Unmasking a cryptic ethnotaxon: a case study on the identity of Dermonema virens (Nemaliales, Rhodophyta) in the Philippines

Abstract

Indigenous knowledge on seaweed utilisation in the Philippines is common; with the coastal natives of the country’s northern region regarded as the most knowledgeable. Dependence on use of vernacular seaweed names valorises traditional wisdom, however, this is prone to taxonomic ambiguities. Such is the case for cryptic seaweed ethnotaxa whose accurate taxonomic recognition largely falls short. Known in the northern Philippines as an edible seaweed, the taxonomy of Salingongo or Kaññungu remains ambiguous. Molecular analysis based on plastid rbcL gene sequences revealed the identity of Salingongo/Kaññungu as Dermonema virens. Due to lack of any available mitochondrial DNA sequences for D. virens in GenBank, the COI-5P and cox2-3 spacer sequences generated from this study did not permit species recognition. The newly sequenced mtDNA accessions therefore served, otherwise, as the database representing the first mtDNA sequence reference for D. virens. The use of D. virens as an edible seaweed in the Philippines further reinforces the extensive overlap of traditional knowledge with regard to seaweed utilisation between the indigenous people from Taiwan and the northern Philippines. The case study presented here underpins the utility of molecular analysis, along with morphological evaluation, as a key combinatory tool for unmasking the diversity of seaweed ethnotaxa.