Search

The taxonomic status of species assigned to the marine red algal genus Osmundea from Pacific North America has not been critically studied. We analyzed the complete organellar genomes of an isotype specimen of O. sinicola and conducted a genetic comparison of rbcL and COI-5P markers based on 15 specimens of Laurencia scrippsensis, O. crispa, and O. sinicola collected from California, the Gulf of California, and Pacific Baja California, including their type specimens. The mitogenome of O. sinicola was 25,021 bp in length and contained 44 genes, and the plastid genome was 171,419 bp with 225 genes. Both genomes show a high level of gene synteny with previously published organellar chromosomes from the Rhodomelaceae. Phylogenetic analysis of the rbcL and COI-5P genes identified two distinct clades, one containing the isotype of O. sinicola, and the other included the isotype of O. crispa and holotype of Laurencia scrippsensis. These data show that L. scrippsensis is a heterotypic synonym of O. crispa, rather than of O. sinicola. They support the recognition of two species, O. crispa from Monterey, California to Baja California Sur, and O. sinicola from Baja California Sur to the Gulf of California. California specimens identified as O. sinicola are misidentified O. crispa. Reports of O. sinicola from outside this range based on morpho-anatomy require confirmation by DNA sequencing. These genetic results highlight the need further analyses of type material from the Rhodomelaceae.

Gigartina skottsbergii is the currently accepted name for the large, peltate species of Gigartinaceae distributed in Argentina, Chile, and along the Antarctic Peninsula. However, phylogenetic analyses of DNA sequences for more than twenty years indicate that two species are passing under the name G. skottsbergii, and both DNA sequences and morpho-anatomy indicate that the species are assignable to an undescribed genus. To formally validate the new genus and species, we performed next generation sequencing (NGS) on the lectotype material of G. skottsbergii to document its genetic identity and obtained its complete mitogenome and partial plastid genome. Phylogenetic analysis of rbcL and cox1 sequences of the lectotype along with recent collections of G. skottsbergii from southern South America and Antarctica, confirmed the generic distinction and the presence of two morphologically similar taxa. We propose Sarcopeltis gen. nov., containing the generitype S. skottsbergii comb. nov. from southern South America, and S. antarctica sp. nov. from the Antarctic Peninsula. Sarcopeltis is characterized by the following suite of features: 1) peg-like secondary haptera that adhere to the substratum, 2) absence of an envelope surrounding each cystocarp, 3) presence of extensive, terminal, tubular gonimoblast filaments that fuse with surrounding vegetative cells, and 4) tetrasporangia formed from secondary filaments entirely in the medulla. This study demonstrates that genetic analysis of type material, together with recently obtained DNA sequences from field collected specimens, can provide clear and objective taxonomic conclusions.

The marine red alga Sciadophycus stellatus E.Y.Dawson (1945) (Figure 1) was described from specimens dredged at 40–50 meters from the Kellett Channel, south shore of Cerros Island (also known as Cedros Island), Baja California, Mexico (Dawson 1945). This uncommon subtidal species occurs in southern California, Baja California, Mexico and Isla Floreana, Galapagos Islands (as Fauchea rhizophylla Taylor) (Dawson 1945, Abbott and Hollenberg 1976, Millar 2001, Aguilar-Rosas et al. 2010). In California, S. stellatus has been collected in San Diego County (UC2003699) and Palos Verdes Peninsula, Los Angeles County (UC1882843), on the mainland coast of southern California and, more commonly, offshore from Santa Catalina (UC1471598), Santa Barbara (UC2034301), Anacapa (WTU-A-012879) and Santa Cruz Islands (UC1965240). In Mexico, in addition to the type locality, it has been collected from Isla Los Coronados (UC1574390), La Bufadora (Aguilar-Rosas et al. 2010), Isla Natividad (UC1882846), Punta Eugenia (US13095) and Bahia Tortugas (US42090), Baja California (distribution records, unless otherwise cited, are based on specimens in herbaria at the University of California at Berkeley [UC], University of Washington [WTU-A], and the Smithsonian Institution [US]).