Genetic discontinuity of Digenea (Rhodomelaceae, Rhodophyta) from Mexico supports recognition of two new species, D. mexicana and D. rafaelii

  • Boo, Ga Hun (University Herbarium, University of California Berkeley) ;
  • Robledo, Daniel (Department of Marine Resources, Centro de Investigacion y Estudios Avanzados Unidad Merida) ;
  • Andrade-Sorcia, Gabriella (Programa de Investigacion en Botanica Marina, Departamento de Biologia Marina, Universidad Autonoma de Baja California Sur) ;
  • Boo, Sung Min (Department of Biology, Chungnam National University)
  • Received : 2018.07.08
  • Accepted : 2018.08.20
  • Published : 2018.09.15


Genetic continuity of Digenea simplex outside the Atlantic waters remains less studied, despite its long exposure to oriental folk medicine and wide distribution in tropical waters. Mitochondrial COI-5P and plastid rbcL sequences and morphology were investigated for plants from Mexico and additional specimens from Japan. Two new species, Digenea mexicana and Digenea rafaelii, are described for plants that would previously have been recognized as D. simplex in Mexico. D. mexicana grows to 10.5 cm tall and has cylindrical axes, irregular or di-, trichotomous branches, simple to branched determinate branchlets with eight pericentral cells, and tetrasporangia on inflated upper parts of determinate branchlets. It occurs intertidally in Quintana Roo, Yucatan Peninsula. D. rafaelii grows to 5 cm tall and has cylindrical axes, irregular or di-, trichotomous branches, and simple determinate branchlets with ten pericentral cells. It occurs intertidally in the Gulf of California. Both COI-5P and rbcL sequences revealed the genetic discontinuity between D. mexicana and D. rafaelii.


