnal and nocturnal light cycle, etc) we used AI Vega lights (Aqua Illumination, Pennsylvania, USA). Adult Specimens were identified from morphological and reproductive characters (SupplementaryFigure 1)observed in sections prepared using methods detailed inManeveldt and Van Der Merwe, 2012. ...
... Rhodolith sphericity was determined by measuring the longest, intermediate and shortest axes [45,46], and the triangular diagram plotting spreadsheet (TRI-PLOT) was used to separate ellipsoidal, discoidal or spheroidal shapes [46]. Species identification of crusts on the outermost surface of rhodoliths was conducted solely through the morpho-anatomical observation of histological sections (Supplementary Material Figure S1) of fertile material [44,[47][48][49][50]. A permutational multivariate analysis of variance (PERMANOVA) with the software Primer (v.6) + PERMANOVA was used to evaluate possible significant differences in rhodolith size between the different sites and depths. ...
A Margem Continental Amazônica (MCA) e Bacia Sergipe-Alagoas (SEAL) se destacam pelo desenvolvimento de formações carbonáticas/siliciclásticas, desde períodos geológicos passados até o presente. O foco deste estudo foi avaliar a evolução das estruturas recifais da MCA e rodolitos da Bacia SEAL após o Último Máximo Glacial (LGM). Com os resultados obtidos, foi possível definir a estrutura das formações recifais; as fácies dominantes nas amostras estudadas, caracterizando-as nas distintas idades de sua formação. Três principais formações foram reconhecidas em diferentes faixas de profundidade: bancos de rodolitos, concreções carbonáticas e ‘recifes’. Um total de 22 morfo-taxons de algas vermelhas (rodofíceas) foram identificadas nos locais de estudo. A transição entre a plataforma externa e a quebra da plataforma no Setor Norte da MCA traz consigo uma série de estruturas proeminentes de alto relevo. Os topos destas feições estão entre 110-165 m de profundidade e parecem ter se originado durante o baixo nível do mar (NM), através da erosão dos arenitos Pleistocênicos. Os depósitos carbonáticos e siliciclásticos acumulados no topo dessas feições durante o LGM e deglaciação precoce foram gradualmente submersos pela elevação do NM e pela subsidência. Uma fina camada de organismos incrustantes (algas coralináceas, esponjas, briozoários e serpulídeos) coloniza atualmente a maioria dessas superfícies e contribui para a agregação de uma camada carbonática fina com siliciclásticos de grão fino. O Setor Central, em frente à foz do rio, está associado ao acúmulo de sedimentos a longo prazo e carece de uma ruptura na plataforma. No entanto, comunidades bentônicas vivas ocorrem em afloramentos rochosos. O Setor Sul é menos influenciado pela pluma do rio e inclui uma plataforma mais rasa e um cânion proeminente. Os afloramentos rochosos do Pleistoceno a 180 m carregam coberturas finas de uma comunidade bentônica dominada por esponjas e algas coralináceas, que são responsáveis pelo acúmulo de um depósito fino de bioclastos, areia de quartzo e lama sobre o substrato rochoso. Assim, os ‘recifes’ da plataforma externa e a margem mesofótica da Amazônia são tipicamente rochas antigas erodidas, colonizadas por organismos incrustantes durante o LGM e deglaciação formando uma camada carbonática, que agora suporta uma comunidade mesofótica. Operações com Veículo Operado Remotamente e a amostragens com rede de arrasto de fundo na Bacia SEAL revelaram a ocorrência de bancos de rodolitos entre 25-54 m de profundidade. Nas profundidades mais rasas, rodolitos ramificados (maërl) aparecem nos leitos de ondulações (ripples) e outros rodolitos não ramificados ocorrem associados a corais e esponjas circundadas por areia bioclástica. Rodolitos também ocorrem em manchas e alguns são fundidos entre 30-39 m de profundidade. Em profundidades maiores (40- 54 m) a abundância de rodolitos aumenta e ocorre associada a macroalgas carnosas, localmente alguns são maërl e outros são parcialmente enterrados por sedimentos de granulação fina. Duas fases de crescimento podem ser distinguidas em alguns rodolitos. Os núcleos apresentaram idades entre 1.600-1.850 anos, enquanto as camadas externas eram muito mais jovens (180-50 anos). As camadas de crescimento pareciam ter sido separadas por um longo período de enterramento no sedimento do fundo do mar.
