Molecular assessment of Ulvophyceae reveals cryptic diversity and new records of macroalgal species in Senegal

2025

Article référencé dans le Web of Science WOS:001613285700001

Diop M. S., Weinberger F., Kunzel S., Ndiaye W. N., Mbaye M. S., Diedhiou F., Fricke A., Quack B., Bousso N. C., Bolchi G., Fall S., Noba K., Brehmer Patrice

European Journal of Phycology, 2025, [Early access], p. [15 p.] ISSN 0967-0262

Some Ulvophyceae are cryptic due to their morphological plasticity and lack of distinct traits. Consequently, molecular approaches such as DNA barcoding and metabarcoding are essential for accurate species discrimination. Large parts of the African coastline remain understudied in this respect. In this study, Ulvophyceae were collected from various substrates at 24 coastal sites along the Senegalese coast. DNA barcoding targeting the tufA gene and metabarcoding targeting the rbcL gene were applied to these samples. Most of the sequences obtained represented four species (Ulva lactuca, U. compressa, Codium decorticatum and C. isthmocladum) already reported in Senegalese species inventories. However, the molecular assessment also confirmed the presence of U. ohnoi (described from Japan), U. tepida (distributed in the Indo-Pacific), U. chaugulei (previously reported from India, Iran, Israel, China and Brazil), Chaetomorpha valida (described from Tasmania, Australia), and a specimen similar in rbcL sequence to several Ulva species originating from New Caledonia, French Polynesia, India and China, i.e. South Pacific, Indian Ocean and South China Sea. Additionally, the Mediterranean species Bryopsis muscosa has reached Senegal. Morphological identification also suggested the presence of Caulerpa chemnitzia var. turbinata and Caulerpa chemnitzia var. laetevirens in West Africa. The challenges of morphological identification, particularly for Ulvophyceae, are evident, emphasizing the necessity of molecular data for accurate species discrimination. The detection of previously unrecorded species raises questions about whether their presence in Senegal results from global change, such as climate shifts and increased maritime transport, or the limitations of past morphological inventories. Further investigations should focus on clarifying the taxonomy of key genera (Cladophora, Caulerpa, Bryopsis, Codium and Chaetomorpha) through broader sampling and the application of advanced molecular markers to better understand Senegal's Ulvophyceae biodiversity and facilitate monitoring future changes in species composition due to environmental shifts or anthropogenic pressures.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Limnologie biologique / Océanographie biologique [034]

SENEGAL

Fonds IRD [F B010095536]

fdi:010095536