  1. Agardh, C. A. 1822. Species algarum rite cognitae, cum synonymis, differentiis specificis et descriptionibus succinctis, Volumen primum pars posterior. Ex officina Berlingiana, Lundae, pp. 169-398.
  2. Benson, D. A., Cavanaugh, M., Clark, K., Karsch-Mizrachi, I., Ostell, J., Pruitt, K. D. & Sayers, E. W. 2018. GenBank. Nucleic Acids Res. 46:D41-D47.
  3. Boo, G. H., Hughey, J. R., Miller, K. A. & Boo, S. M. 2016a. Mitogenomes from type specimens, a genotyping tool for morphologically simple species: ten genomes of agarproducing red algae. Sci. Rep. 6:e35337.
  4. Boo, G. H., Le Gall, L., Miller, K. A., Freshwater, D. W., Wernberg, T., Terada, R., Yoon, K. J. & Boo, S. M. 2016b. A novel phylogeny of the Gelidiales (Rhodophyta) based on five genes including the nuclear CesA, with descriptions of Orthogonacladia gen. nov. and Orthogonacladiaceae fam. nov. Mol. Phylogenet. Evol. 101:359-372.
  5. Boo, G. H., Park, J. K. & Boo, S. M. 2013. Gelidiophycus (Rhodophyta: Gelidiales): a new genus of marine algae from East Asia. Taxon 62:1105-1116.
  6. Cabioc'h, J., Floc'h, J. -Y., Le Toquin, A., Boudouresque, C. -F., Meinesz, A. & Verlaque, M. 2006. Guide des algues des mers d'Europe. Delachaux et Niestle, Paris, 272 pp.
  7. Dawson, E. Y. 1957. Marine algae from the Pacific Costa Rican Gulfs. Los Angeles County Mus. Contrib. Sci. 15:1-28.
  8. Dawson, E. Y. 1963. Marine red algae of Pacific Mexico. Part 8. Ceramiales: Dasyaceae, Rhodomelaceae. Nova Hedwigia 6:401-481.
  9. De Clerck, O., Bolton, J. J., Anderson, R. J. & Coppejans, E. 2005. Guide to the seaweeds of KwaZulu-Natal. National Botanic Garden of Belgium, Meise, 294 pp.
  10. De Toni, J. B. 1903. Sylloge Algarum omnium hucusque cognitarum, Vol. 4. Florideae, Section III. Sumptibus auctoris, Padua, pp. 777-1521.
  11. Diaz-Tapia, P., Maggs, C. A., West, J. A. & Verbruggen, H. 2017. Analysis of chloroplast genomes and a supermatrix inform reclassification of the Rhodomelaceae (Rhodophyta). J. Phycol. 53:920-937.
  12. Dreckmann, K. M. & Senties, G. A. 1994. El alga Digenea simplex (Ceramiales: Rhodomelaceae) en Mexico: variación biogeografica. Rev. Biol. Trop. 42:443-453.
  13. Ebadi, M. 2006. Pharmacodynamic basis of herbal medicine. 2nd ed. CRC Press, London, 699 pp.
  14. Freshwater, D. W. & Rueness, J. 1994. Phylogenetic relationships of some European Gelidium (Gelidiales, Rhodophyta) species based on rbcL nucleotide sequence analysis. Phycologia 33:187-194.
  15. Guiry, M. D. & Guiry, G. M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Available from: Accessed May 4, 2018.
  16. Huisman, J. M. & Borowitzka, M. A. 2003. Marine benthic flora of the Dampier Archipelago, Western Australia. In Wells, F. E., Walker, D. I. & Jones, D. E. (Eds.) The Marine Flora and Fauna of Dampier, Western Australia. Western Australian Museum, Perth, pp. 291-344.
  17. Kang, J. C. & Kim, M. S. 2013. A novel species Symphyocladia glabra sp. nov. (Rhodomelaceae, Rhodophyta) from Korea based on morphological and molecular analyses. Algae 28:149-160.
  18. Kutzing, F. T. 1865. Tabulae Phycologicae: oder, Abbildungen der Tange. Vol. 15. Gedrucht auf kosten des Verfassers, Nordhausen, 33 pp.
  19. Kylin, H. 1956. Die Gattungen der Rhodophyceen. C.W.K. Gleerups Forlag, Lund, 673 pp.
  20. Lewis, S. M., Norris, J. N. & Searles, R. B. 1987. The regulation of morphological plasticity in tropical reef algae by herbivory. Ecology 68:636-641.
  21. Mendoza-Gonzalez, A. C. & Mateo-Cid, L. E. 1986. Flora marina bentónica de la coasta noroeste del estado de Sonora, Mexico. Phytologia 60:414-427.
  22. Millar, A. J. K. & Prud'homme van Reine, W. F. 2005. Marine benthic macroalgae collected by Vieillard from New Caledonia and described as new species by Kutzing. Phycologia 44:536-549.[536:MBMCBV]2.0.CO;2
  23. Norris, J. N. 2010. Marine algae of the Northern Gulf of California: Chlorophyta and Phaeophyceae. Smithson. Contrib. Bot. 94:1-276.
  24. Norris, J. N. 2014. Marine algae of the Northern Gulf of California II: Rhodophyta. Smithson. Contrib. Bot. 96:1-555.
  25. Norris, R. E. 1994. Some cumophytic Rhodomelaceae (Rhodophyta) occurring in Hawaiian surf. Phycologia 33:434-443.
  26. Orfanidis, S. & Breeman, A. M. 1999. Geographic variation in thermal traits in Digenea simplex and Champia parvula (Rhodophyta) in relation to present and glacial temperate regimes. J. Phycol. 35:919-930.
  27. Pakker, H., Klerck, H., van Campen, J. H., Olsen, J. L. & Breeman, A. M. 1996. Evolutionary and ecological differentiation in the pantropical to warm-temperate seaweed Digenea simplex (Rhodophyta). J. Phycol. 32:250-257.
  28. Pereira, J. G., Mesquita, J. X., Aragão, K. S., Franco, A. X., Souza, M. H. L. P., Brito, T. V., Dias, J. M., Silva, R. O., Medeiros, J. -V. R., Oliveira, J. S., Abreu, C. M. W. S., de Paula, R. C. M., Barbosa, A. L. R. & Freitas, A. L. P. 2014. Polysaccharides isolated from Digenea simplex inhibit inflammatory and nociceptive responses. Carbohydr. Polym. 108:17-25.
  29. Ronquist, F., Teslenko, M., van der Mark, P., Ayres, D. L., Darling, A., Höhna, S., Larget, B., Liu, L., Suchard, M. A. & Huelsenbeck, J. P. 2012. MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. Syst. Biol. 61:539-542.
  30. Saunders, G. W. & Moore, T. E. 2013. Refinements for the application and sequencing of red algal DNA barcode and RedToL phylogenetic markers: a summary of current primers, profiles and strategies. Algae 28:31-43.
  31. Schneider, C. W., Hamzeh, B. F., Lane, C. E. & Saunders, G. W. 2018. A new species of Digenea (Rhodomelaceae, Ceramiales) based upon a molecular assessment and morphological observations of plants historically known as D. simplex in Bermuda. Phytotaxa 338:90-98.
  32. Silva, P. C., Basson, P. W. & Moe, R. L. 1996. Catalogue of the benthic marine algae of the Indian Ocean. Univ. Calif. Publ. Bot. 79:1-1259.
  33. Simons, R. H. 1970. Marine algae from southern Africa. 1. Six new species from the inter- and infra-tidal zones. Invest. Rep. Div. Sea Fish. S. Afr. 88:1-13.
  34. Stamatakis, A. 2014. RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics 30:1312-1313.
  35. Takano, R., Shiomoto, K., Kamei, K., Hara, S. & Hirase, S. 2003. Occurrence of carrageenan structure in an agar from the red seaweed Digenea simplex (Wulfen) C. Agardh (Rhodomelaceae, Ceramiales) with a short review of carrageenan-agarocolloid hybrid in the Florideophycidae. Bot. Mar. 46:142-150.
  36. Taylor, W. R. 1945. Pacific marine algae of the Allan Hancock Expedition to the Galapagos Islands. Allan Hancock Pac. Exped. 12:1-528.
  37. Thiers, B. 2018. Continuously updated. Index Herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden's Virtual Herbarium. Available from: Accessed Jun 10, 2018.
  38. Trono, G. C. Jr. 1997. Field guide and atlas of the seaweed resources of the Philippines. Bookmark Inc., Makati, 303pp.
  39. Tseng, C. K. 1983. Common seaweeds of China. Science Press, Beijing, 316 pp.
  40. Yoshida, T. 1998. Marine algae of Japan. Uchida Rokakuho, Tokyo, 1222 pp.