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Monterey Bay Aquarium Research Institute
Marine Botany

Ceramium: Taxonomy

Phylum: Rhodophyta
Class: Florideophyceae
Subclass: Rhodymeniophycidae
Order: Ceramiales
Family: Ceramiaceae
Genus: Ceramium

Local species in the Monterey Bay area include:
C. californicum, C. codicola, C. gardneri, C. kondoi, and C. pacificum.

Globally, there are up to 191 species of Ceramium in existence. Some of the species are highly localized, existing in only a small area (such as C. hanaense in the Hawaiian Islands) while others are widespread (such as C. flaccidum). In addition, the species is common at multiple tide heights, ranging from middle intertidal to subtidal down to 30 m depth.

How is this species so cosmopolitan? Some possible reasons I came up with for this are:

it can easily and quickly take up of nutrients
its structure is not complex to produce
it has an isomorphic life history where both phases can live in the same environment
it has some amount of herbivory defense via free sulfur in its cells
its corticated structure is particularly tolerant of harsh environments, in terms of salinity, nutrients, temperatures

Whether these reasons are the real factors causing Ceramium’s global range or not, it is interesting to try to determine why this alga is so successful evolutionarily.

Click on the boxes in the map to find out which species of Ceramium live in that region.

India Western South Africa Tropical West Africa British Isles Southeast Coast of the United States Caribbean Chile Northwest Coast of North America Hawaii French Polynesia China Philippines Great Barrier Reef Southern Australia  

Changes in classification:

Maggs et al. (2002) suggest that certain morphological characters are less valid than previously thought in determining species relationships. For example, they cite work in Garbary et al. (1978), Suh and Lee (1984), and Cormaci and Motta (1984) that shows that laboratory culture conditions affect the amount of cortication and curvature of branch apices in Ceramium. Different specimens from the same species showed differing amounts of cortication and different curvature of branches.

In 2000, T.O. Cho et al. point out specific characters that distinguish three closely related genuses in the Ceramiales: Ceramium, Corallophila, and Centroceras. By looking at specific patterns of cortex cell shape and orientation and development and location of reproductive structures, they determined that the structure and reproduction of the species Ceramium eatonianum is distinct enough from other Ceramium species to be placed in the genus Corallophila. Corallophila eatoniana (as it is now called) has fairly rectangular cortical cells arranged in very even lines, as well as having no involucral branches supporting the cystocarp, unlike Ceramium species. Previous to being in the genus Ceramium, this same species was in the genus Centroceras, from which it was removed in 1903.

Last updated: Feb. 05, 2009