D. W. Keats

University of the Western Cape

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Y. M. Chamberlain

University of Portsmouth

Gavin W. Maneveldt

University of the Western Cape

D. H. Steele

Observatoire Océanologique de Banyuls-sur-Mer

G. Robin South

University of the South Pacific - Samoa Campus

Antoine De Ramon N’Yeurt

University of the South Pacific

Richard E. Norris

Botanical Research Institute of Texas

R.A. Townsend

Murdoch University

Robert G. Hooper

University of Warwick

Masasuke Baba

Marine Ecology Research Institute

Joseph Wakibia

Jomo Kenyatta University of Agriculture and Technology

Cooperative Institutions

University of the Western Cape

Memorial University of Newfoundland

Harvard University

James Cook University

University of Portsmouth

Ocean Institute

Australian Institute of Marine Science

University of the South Pacific

ARC Centre of Excellence for Coral Reef Studies

Australian Research Council

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Rhipilia penicilloides sp. nov. (Udoteaceae, Chlorophyta) from Fiji

Phycologia (1997)

Antoine De Ramon N’Yeurt D. W. Keats

AbstractRhipilia penicilloides sp. nov. (Udoteaceae, Chlorophyta) is described from the Fiji Islands, South Pacific. Adult thalli are characterized by a penicilloid capitulum of free, dichotomously branched siphons and an elongated corticated stipe arising from a multisiphonous rhizome-like mat or stolon, whereas juvenile stages possess an infundibular capitulum held together by abundant lateral tenaculiferous branch lets. The generic placement of the new species is debatable owing to its close affinities to both the genera Chlorodesmis and Rhipilia, but present evidence favors the latter.

Stipe (mycology)

Thallus

Stolon

10.2216/i0031-8884-36-2-172.1

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Citations (7)

The non-geniculate coralline algaeSynarthrophyton eckloniae(Foslie) comb. nov. andS. magellanicum(Foslie) comb. nov. (Rhodophyta) in South Africa including comparison with relevant types

European Journal of Phycology (1997)

D. W. Keats Y. M. Chamberlain

In continuing studies on the taxonomy of non-geniculate, coralline algae from South Africa, stipes of the kelp, Ecklonia maxima, in the subtidal zone of Western Cape Province, were frequently observed to be covered with rosy-pink encrusting coralline algae. The reproductive morphology and anatomy of these plants show that they belong to the subfamily Melobesioideae and the genus Synarthrophyton. The specimens agree closely with the holotype of Lithothamnion capense f. eckloniae described by Foslie on the basis of South African material. Synarthrophyton eckloniae is described in detail; the species appears to be endemic to Western Cape Province. Another crustose coralline alga from the subtidal zone of South Africa was found to be conspecific with a syntype of Lithothamnion magellanicum and the lectotype and isolectotype of Lithothamnion muelleri f. neglecta. These are now shown to conform to the generic concept of Synarthrophyton on the basis of their concordance with the characters of that genus. South African material of S. magellanicum is compared with the type specimen of Lithophyllum schmitzii with which it had been synonymized and it is concluded that the two species are distinct. It can be distinguished from type specimens of Lithothamnion lamellatum and L. chatamense, with which previous authors had suggested it might be conspecific, on the basis of anatomical characters, despite similarity in habit. The last two species have not been recorded in South Africa.

Coralline algae

Crustose

Red algae

Subfamily

10.1080/09541449710001719375

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Citations (19)

Three melobesioid crustose coralline red algae from South Africa: Leptophytum acervatum (Foslie) comb. nov., L. foveatum sp. nov. and L. ferox (Foslie) comb. nov

Phycologia (1994)

Y. M. Chamberlain D. W. Keats

AbstractThree common crustose coralline algae from South Africa are attributed to the genus Leptophytum of the subfamily Melobesioideae. Leptophytum acervatum and L. foveatum are epilithic or epizoic with thin, flat thalli and deeply sunken conceptacles. They are very similar in appearance but, in addition to different vegetative and reproductive anatomical features, L. acervatum grows mainly on loose stones, L. foveatum on bedrock, tunicate tests and shells. Leptophytum ferox is mainly epilithic but also grows round worm tubes. It is one of the most common intertidal crustose coralline species in South Africa and shows great variability in form, ranging from flat to extravagantly protuberant thalli.Leptophytum acervatum agrees well with the lectotype of Lithothamnion acervatum Foslie. Leptophytum ferox corresponds with the holotypes of Lithothamnion ferox Foslie and L. falsellum f. plicata Foslie, and the lectotype of L. prolixum Foslie; its relationship to L. falsellum Heydrich is discussed. The features distinguishing Leptophytum from other melobesioid genera are considered.

