A re‐assessment of the infra‐generic classification of the genusCaulerpa(Caulerpaceae,Chlorophyta) inferred from a time‐calibrated molecular phylogeny

Abstract

The siphonous green algal family Caulerpaceae includes the monotypic genus Caulerpella and the species-rich genus Caulerpa. A molecular phylogeny was inferred from chloroplast tufA and rbcL DNA sequences analyzed together with a five marker dataset of non-caulerpacean siphonous green algae. Six Caulerpaceae lineages were revealed, but relationships between them remained largely unresolved. A Caulerpella clade representing multiple cryptic species was nested within the genus Caulerpa. Therefore, that genus is subsumed and Caulerpa ambigua Okamura is reinstated. Caulerpa subgenus status is proposed for the six lineages substantiated by morphological characters, viz., three monotypic subgenera Cliftonii, Hedleyi, and Caulerpella, subgenus Araucarioideae exhibiting stolons covered with scale-like appendages, subgenus Charoideae characterized by a verticillate branching mode, and subgenus Caulerpa for a clade regarded as the Caulerpa core clade. The latter subgenus is subdivided in two sections, i.e., Sedoideae for species with pyrenoids and a species-rich section Caulerpa. A single section with the same name is proposed for each of the other five subgenera. In addition, species status is proposed for Caulerpa filicoides var. andamanensis (W.R. Taylor). All Caulerpa species without sequence data were examined (or data were taken from species descriptions) and classified in the new classification scheme. A temporal framework of Caulerpa diversification is provided by calibrating the phylogeny in geological time. The chronogram suggests that Caulerpa diversified into subgenera and sections after the Triassic-Jurassic mass extinction and that infra-section species radiation happened after the Cretaceous-Tertiary mass extinction.

Reassessment of the classification of Bryopsidales (Chlorophyta) based on chloroplast phylogenomic analyses

“…Vroom et al (1998) inferred the phylogeny of Bryopsidales using morphological and anatomical features. Subsequent studies utilized chloroplast-and nuclear-encoded gene sequences to further characterise the higher-level phylogeny of the order (Lam and Zechman, 2006;Verbruggen et al, 2009a), its families (Kooistra, 2002;Woolcott et al, 2000) and genera (De Clerck et al, 2008;Draisma et al, 2014;Famà et al, 2002;Hillis et al, 1998;Krellwitz et al, 2001;Verbruggen et al, 2009bVerbruggen et al, , 2007. A multi-locus molecular phylogeny of Bryopsidales recovered a well-supported, monophyletic Bryopsidineae (including families Bryopsidaceae, Codiaceae, and Derbesiaceae) and Halimedineae (including families Caulerpaceae, Dichotomosiphonaceae, Halimedaceae, Pseudocodiaceae, Rhipiliaceae, and Udoteaceae) (Verbruggen et al, 2009a).…”

Some New Records of Marine Algae From Vietnam

“…All specimens were cleaned and pressed into herbarium vouchers, or preserved in 5% formalin in seawater. The specimens were identified based on morphological and anatomical data, using published keys and taxonomic papers largely following Taylor (1965Taylor ( , 1975 [2,3], De Clerck et al, (2005) [4], Huisman et al, (2007) [5], Belton et al, (2014) [6] and Draisma et al, (2014) [7]. All specimens were deposited in the Herbarium of the Nha Trang Institute of Technology Research and Application (NITRA).…”

New records of marine algae in Vietnam

“…In a previous paper, Taylor (1965) [2] identified it as Caulerpa filicoides var. andamanensis but in a recent paper by Draisma et al (2014) [7] this taxon was considered to form a separate species, viz. Caulerpa andamanensis (W.R. Taylor) Draisma, Prud'homme & Sauvage.…”

“…Order Bryopsidales, Chlorophyta Caulerpa falcifolia Harvey & Bailey 1851: 373. References:Taylor (1975: 77);Draisma et al (2014Draisma et al ( : 1020.…”