Using examples from specimens previously ascribed to the genus Spongites, we show that a high degree of cryptic and pseudo-cryptic diversity exist in the non-geniculate coralline red algae from South Africa. We argue that the the true diversity may be as high as 10 times what we currently recognise based solely on morpho-anatomy.
The presentation questions the role of alpha taxonomy in the light of growing reliance on DNA sequences for accurate species identification. We argue that there is still an important place for alpha taxonomy, but that this is best achieved through what has been, more recently, referred to as an Integrated Taxonomic Approach (ITA, Gabrielson et al. 2011), which firstly utilizes DNA sequences from both type and field-collected specimens and then attempts to produce the morpho-anatomical description(s).
The presentation poses a question about the relevance of alpha taxonomy in the age of DNA sequences. We argue that alpha taxonomy still has an important role to play, but is best achieved through what has been, more recently, referred to as an Integrated Taxonomic Approach (ITA, Gabrielson et al. 2011), which firstly utilizes DNA sequences from both type and field-collected specimens and then attempts to produce the morpho-anatomical description(s).
Heydrichia groeneri sp, nov., the second recorded species of the genus, is described from western Cape Province, South Africa, and southern Namibia. It is ascribed to the genus Heydrichia on the basis of a type of sporangial development in which the successive production of tetrasporangia results in multiple sporangial stalk cells. It differs from H. woelkerlingii by having a much thinner thallus, broader thallus cells, smaller tetrasporangia and tetrasporangial chambers, and fewer cells in the filaments surrounding the chamber walls. In addition, H. groeneri appears to have a somewhat wider distribution in southern Africa than H. woelkerlingii. A key to the South African species of Sporolithaceae is provided.
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.
During the past five years, Caribbean-West Indian algal ridges have been examined by aerial reconnaissance, surface investigation and coring with C¹⁴ dating.
In this paper the algal ridges of this area are briefly described and their quantitative distribution by region throughout the area is determined and mapped. Seasonal trade wind constancy and strength is diagrammed and the relationship with algal ridge development examined.
Algal ridges appear where the minimum seasonal wind effect index (constancy × strength) exceeds 180 (60% × 3.0 Bf.) and they would dominate reef systems where seasonal minimum wind effect exceeds 320 (80% × 4.0 Bf.). The strong development of algal ridges in Holandes Cays in Panama is anomalously high for that region. It would appear that local shore and reef morphology and orientation can exert considerable control on wave action and can markedly alter local potential for algal ridge development.
Crustose corallines were collected from a wide range of depths (intertidal to about 300 m) throughout the Hawaiian Archipelago. A total of 25 species in 10 genera are recognized on the basis of habit, anatomy, morphology, and ecology, including one new genus and 10 new species. Generic and specific keys for the differentiation of the Hawaiian crustose corallines are also provided. The ecology of each species, in terms of depth distribution and habitat, is also given, and the potential use of these plants in determining paleoenvironments in the Hawaiian Neogene is discussed. The Caribbean and Hawaiian crustose coralline floras are briefly compared. The large number of "pair species" and the parallelism in subfamily, generic, and "pair species" ecology indicate that coralline evolution is very slow. The crustose corallines are potentially excellent paleoecological indicators for the Tertiary.