Crustose

Thallus

Coralline algae

Red algae

10.2216/i0031-8884-33-2-111.1

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Citations (31)

First report of the melobesioid alga (Corallinales, Rhodophyta) Mesophyllum incisum (Foslie) Adey in South Africa

South African Journal of Botany (1997)

D. W. Keats Gavin W. Maneveldt

Mesophyllum incisum is reported and studied for the first time in South Africa. It has a thallus surface (SEM) with Leptophytum-type epithallial cells. Tetra/bisparangial conceptacles are mound-like and lack a peripheral rim but have a flattened pore plate. The rosette cells surrounding the tetrasporangial pores are distinct from surrounding roof cells (SEM, surface view) in being narrower, and sunken below the level of the surrounding pore plate. The cells of filaments bordering the tetrasporangial conceptacle pore canal differ from the other roof cells within the pore plate in being more elongate, narrower, and often more densely staining. Pore canal filaments also generally contain fewer cells than the surrounding filaments of the pore plate and the pore canal is more-or-less parallel sided. Our material agrees closely with the species as reported in Australia.

Thallus

Rosette (schizont appearance)

10.1016/s0254-6299(15)30745-6

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Citations (15)

Taxonomic review based on new morpho-anatomical data of the algae Porolithon craspedium and P. gardineri (Corallinaceae, Corallinales, Rhodophyta), and comments on other taxa ascribed to the genus

Phytotaxa (2016)

Gavin W. Maneveldt D. W. Keats

Based on new studies of the types and of putative conspecific specimens from various localities in the Indian and Pacific oceans, Porolithon craspedium and Porolithon gardineri were reaffirmed as distinct species. Examining solely morpho-anatomical data, the types of P. castellum and P. marshallense were found to match the present-day diagnosis of P. craspedium and P. gardineri respectively. It is possible therefore that P. castellum and P. marshallense may respectively be conspecific with P. craspedium and P. gardineri. However, due to a lack of DNA sequencing of the type and/or ‘topotype’ specimens, formal synonymies cannot be proposed and we hope that this study can instead be used to facilitate future research. In contrast to other species from the genus, mature P. craspedium is massive and mountain-like, bearing broad individual to fused vertical columns, while P. gardineri is fruticose with narrow terete, loosely dichotomously branched, predominantly unfused protuberances. Species of Porolithon are ecologically very important and are now well established as principal cementers and primary reef frame-builders of coral reefs across the globe. Additionally, P. colliculosum and P. orbicularis where shown to conform instead to the current characterisation of Spongites and have here been duly transferred to that genus.

Morpho

Type specimen

10.11646/phytotaxa.289.1.1

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Citations (3)

Cell sloughing in the littoral zone coralline alga, Spongites yendoi (Foslie) Chamberlain (Corallinales, Rhodophyta)

Phycologia (1993)

D. W. Keats Albrecht Groener Y. M. Chamberlain

AbstractSpongites yendoi (Foslie) Chamberlain is an abundant non-geniculate coralline alga in the lower eulittoral zone along the south and west coast of South Africa, where it is associated primarily with the territorial, gardening limpet, Patella cochlear Born. In November 1990, June 1991 and November 1991, large patches of Spongites yendoi became white. Microscopic examination revealed that a surface layer was being shed, and that healthy living filaments were found below this sloughing layer. Unlike most corallines, which may shed an epithallial surface layer, S. yendoi was shedding from deep within the thallus, well below the layer of meristematic cells. A new layer of meristematic cells was regenerated below the layer which was being shed. The production of new sporangial conceptacles was observed at the same time. This type of cell sloughing could be a response to a physical phenomenon, a mechanism for preventing fouling, a means of discarding old conceptacles and grazer-damaged cells to prevent infection, or a means of preventing the thallus from becoming thick and weakened by undercutting.

