Chrysoreinhardia giraudii (Derbe`s et Solier) Billard
(Figs 3 6)
Basionym:
Suppl. C. R. Acad. Sci., I: 8, pl. I, figs. 1 6, 1856.
Synonyms: Phaeocystis giraudii (Derbe`s et Solier) Lagerheim, Pulvinaria giraudii (Derbe` s et Solier) Bourrelly (invalid combination: incomplete refer- ence).
Description: The mucilaginous light brownish colonies are up to 15 mm in diameter (Fig. 6). Cells are hemispherical to spherical, 7 10 mm in diameter and are embedded in a homogeneous non-stratified mucilage (palmelloid stage) or in a stratified mucilage (gloeocystoid stage) (Fig. 5). Numerous granules are present at the periphery of the cell. Cells contain two yellow-brown chloroplasts with pyrenoids and one or several lipidic granules. Reproduction is by vegetative cell division and by zoospore formation.
Habitat and ecology: Chrysoreinhardia giraudii was first collected at Alga (not Algajola as erroneously reported) in Revellata Bay in June 1979 from the rhi- zomes of Posidonia oceanica (L.) Delile, at a depth of 3 m by one of the authors (VD)(Coppejans and Boudouresque 1983), but was inconspicuous until 1989. The development of C. giraudii is maximal at the end of spring and in summer (Table I). It generally appears in macroscopically visible aggregates in May and disappears in September. In 1997 and 1998, the colonies remained in large numbers until November. From our collection data, C. giraudii extends to a depth of at least 38 meters, but is often more sparse below 20 m. The maximum development is usually at shallow depths in relatively calm and well lit situations in agreement with Verlaque’s (1987) classification in the ‘groupe photophile infralittoral thermophile’. There it can form a layer several mm thick (Figs 3, 4) that replaces the macroalgae. In more exposed situations it may, however, start deeper and have its maximum at depths of 15 20 m. Competition with Nematochrysopsis marina, which is even more wave limited, seems to be a major factor in usually limiting this latter species to the first 10 meters. Dry weight: up to 400 mg cm 2; organic matter: up to 110 mg cm 2, chlorophyll a: up to 0.25 mg cm 2.
Geographic distribution: Corsica [Bay of Revellata (Coppejans and Boudouresque 1983, this study), Pte Caldano, Punta Bianca, Bravone, Gulf of Porto, Porto-Vecchio (this study), Galeria (Verlaque 1987)]; Mediterranean coast of France (Castagne 1851, Derbe`s and Solier 1856, Hamel 1930); Adriatic Sea (Feldmann in Magne 1959); Red Sea (Nasr 1941).
Comments: This benthic species, first described in the genus Tetraspora, and later transferred to the genus Phaeocystis Lagerheim (Haptophyceae), belongs in fact to the genus Pulvinaria Reinhard ( Chrysoreinhardia Billard) as suggested by Bourrelly (1957). Bourrelly’s combination (1957: 373) was, however, invalid according to article 33 of the International Code of Botanical Nomenclature (Greuter et al. 1994), as no complete reference to the basionym was given.
The type species of Chrysoreinhardia, C. algicola, also forms mucilaginous colonies (1 2 mm in dia- meter) epiphytic on macroalgae such as species of Ceramium and Striaria and is closely related to C. giraudii, if not conspecific. Chrysoreinhardia algicola is known so far from a single collection from the shores of the Black Sea (Reinhard 1885). If C. gi- raudii and C. algicola proved to be identical, the specific epithet ‘giraudii’ would nevertheless have priority over ‘algicola’.
The third species of the genus is C. feldmannii (Bourrelly et Magne) Billard et Fresnel comb. nov. (basionym: Chrysobotrys feldmannii Bourrelly et Magne, Rev. ge ́n. Bot. 60: 684, 1953). Synonym: Pulvinaria feldmannii (Bourrelly et Magne) Billard et Fresnel (Cryptogamie: Algologie 1: 281, 1980). It forms almost monospecific stands on the mud at the base of halophytes or on porous limestone rocks in the supralittoral zone of the French Atlantic coast (Billard and Fresnel 1980, Billard 1988).
(Also some of the comments I think I had quoted earlier (elsewhere) apply to different species altogether, so leaving those out.)
