The bladed Bangiales (Rhodophyta) of the South Eastern Pacific: Molecular species delimitation reveals extensive diversity.

ABSTRACT

A molecular taxonomic study of the bladed Bangiales of the South Eastern Pacific (coast of Chile) was undertaken based on sequence data of the mitochondrial COI and chloroplast rbcL for 193 specimens collected from Arica (18°S) in the north to South Patagonia (53°S) in the south. The results revealed for the first time that four genera, Porphyra, Pyropia, Fuscifolium and Wildemania were present in the region. Species delimitation was determined based on a combination of a General Mixed Yule Coalescence model (GMYC) and Automatic Barcode Gap Discovery (ABGD) coupled with detection of monophyly in tree reconstruction. The overall incongruence between the species delimitation methods within each gene was 29%. The GMYC method led to over-splitting groups, whereas the ABGD method had a tendency to lump groups. Taking a conservative approach to the number of putative species, at least 18 were recognized and, with the exception of the recently described Pyropia orbicularis, all were new to the Chilean flora. Porphyra and Pyropia were the most diverse genera with eight 'species' each, whereas only a 'single' species each was found for Fuscifolium and Wildemania. There was also evidence of recently diverging groups Wildemania sp. was distinct but very closely related to W. amplissima from the Northern Hemisphere and raises questions in relation to such disjunct distributions. Pyropia orbicularis was very closely related to two other species, making species delimitation very difficult but provides evidence of an incipient speciation. The difference between the 'species' discovered and those previously reported for the region is discussed in relation to the difficulty of distinguishing species based on morphological identification.