Thallus

Sloughing

Limpet

10.2216/i0031-8884-32-2-143.1

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Citations (45)

Competitive relationships and coexistence in a guild of crustose algae in the eulittoral zone, Cape Province, South Africa

South African Journal of Botany (1994)

D. W. Keats Ian Matthews Gavin W. Maneveldt

A number of crustose, fleshy and coralline algae coexist in the eulittoral zone along the south-western coast of South Africa, in spite of potentially competing for the same limiting resource, space. A number of questions concerning coexistence among crustose algae were addressed in a study conducted at Holbaaipunt, in the southwestern Cape Province. To some degree, the crustose algae occur in different zones, and this may thus reduce competition. It was shown that non-transitive networks did not exist among the crustose algae at this site, so do not contribute to the coexistence of these crustose algae. While most species occur on rock substratum, one species occurs primarily on worm tubes and compacted calcareous material, suggesting that habitat heterogeneity within zones may contribute to the coexistence of these crustose species. Differential susceptibility to, and recovery from, disturbance may also contribute to coexistence. The thinnest species in the mid-lower eulittoral zone at this site, Spongites yendoi (Foslie) Chamberlain, dominates the space in spite of its position near the bottom of the overgrowth hierarchy. This may be because its thin thallus shows faster lateral growth and less susceptibility to disturbance than its thicker competitors. Thallus thinness may be maintained by the periodic deeplayer sloughing of a surface layer, as well as by heavy grazing by Patella cochlear Born. 'n Aantal kors-vleesagtigeen koralloïde alge kom saam in die eulittorale sone langs die suidwestelike kus van Suid Afrika voor ten spyte dat hulle vir dieselfde beperkbare hulpbron, ruimte, kompeteer. 'n Aantal vrae oor saambestaan tussen korsagtige alge is aangespreek in 'n studie by Holbaaipunt in die suidwestelike Kaap Provinsie. Tot 'n sekere mate kom die korsagtige alge in verskillende sones voor en dit mag kompetisie dus verminder. Nietransitiewe netwerke kom nie voor tussen die korsagtige alge by hierdie vindplek nie, dus dra dit nie by tot die saambestaan van hierdie korsagtige alge nie. Terwyl die meeste spesies op rotse voorkom, kom een spesie hoofsaaklik op wurmbuise en kompakte kalkagtige materiaal voor. Dit stel voor dat habitat heterogeniteit binne in sones mag bydra tot die saambestaan van hierdie korsagtige spesies. Gedifferensieerde vatbaarheid tot, en herstelling na, versteurings mag ook tot saambestaan bydra. Die dunste spesies in die middel onderste eulittorale sone by hierdie vindplek, Spongites yendoi (Foslie) Chamberlain, domineer die ruimte ten spyte van sy posisie naaan die bodem van die oorgroeisel-hiërargie. Dit mag miskien so wees omdat sy dun tallus vinniger laterale groei toon asook minder vatbaarheid tot versteurings in vergelyking met sy dikker kompeteerders. Tallusdunheid mag behou word deur die periodiese dieplaagskending van 'n oppervlaklaag asook die swaar weiding van Patella cochlear Born.

Crustose

Coralline algae

Thallus

10.1016/s0254-6299(16)30640-8

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Citations (26)

Depth-dependent reproductive output of the green sea urchin, Strongylocentrotus droebachiensis (O.F. Müller), in relation to the nature and availability of food

Journal of Experimental Marine Biology and Ecology (1984)

D. W. Keats D. H. Steele G. Robin South

Strongylocentrotus droebachiensis

Crustose

10.1016/0022-0981(84)90095-9

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Citations (94)

The effects of the experimental removal of green sea urchins and of ice-scour on sublittoral benthic macro-algal communities in eastern Newfoundland

