Ligulate Desmarestia (Desmarestiales, Phaeophyceae) revisited: D. japonica sp. nov. and D. dudresnayi differ from D. ligulata

Abstract

The phylogeny of ligulate and sulfuric‐acid containing species of Desmarestia, occurring worldwide from polar to temperate regions, was revised using a multigenic and polyphasic approach. Sequence data, gametophyte characteristics, and sporophyte morphology support reducing a total of 16 taxa to four different species. (1) D. herbacea, containing broad‐bladed and highly branched forms, has dioecious gametophytes. The three other species have monoecious gametophytes: (2) D. ligulata which is profusely branched and, except for one subspecies, narrow‐bladed, (3) Japanese ligulate Desmarestia, here described as D. japonica sp. nov., which is morphologically similar to D. ligulata but genetically distant from all other ligulate taxa. This species may have conserved the morphology of original ligulate Desmarestia. (4) D. dudresnayi, including unbranched or little branched broad‐bladed taxa. A figure of the holotype of D. dudresnayi, which was lost for decades, was relocated. The taxonomy is complemented by a comparison of internal transcribed spacer and cytochrome c oxidase subunit I (cox1) as potential barcode loci, with cox1 offering good resolution, reflecting species delimitations within the genus Desmarestia.

Molecular evidence for the coexistence of two sibling species in Pylaiella littoralis (Ectocarpales, Phaeophyceae) along the Brittany coast

“…Thus, our results are in agreement with the recent proposals on Desmaretiales (Yang et al. ) and Ectocarpales (Peters et al. in press) that estimated species‐level cut‐off at divergence of ~1.2% and 1.8%, respectively.…”

Arctic marine phytobenthos of northern Baffin Island

“…F), acid‐producing Desmarestia species (Yang et al. ) were much smaller both in terms of thallus size and biomass contribution to this community. Sporophytes of D. viridis were collected at Cape Hatt in 1981 and 2004, but not during the 2009 expedition.…”

“…to ) however, the genetic distance of 5% to the latter in 5′‐COI lies beyond the species‐limit cut‐off at 1.3% (Yang et al. ) and suggests that they belong to a different, closely related species. Such a putative sister species of D. viridis is so far unknown and has not been seen in previous molecular studies; isolates of D. viridis from Europe, Japan, and southernmost South America (under the name D. willii ) differed by just a single nucleotide substitution in ITS (van Oppen et al.…”

Delimitation of cryptic species of the Scytosiphon lomentaria complex (Scytosiphonaceae, Phaeophyceae) in Japan, based on mitochondrial and nuclear molecular markers

“…Gaps between intraspecific and interspecific pairwise distances have been reported for some molecular markers including cox1 even in closely related seaweed species although such gaps are not necessarily found (Sites & Marshall 2004;Mattio & Payri 2010;Yang et al 2014). In the scatter plot analyses, distributions of pairwise genetic distances showed gaps (lines 6-8 in Fig.…”