Yvonne M. Chamberlain

PNEOPHYLLUM CONICUM (DAWSON) COMB. NOV. (RHODOPHYTA, CORALLINACEAE), A WIDESPREAD INDO-PACIFIC NON-GENICULATE CORALLINE ALGA THAT OVERGROWS AND KILLS LIVE CORAL

A common Indo-Pacific non-geniculate coralline alga was studied in Fiji, French Polynesia, Ryukyu Islands (Japan) and South Africa, and compared with an isotype of Hydrolithon concium. The isotype contains only bisporangial material, but it is concordant with the material studied in the tropical IndoPacific. The species is transferred to Pneophyllum on the basis of its agreement with the characters of that genus. Pneophyllum conicum is characterised by a monomerous thallus with a predominantly coaxial medulla, the absence of uncalcified outgrowths, trichocytes that are arranged horizontally into circular fields, the absence of protruding tetra/bisporangial pore canal filaments, the presence of papillae lining the tetra/bisporangial pore canal, tetra/bisporangia distributed peripherally about a large central columella, tetra/bisporangial conceptacles low conical with a chamber that measures 220-400 μιη in diameter, the absence of a calcified pore dome and hyaline collar surrounding the tetra/bisporangial pore, and conceptacles that are shed on senescence. Pneophyllum conicum is the only non-geniculate coralline that we have observed to regularly and commonly overgrow and kill live coral, especially taxa with small polyps and relatively smooth colonies.

Two melobesioid coralline algae (Rhodophyta, Corallinales), Mesophyllum erubescens (Foslie) Lemoine and Mesophyllum funafutiense (Foslie) Verheij from Sodwana Bay, South Africa

Two species of the coralline red algal genus Mesophyllum (Corallinaceae, Melobesioideae) are reported from the southernmost coral reefs in the western Indian Ocean at Sodwana Bay, Natal, South Africa. Specimens attributed to Mesophyllum erubescens (Foslie) Lemoine were compared with the type specimens of Lithothamnion erubescens Foslie and L. erubescens f. madagascariensis Foslie [= M. madagascariensis (Foslie) Adey]. The comparison showed that the local material and the type specimens are all conspecific, confirming previous suggestions that M. madagascariensis should be subsumed in M. erubescens. Mesophyllum funafutiense (Foslie) Verheij was also recorded. These species are distinguishable on the basis of the structure of the roof and the pore of the tetrasporangial conceptacles, and on the size of tetrasporangial conceptacles and tetrasporangia.

AN SEM-BASED ANALYSIS OF THE MORPHOLOGY, ANATOMY, AND REPRODUCTION OF LITHOTHAMNION TOPHIFORME (ESPER) UNGER (CORALLINALES, RHODOPHYTA), WITH A COMPARATIVE STUDY OF ASSOCIATED NORTH ATLANTIC ARCTIC/SUBARCTIC MELOBESIOIDEAE1

Lithothamnion tophiforme (Esper) Unger is a dominant, arctic, saxicolous species that extends southward, albeit with reduced cover, into the deeper colder waters of the North Atlantic subarctic, where it also occurs in significant rhodolith deposits with L. glaciale. The external appearance of L. tophiforme is distinctive, but typification, anatomy, reproduction, ecology, and biogeography have not been previously analyzed. These topics are now addressed, with extensive use of SEM, in comparison with other North Atlantic arctic and subarctic melobesioid genera and species. The species considered in this article comprise 95% of the coralline biomass of the colder North Atlantic and adjacent arctic (i.e. less than 12° C summer and less than 0° C winter). In the outer thallus region of coralline algae, crust extension proceeds, calcification develops, surface sloughing and grazing occur, and reproductive structures are initiated. Analysis of the ultrastructure of the outer thallus region (epithallium, meristem, and perithallium) of L. tophiforme shows distinctive generic similarities and specific differences from the other Lithothamnion species discussed here. Considerable generic differences from the Clathromorpum and Leptophytum species also encountered in the region considered are highlighted as well. We discuss the functional and taxonomic implications of these distinguishing features and recommend that they be more widely considered in future research on coralline algae to understand more fully the ecology and evolution of the Corallinales.

Three species of Hydrolithon (Rhodophyta: Corallinaceae): Hydrolithon onkodes (Heydrich) Penrose and Woelkerling, Hydrolithon superficiale sp. nov., and H. samoense (Foslie) comb. nov. from South Africa

Three species of Hydrolithon are reported from South Africa. Hydrolithon onkodes occurs on the southernmost coral reefs in the western Indian Ocean at Sodwana Bay, Natal. Hydrolithon superficiale sp. nov. is described on the basis of a distinctive layer of conceptacles that occur in a superficial layer of lightly calcified filaments with long, thin cells, that are sharply differentiated from the filaments of short cells in the thallus below. This species has been found only in the Sodwana Bay area of Natal Province. Lithophyllum samoense Foslie is transferred to Hydrolithon on the basis of the anatomy of the tetrasporangial pore. It was also determined that H. samoense (Foslie) comb. nov. is conspecific with Spongites wildpretti Afonso-Carrillo and Neogoniolithon illitus (Lemoine) Afonso-Carrillo. Hydrolithon samoense is known to occur throughout South Africa.

