PHYLOGENETIC ANALYSIS OF THE LARGE SUBUNIT RUBISCO GENE SUPPORTS THE EXCLUSION OF AVRAINVILLEA AND CLADOCEPHALUS FROM THE UDOTEACEAE (BRYOPSIDALES, CHLOROPHYTA)(1).

The placement of Avrainvillea and Cladocephalus in the family Udoteaceae (order Bryopsidales) has been questioned on the basis of nuclear, plastid, and other ultrastructural characteristics unique to these genera. Bayesian analysis of the chloroplast-encoded LSU RUBISCO (rbcL) gene showed that the Udoteaceae is paraphyletic. Cladocephalus luteofuscus (P. Crouan et H. Crouan) Børgesen, Avrainvillea nigricans f. floridana D. Littler et Littler, and A. mazei G. Murray et Boodle form a clade with the freshwater alga Dichotomosiphon tuberosus (A. Braun ex Kütz.) A. Ernst that is basal to a clade that includes other members of the Udoteaceae, the Halimedaceae, and the Caulerpaceae. The noncalcified species Boodleopsis pusilla (Collins) W. R. Taylor, A. B. Joly et Bernat. groups with species of the calcified Udoteacean genera Penicillus, Rhipocephalus, Udotea, and Halimeda.