D. W. Keats

The results of an urchin removal experiment which was conducted over a four year period at a site in Conception Bay, Newfoundland are reported. The experiment was carried out to determine how the benthic algal community at a heavily grazed sublittoral Newfoundland site, subjected to periodic ice scour, would respond to a reduction in grazing pressure. Three transects were selected: one from which urchins were removed manually; one from which urchins were removed using quicklime, and one as a control. Sampling was conducted within each of three depth ranges: 0-2m, the shallow macro-algal zone; 2-3m, the upper portion of the urchin dominated zone; and 6-9m, the middle portion of the urchin dominated zone. The occurrence of ice-scour during two out of four years of the study allowed an assessment of its effects on biomass, diversity, and species composition of the algal community. -- In the shallow zone (0-2m) urchins had no detectable effect on macroalgal biomass. Biomass, species composition and diversity were affected, however, by the occurrence and timing of ice-scour. In the absence of ice-scour, Alaria esculenta formed a canopy which shaded the substratum; few species coexisted, and diversity was low. Winter and spring ice scour, which was temporally and spatially patchy, removed the Alaria canopy and made available well lighted rocky substratum for colonization. Scoured patches were· colonized by annual algae, resulting in an increase in diversity. Biomass returned to pre-scour levels approximately 2 mo after scouring, but diversity remained high due to the persistence of several species of annual algae in patches among the unscoured Alaria. -- In the urchin dominated zone macro-algal biomass increased following urchin removal by both manual and quicklime techniques. The upper portion of the resulting communities became dominated by Alaria esculenta, with very few co-existing species. This dominance by Alaria was also typical of the shallow zone in years during which no ice-scour occurred. Below the zone of Alaria domination (2-3m) the community became dominate~ by Desmarestia aculeata, with many other co-existent species (including Agarum cribrosum, Alaria esculenta, and Laminaria digitata). -- Algal biomass in the control area was generally low, except during the summer of 1982, when an increase in both biomass and species richness occurred. The species composition, however, differed from that on the removal transects in that the control area was dominated by annual algae such as Acrothrix novaeangliae, Chordaria flagelliformis, Dictyosiphon foeniculaceus, Ectocarpus siliculosus, and Eudesme virescens. Alaria and Desmarestia aculeata were unimportant in this association because the algae recruited in the late spring and early summer, after the period of Alaria and Desmarestia recruitment. -- Urchin biomass in the control area was greatest at 2-3m. Density was greatest in the middle of the urchin dominated zone (6-9m), where numerous juveniles occurred in crevices, and among branched and undercut encrusting coralline algae. -- In addition to urchins, the herbivore guild in the study area consisted of six species of molluscs (Acmaea testudinalis, Lacuna vincta, Margarites helicinus, Ischnochiton alba, Tonicella marmorea, and T. rubra). Densities of Acmaea and the three chitons were greatest at 6-9m. Recruitment and density of the latter three species showed no detectable relationship with urchin removal. Recruitment of the annual Lacuna and Margarites occurred during the early autumn, in shallow water, particularly in the presence of macro-algae. Survival into the following spring was greatest on the macro-algae in the urchin removal areas.

Strongylocentrotus droebachiensis

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Algal biomass and diversity in the upper subtidal at a pack-ice disturbed site in eastern Newfoundland

Marine Ecology Progress Series (1985)

D. W. Keats G. Robin South D. H. Steele

Over a 5 yr period, the effect of physical disturbance by ice-scour on biomass, diversity and community composition in the shallow macro-algae zone of eastern Newfoundland was examined.In the absence of ice-scour, Alaria exculenta formed a canopy which shaded the substratum; few species CO-existed and diversity was low.Winter and spring ice-scour, which was temporally and spatially patchy, removed the A. esculenta and made well-lighted rocky substratum available for colonization.Scoured patches were colonized by annual algae, resulting in an increase in species diversity.Diversity was greater when patchy scouring occurred throughout the winter-spring period, than when scouring was more restricted.Several species of annual algae persisted in patches among the unscoured A. esculenta, so diversity remained high during the summer following scouring.

10.3354/meps025151

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Citations (35)