A re‐assessment of the infra‐generic classification of the genus Caulerpa (Caulerpaceae, Chlorophyta) inferred from a time‐calibrated molecular phylogeny. Issue 6 (9th October 2014)

• Record Type: Journal Article
• Authors: Draisma, Stefano G.A.; van Reine, Willem F. Prud'homme; Sauvage, Thomas; Belton, Gareth S.; Gurgel, C. Frederico D.; Lim, Phaik‐Eem; Phang, Siew‐Moi; Verbruggen, H.
• Is Part Of: Journal of phycology. Volume 50:Issue 6(2014:Dec.)
• Page Start: 1020
• Page End: 1034
• Publication Date: 2014-10-09
• Subjects: Algae -- Periodicals; 579.8
• DOI: 10.1111/jpy.12231
• Languages: English
• ISSNs: 0022-3646

Abstract

<abstract abstract-type="main" id="jpy12231-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The siphonous green algal family Caulerpaceae includes the monotypic genus <italic>Caulerpella</italic> and the species‐rich genus <italic>Caulerpa</italic>. A molecular phylogeny was inferred from chloroplast <italic>tuf</italic>A and <italic>rbc</italic>L 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 <italic>Caulerpella</italic> clade representing multiple cryptic species was nested within the genus <italic>Caulerpa</italic>. Therefore, that genus is subsumed and <italic>Caulerpa ambigua</italic> Okamura is reinstated. <italic>Caulerpa</italic> subgenus status is proposed for the six lineages substantiated by morphological characters, viz., three monotypic subgenera <italic>Cliftonii, Hedleyi</italic>, and <italic>Caulerpella</italic>, subgenus <italic>Araucarioideae</italic> exhibiting stolons covered with scale‐like appendages, subgenus <italic>Charoideae</italic> characterized by a verticillate branching mode, and subgenus <italic>Caulerpa</italic> for a clade regarded as the <italic>Caulerpa</italic> core clade. The latter subgenus is subdivided in two sections, i.e., <italic>Sedoideae</italic> for species with pyrenoids and a species‐rich section <italic>Caulerpa</italic>. A single section with the same name is proposed for each of the other five subgenera. In addition, species status is proposed for <italic>Caulerpa filicoides</italic> var. <italic>andamanensis</italic> (W.R. Taylor). All <italic>Caulerpa</italic> species without sequence data were examined (or data were taken from species descriptions) and classified in the new classification scheme. A temporal framework of <italic>Caulerpa</italic> diversification is provided by calibrating the phylogeny in geological time. The chronogram suggests that <italic>Caulerpa</italic> diversified into subgenera and sections after the Triassic‐Jurassic mass extinction and that infra‐section species radiation happened after the Cretaceous‐Tertiary mass extinction.</p> </abstract>