Critical studies of relevant generitype specimens and of numerous southern Australian populations have led to the conclusions that diff erences in trichocyte occurrence and arrangement, basal region organization and cell size cannot be used to delimit genera within the Spongites complex (Corallinaceae, Rhodophyta). Hydrolithon Foslie and Porolithon Foslie therefore are treated as heterotypic synonyms of Spongites and Pseudolithophyllum sensu Adey is also considered congeneric with Spongites. Solitary trichocytes, vertical rows of trichocytes and horizontal rows or fields of trichocytes all can occur within single plants. Plants otherwise identical may or may not produce trichocytes. Both unistratose and multistratose basal regions can develop in primary portions of the same plant and abrupt transitions from one to the other can occur. Cell sizes of generitype specimens overlap and a broad continuum of cell sizes occur in southern Australian plartts. The circumscription of Spongites has been altered to take account of these results and the relationships of Spongites to other genera of nongeniculate Corallinaceae are then considered. Relevant historical and nomenclatural data are included.
Critical studies of relevant generitype specimens and of numerous southern Australian populations have led to the conclusions that diff erences in trichocyte occurrence and arrangement, basal region organization and cell size cannot be used to delimit genera within the Spongites complex (Corallinaceae, Rhodophyta). Hydrolithon Foslie and Porolithon Foslie therefore are treated as heterotypic synonyms of Spongites and Pseudolithophyllum sensu Adey is also considered congeneric with Spongites. Solitary trichocytes, vertical rows of trichocytes and horizontal rows or fields of trichocytes all can occur within single plants. Plants otherwise identical may or may not produce trichocytes. Both unistratose and multistratose basal regions can develop in primary portions of the same plant and abrupt transitions from one to the other can occur. Cell sizes of generitype specimens overlap and a broad continuum of cell sizes occur in southern Australian plartts. The circumscription of Spongites has been altered to take account of these results and the relationships of Spongites to other genera of nongeniculate Corallinaceae are then considered. Relevant historical and nomenclatural data are included.
Critical studies of material from the Spermonde Archipelago, south-western Sulawesi, Indonesia, and relevant type material have provided a range of morphological and anatomical characters for species delimitation within the genus Sporolithon (Corallinales, Rhodophyta). Sporolithon is referred to a new family, the Sporolithaceae fam. nov. This family is characterized by the presence of cruciately cleaved tetrasporangia and the absence of tetrasporangial conceptacles. Detailed anatomical observations of the reproductive and vegetative structures are presented. The type collections of all species of Sporolithon reported from Indonesia were examined, and, where necessary, types have been designated. The relationships of Archaeolithothamnion erythraeum (Roth pletz) Foslie to Sporolithon molle (Heydrich) Heydrich and Sporolithon ptychoides Heydrich, and the misinterpretations that have led to the present confusion surrounding the taxonomic position of the genus Sporolithon, are discussed.
Studies of tetrasporangial conceptacle development and anatomy have led to the conclusion that Spongites and Hydrolithon (of which Porolithon is considered to be a heterotypic synonym) are distinct genera of the Corallinaceae (Rhodophyta). In Australian populations of Hydrolithon reinboldii (Weber van Bossee et Foslie) Foslie, the type species of Hydrolithon, and Porolithon onkodes (Heydrich) Foslie, the type species of Porolithon, the tetrasporangial conceptacle pore canal is lined by a ring of conspicuous, elongate cells that arise from filaments interspersed amongst sporangial initials, do not protrude into the canal, and are oriented more or less perpendicularly to the roof surface. In Spongites fruticulosus Kutzing, the type species of Spongites, the pore canal is lined by cells that arise from peripheral roof filaments, protrude into the canal and are oriented more or less parallel to the roof surface. Tetrasporangial conceptacle development in Hydrolithon reinboldii and Porolithon onkodes is compared with that of Spongites fruticulosus, and Porolithon onkodes is transferred into Hydrolithon. Generic classification within the subfamily Mastophoroideae is discussed, and relevant historical and nomenclatural data are also included.