Draisma S. G. A. auteur aut IRD Sauvage T. auteur aut IRD Lagourgue L. auteur aut IRD Kato A. auteur aut IRD Dumilag R. V. auteur aut IRD Lim P. E. auteur aut IRD Zubia M. auteur aut IRD Payri Claude auteur aut IRD text journalArticle eng text/pdf born digital access The green algal genus Caulerpa is known for high levels of morphological plasticity and cryptic diversity, rendering morphology-based identifications unreliable. The present study assessed the Caulerpa species diversity in the Central Indo-Pacific realm (CIP) using tufA DNA barcodes. A phylogenetic tree was constructed from 700 tufA sequences from the CIP supplemented with sequences from a reference sequence library. Most species were monophyletic, but in a few cases species delimitation was contentious. The subgenera Araucarioideae, Caulerpella, and Charoideae were represented by, respectively, one, four, and four species in the CIP, including cryptic species. The subgenus Caulerpa section Sedoideae was represented by at least nine species, including a dark taxon (a genetically distinct specimen that cannot be linked to a formally described species) resembling C. microphysa. Other specimens, originally identified as C. microphysa, were all assigned to two C. lentillifera subclades that may represent two cryptic species. Subgenus Caulerpa section Caulerpa was represented by at least 27 species, including two dark taxa. Caulerpa macra and C. macrodisca could each represent two distinct species, whereas C. manorensis could not be distinguished from one of the C. macra subclades based on tufA. The tufA barcode is a powerful tool to assist in Caulerpa species identification. However, for some taxa an additional marker is recommended for reliable identification. Based on tufA, we arrived at a conservative count of 45 Caulerpa species within the CIP. New Caulerpa records were reported for several countries. specialized Cryptic species DNA barcoding Morphological plasticity Species complex Species delimitation OCEAN INDIEN PACIFIQUE 034 [Early access] [22 p.] 2025 0031-8884 https://www.documentation.ird.fr/hor/fdi:010095505 10.1080/00318884.2025.2575521 0031-8884 [F B010095505] https://www.documentation.ird.fr/hor/fdi:010095505 https://www.documentation.ird.fr/intranet/publi/2025-12/010095505.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-12-10 2025-12-10 fdi:010095505 fre