|Characterization and phylogenetic position of the red alga Besa papillaeformis Setchell: an example of progenetic heterochrony?|
Fredericq, S.; Lopez-Bautista, J.M. (2002). Characterization and phylogenetic position of the red alga Besa papillaeformis Setchell: an example of progenetic heterochrony? Constancea 83: [no pag.]
In: Constancea: University of California Electronic Publications in Botany. University of California: Berkeley, more
|Authors|| || Top |
- Fredericq, S.
- Lopez-Bautista, J.M.
In order to elucidate the taxonomic placement of the enigmatic red alga Besa papillaeformis Setchell, fragments from topotype material collected by W.A. Setchell in 1912 were sectioned for morphological observation, and processed for chloroplast-encoded rbcL sequencing. The morphological and molecular analyses confirm that Besa is a member of the Phyllophoraceae, Gigartinales, in the Ahnfeltiopsis paradoxa/Mastocarpus clade. The multiple diminutive axes of B. papillaeformis, each up to 0.4 mm tall borne on a fleshy-cartilaginous epilithic crust, typically resemble the erect juvenile stages of the Phyllophoraceae, as well as the reproductive papillae of Mastocarpus. Heterochrony, in particular progenesis — the process by which sexual maturity is accelerated relative to somatic development — is inferred as the mechanism for the evolutionary origin of Besa, in which perennating crusts give rise to uprights that become reproductive while remaining miniaturized. The isomorphic Besa-type life cycle encompasses proterandrous monoecy (and possibly self-fertilization), and is one more example of the wide range of life history types characteristic of the Phyllophoraceae.