Conceptacle production and life-history sequences were investigated in the simple crustose coralline species Pneophyllum myriocarpum, P. lobescens, P. plurivalidum and P. zonale in crusts growing in running sea-water in the laboratory. Conceptacle production was influenced by water temperature, daylength and photon flux densities. The presence of a Polysiphonia-type life history was confirmed in P. myriocarpum and P. lobescens and the presence of a self-perpetuating bisporangial life history was confirmed in P. lobescens, P. plurivalidum and P. zonale.
A redescription is given of Lithophyllum crouanii Foslie and of its structure, taxonomy and ecology in the British Isles. Due to a misidentification by Foslie, which was perpetuated by Rosenvinge, Suneson and Adey among others, the species has become known as L. orbiculatum (Foslie) Foslie. The origins of the nomenclatural and taxonomic confusion that has arisen as a result of Foslie's misidentification are fully documented and the relationship between L. crouanii and L. orbiculatum is discussed.
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.
AbstractPneophyllum amplexifrons (Harvey) comb. nov. is an epiphytic crustose coralline alga (Rhodophyta, Corallinaceae) of the subfamily Mastophoroideae. It occurs commonly in northern Natal, South Africa and is particularly abundant on intertidal populations of the seagrass Thalassodendron ciliatum (Forsskaring;l) den Hartog. It agrees well with the type specimen of Melobesia amplexifrons Harvey. A germination disc with 8 central cells is present, as usually seen in Pneophyllum. The roof of the tetrasporangial conceptacle forms from filaments surrounding and filaments interspersed among sporangial initials. A pore canal lined with numerous small cells confirms that the species pertains to the mastophoroid genus Pneophyllum.Two diagnostic features of P. amplexifrons are humps of uncalcified filaments at the thallus surface and tapered pore canals in the tetrasporangial conceptacles, lined with small, upward-pointing, non-protruding filaments.Comparison with syntypes of Lithophyllum pseudolichenoides Heydrich shows this species to be conspecific and it is subsumed in Pneophyllum amplexifrons.
Keats D.W., Maneveldt G.W., Baba M., Chamberlain Y.M. and Lewis J.E. 2009. Three species of Mastophora (Rhodophyta: Corallinales, Corallinaceae) in the tropical Indo-Pacific Ocean: M. rosea (C. Agardh) Setchell, M. pacifica (Heydrich) Foslie, and M. multistrata, sp. nov. Phycologia 48: 404–422. DOI: 10.2216/08-101.1.Three species of Mastophora (Corallinaceae, Corallinales, Rhodophyta) were found in extensive studies of non-geniculate coralline algae in various areas of the tropical Indo-Pacific, including French Polynesia, Fiji, Ryukyu Islands (Japan), and Taiwan. Two species are delicate and leafy but are distinguishable on morphological grounds. Mastophora rosea plants are taeniform, dichotomously branched, and weakly calcified and have rolled margins. Their thalli show very little secondary growth, with only occasional small round patches at the surface. Tetrasporangial and carposporangial conceptacles are very high (330–640 μm) and dome-shaped to almost spherical. Mastophora rosea plants collected during this study stand out in the water because of their bluish-purple colour. Mastophora pacifica has more strongly calcified thalli that are irregularly branched, with abundant secondary growth and the development of loosely attached, crispy layers. Tetrasporangial and carposporangial conceptacles are conical (280–550 μm high). Thallus colour in M. pacifica varies substantially depending on where it is growing, ranging from violet brown to dark red to greyish ruby, but are mostly pale-pink to reddish-purple in their submerged living state. Mastophora multistrata sp. nov. plants are hard and robust. Their thalli are made up of tightly packed layers that are evident only in section. Tetrasporangial conceptacles are generally low (315–490 μm high) and dome-shaped. In their living state, M. multistrata plants are usually deep-purple plum coloured.
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.
A new genus, Exilicrusta, and species, E. parva, of crustose coralline Rhodophyta are described from the British Isles. Exilicrusta has multiporate tetrasporangial conceptacles and cell fusions and therefore pertains to the subfamily Melobesioideae. It has a dimerous thallus like the genus Melobesia but differs in gametangial/carposporangial reproductive features. Exilicrusta parva is found growing together with Lithothamnion sonderi and both species have flared epithallial cells, as have all species of Lithothamnion. Exilicrusta differs from Lithothamnion, however, in having a dimerous as opposed to a monomerous thallus, and in the structure of its gametangial/carposporangial reproductive bodies. Lithothamnion sonderi is compared with its holotype specimen.
Lithophyllum capense Rosanoff (Rhodophyta, Corallinaceae) was described on the basis of herbarium specimens in Lamouroux's and Lenormand's herbaria in Caen, France. The specimens were epiphytic on Gelidium sp. from The Cape of Good Hope, South Africa. The structure and systematics of the lectotype and paratype specimens are compared with material collected recently in South Africa. The plants have markedly prominent, multiporate tetrasporangial conceptacles and belong to the subfamily Melobesioideae. The presence of monomerous growth, a single layer of non-flared epithallial cells, subepithallial initials that are as long as or longer than subtending cells and simple spermatangial systems on the floor and walls of male conceptacles place this species in the genus Mesophyllum: comparison with other known species of this genus shows that Mesophyllum capense (Rosanoff) comb. nov. is a distinct species with a distribution restricted, as far as is known, to South Africa. Lithophyllum capense Rosanoff (Rhodophyta, Corallinaceae) a été décrit sur la base de spécimens conservés dans les herbiers Lamouroux et Lenormand, à Caen, en France. Les spécimens étaient épiphytes sur Gelidium sp. du cap de Bonne Espérance, en Afrique du Sud. La structure et la systématique des spécimens lectotype et paratype sont comparées avec celles de matériel récolté récemment en Afrique du Sud. Les thalles ont des conceptacles à tétrasporocystes multiporés, fortement saillants et appartiennent à la sous-famille Melobesioideae. La présence d'une croissance monomérique, une unique couche de cellules epithéliales non-évasées, des initiales subépithélliales aussi longues ou plus longues que les cellules qui les sous-tendent et des systèmes reproducteurs mâles simples sur le fond et les parois des conceptacles mâles entraînent le placement de cette espèce dans le genre Mesophyllum : la comparaison avec les autres espèces connues de ce genre montre que Mesophyllum capense (Rosanoff) comb. nov. est une espèce distincte avec une distribution restreinte, dans l'état actuel des connaissances, à l'Afrique du Sud.
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