Sporolithon ptychoides Heydrich and S. episporum (Howe) Dawson: two crustose coralline red algae (Corallinales, Sporolithaceae) in South Africa

The crustose coralline red alga, Sporolithon ptychoides Heydrich, is recorded from tide pools, subtidal surge channels, and on rock substrate on the southernmost coral reefs in the western Indian Ocean, at Sodwana Bay National Park, Natal Province, South Africa. Sporolithon episporum (Howe) Dawson is reported from large tide pools, surge channels, and shallow subtidal rocks subjected to sand scour and inundation in the same area, as well as from the south-western Cape Province. The material of S. episporum is compared with the type specimen, and the latter is described and illustrated. The two species are distinguished on the basis of cell connections and the burying of sporangia. Sporolithon ptychoides has both cell fusions and secondary pit connections, and sporangia buried in distinct rows. Sporolithon episporum has secondary pits but not cell fusions, and generally sheds old sporangia.

The non-geniculate coralline algae Synarthrophyton eckloniae (Foslie) comb. nov. and S. magellanicum (Foslie) comb. nov. (Rhodophyta) in South Africa including comparison with relevant types

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 A...

Lithothamnion superpositum Foslie: a common crustose red alga (Corallinaceae) in South Africa

Abstract A species of non-geniculate coralline alga that is common in the subtidal zone of South Africa (SA) was studied from collections made around the SA coast. It was compared with the holotype of Lithothamnion superpositum , to which it was found to conform. SA material and the type were also compared with published descriptions and illustrations of Lithothamnion indicum from Australia. These taxa are conspecific, so L. indicum is a heterotypic synonym of L. superpositum , which epithet has historical priority. Specimens from Madeira were also found to conform to this species.

The melobesioid alga Mesophyllum engelhartii (Rhodophyta, Corallinaceae) in South Africa

Mesophyllum engelhartii is a crustose coralline, melobesioid, red alga that is common in the Western Cape province and parts of the Eastern Cape province but becomes rare in KwaZulu-Natal. It occurs mainly on rocks and shells in the low intertidal and subtidal zones. The principal characters defining the species are the slightly to markedly prominent conceptacles and the structure of the tetra/bisporangial pore plate that is composed (in vertical section) of 4–6 somewhat elongate cells that are similar throughout and not specialized either in the conceptacle rim or in cells adjacent to pores. The following type specimens, described by Foslie on the basis of South African material, are shown to be conspecific with M. engelhartii : the lectotype and isolectotype of Lithothamnion discrepans , and the holotype of Lithothamnion synanablastum f. speciosa. The isotype of Goniolithon elatocarpum is probably also conspecific but bears only non-diagnostic carposporangial conceptacles. As the epithet engelhartii has nomenclatural priority, the other taxa are now subsumed in Mesolphyllum engelhartii which is a common southern Australian species.

The occurrence of Fosliella limitata (Foslie) Ganesan (a new British record) and F. lejolisii (Rosanoff) Howe (Rhodophyta, Corallinaceae) on the Isle of Wight

The occurrence of Fosliella limitata and F. lejolisii at Bembridge, Isle of Wight is reported. F. limitata is newly recorded for Britain whilst F. lejolisii has been found only rarely since disease struck Zostera in the early 1930s. The two epiphytes both grow on Zostera; F. limitata also grows on large brown and red algae. Their vegetative and reproductive structures are described and illustrated and information given regarding their seasonal occurrence from May 1975 to April 1976. Previous records of both species are discussed and a table is given summarizing the differences between the species.

Observations on Fosliella farinosa (Lamour.) Howe (Rhodophyta, Corallinaceae) in the British Isles

A description of Fosliella farinosa is given based on material collected in the British Isles between May 1975 and April 1977. Using field material and crusts cultured from uninucleate bispores the development and seasonal variation of the vegetative thallus and the trichocytes which it bears are discussed. The seasonal occurrence of the tetrasporangial, gametangial and bisporangial conceptacles is recorded. The previously little known bisporangial conceptacles are described in greater detail as is a sterile conceptacle form which develops in winter. Culture studies which have established the bisporangial life-history are reported. An account is given of the ecology of this species and finally the conflicting views of the delimitation of the genera Fosliella and Heteroderma are discussed.