Rosenvingea orientalis (Scytosiphonaceae, Phaeophyceae) from Chiapas, Mexico: life history in culture and molecular phylogeny

doi:2010.25.4.187

Algae > Volume 25(4); 2010 > Article

Algae 2010;25(4): 187-195. doi: https://doi.org/10.4490/algae.2010.25.4.187

John A. West¹^,*, Giuseppe C. Zuccarello², Francisco F. Pedroche³ and Susan Loiseaux de Goër⁴

¹School of Botany, University of Melbourne, Parkville VIC 3010, Australia
²School of Biological Sciences, Victoria University of Wellington, Wellington 6140, New Zealand
³Departamento de Hidrobiología, Universidad Autónoma Metropolitana-Iztalapa. A.P. 55-535, México, D.F. 09340, Mexico
⁴11 Rue des Moguerou, 29680 Roscoff, France

*Corresponding Author

Email: jwest@unimelb.edu.au

ABSTRACT

The genus Rosenvingea is well known in the tropics. Four species have been reported from Pacific Mexico: R. floridana, R. antillarum, R. intricata and R. sanctae-crucis. We collected a plant (Boca del Cielo, Chiapas) that we identified as Rosenvingea orientalis, a species not previously reported from Pacific Mexico. We were able to characterize the life cycle of this species for the first time in laboratory culture. It reproduced exclusively by plurilocular sporangia (plurangia). The mature plants were up to 6 cm long with cylindrical to compressed fronds (to 2 mm wide) with dichotomous branches in the upper half of the thallus. The medulla was hollow with 2-3 layers of large inflated colourless cells at the periphery. The cortex was comprised of 1 layer of small cells, each with a single chloroplast and pyrenoid. Linear plurangial sori with phaeophycean hairs formed along the mature fronds. Zoospore germlings developed into prostrate filamentous systems, each with a single phaeophycean hair that gave rise to a single erect shoot with multiple hairs arising near the tip. Molecular phylogeny using the psaA gene placed this isolate within the Scytosiphonaceae. It does not confirm the exact identification of R. orientalis, although its placement close to other Rosenvingea sequences was confirmed and morphological evidence supports its placement in R. orientalis. Our culture investigations indicated that it has an asexual life cycle. Further collections are needed to resolve the full generic and specific relationships of Rosenvingea and related taxa, and their reproductive patterns.

Key words: asexual life cycle; molecular phylogeny; Pacific Mexico; Phaeophyceae; plurangia; psaA; Rosenvingea