RAPD differentiation of Grateloupia lanceola and the invasive Grateloupia turuturu (Gigartinales, Rhodophyta) in the Iberian Peninsula

Grateloupia is a genus of red algae in which many species are notoriously difficult to define; this situation greatly complicates the assessment of their geographical ranges. A member of this genus, G. lonceola, is typical of warm-temperate seas but retains some highly localized populations at higher latitudes on the northwestern Iberian Peninsula (Galicia). Nevertheless, the presence of these northern populations has been largely overlooked; instead, they have been regarded as, or Suspected to be, another case in the expansion of the adventive congeneric Grateloupia turuturu along European waters. In this study, we have examined the genetic similarity between specimens of G. lanceola and G. turuturu from Galicia using randomly amplified polymorphic DNA (RAPD) markers. The large genetic distance between species detected provides molecular-based Support for the Occurrence of G. lonceola in the northwestern Iberian Peninsula as a separate species from the invasive G. turuturu, corroborating earlier morphological and ecological observations. Also, G. lanceola specimens from Galicia were genetically similar to those from their type locality in the southern Iberian Peninsula, confirming their conspecific character. Our results imply that their the first records of invasive G. turuturu in northwestern waters of Spain were those from the early 1990s contrary to most references in the literature, previous older records from the early 1980s belonged to the congeneric G. lanceola.