Since the initial western Atlantic collections in the Florida Keys and Bermuda during the mid-1800s, Helminthocladia calvadosii sensu auct. (type locality: Calvados, France) has also been identified from the Caribbean Sea and as far south as northern Brazil. Prior to this study, collections from the eastern and western Atlantic had not been compared using molecular-assisted alpha taxonomy. Recent winter-spring collections of H. calvadosii from Bermuda display an overall habit that is distinct from eastern Atlantic plants of the same species, appearing more similar to H. reyesii (type locality: Canary Islands). Utilizing markers for the mitochondrial COI-5P, we have elucidated the relationships between Bermudian isolates and H. calvadosii from near the type locality, verifying their generic placement within the Liagoraceae and demonstrating their distinctiveness. Using vegetative and reproductive characteristics, we conclude that specimens historically identified as H. calvadosii from Bermuda represent a novel species, and propose Helminthocladia kempii Popolizio, C.W. Schneid, et Chengsupanimit sp. nov. for them.

COI-5P / Helminthocladia calvadosii / Helminthocladia kempii sp. nov. / Liagoraceae / Nemaliales / Rhodophyta

In this paper, we show morphological features of two marine planktonic diatoms that are phylogenetically related, as suggested by molecular studies: Bellerochea malleus and Helicotheca tamesis. In order to study Bellerochea malleus specimens of the species were isolated from samples collected from marginal coral reefs located in the southern portion of Puerto Rico and cultured in the laboratory. Specimens of the species Helicotheca tamesis were isolated from net phytoplankton samples collected from the tropical Mexican Pacific and also cultured in the laboratory. The two species were examined by means of light and scanning electron microscopy. The morphology of Bellerochea malleus agrees well with previous reports: cells arranged in relatively long chains, united by the horn-shaped apical elevations, elliptical valves (not triangular) with depressed valve face bearing an eccentric annulus, from which numerous costae radiate, formation of costate ocelli, and one eccentric or marginal protruded and tubular rimoportula per valve. Helicotheca tamesis also shows the typical morphological features of this species: cells are solitary or form long and distinctly twisted chains, with no apparent apertures between sibling valves, valves are linear to elliptical, weakly silicified and flat. Furthermore, we found one conspicuous and protruded rimoportula per valve, located eccentrically or marginally (not central as previously described), consisting of an elliptic tubular structure. The cingulum is composed of numerous half-bands and segmented copulae. This study compares the morphology of these two species, with a special emphasis on the structure of the rimoportulae.

Bellerochea / Diatoms / Helicotheca / Morphology / Phytoplankton / Rimoportulae

The genus name Gloeobacter with the single (= type) species Gloeobacter violaceus (Cyanophyta, Cyanoprokaryota, Cyanobacteria) was described by Rippka, Waterbury et Cohen-Bazire (Arch. Microbiol. 100: 419–436, 1974). However, this is not a validly published name and so it currently has no standing under the botanical International Code of Nomenclature (ICN, Mc Neil et al. 2012) or the International Code of Nomenclature of Prokaryotes (ICNB/ICNP, Lapage et al. 1992). The lack of valid publication of the genus name causes many problems in the taxonomy of this phylogenetically and experimentally important cyanophyte/cyanobacterium. The lack of thylakoids, a feature unique among all known cyanobacteria, as well as the phylogenetic position of the representative of this genus, warrant valid publication of this generic name. The type strain was deposited in the collection PCC in Paris under the number PCC 7421 and later introduced into numerous other strain collections; however, the dried specimens were not yet conserved. The type strain is cited as holotype in Castenholz (Bergey's Manual, 2001). We here propose validation of the names Gloeobacter Rippka et al. 1974, gen. nov (type: Gloeobacter violaceus) and Gloeobacter violaceus Rippka et al. 1974, sp. nov., utilising the description by Rippka et al. reproduced here, and supported by the exsiccate BRNM No. HY 2366 (under the rules of the botanical Code of Nomenclature - ICN), using exsiccate from the type strain 7421 (PCC 7421^T = ATCC 29082^T).

Cyanophyceae / Cyanobacteria / Gloeobacter / taxonomy / validation

Pseudobranchioglossum gen. nov. and the sole species Ps. senegalense sp. nov., names proposed but not validated by Bodard, are herein validated with descriptions, the required citation of the Holotype, and the place where it has been deposited (PC). This new taxon of Delesseriaceae is known from locations on the coast of Senegal, West Africa.

Ceramiales / Delesseriaceae / Holotype / Pseudobranchioglossum / Rhodophyta / Senegal / taxonomy / validation

A species previously confused with Ahnfeltiopsis devoniensis in Ireland and with Gymnogongrus crenulatus in eastern Canada and north-eastern USA has remained undescribed because of its cryptogenic origin. Our published research suggested a trans-Atlantic introduction, possibly with ship ballast rock, but the relationship with A. leptophylla from California required further investigation and a North Pacific origin was possible. Here, we report that 34 samples of this species from Northern Ireland (UK), New Hampshire (USA) and New Brunswick (Canada) were genetically identical at the cox2–3 spacer locus, consistent with a recent introduction. By contrast, in A. leptophylla, four haplotypes were found in 9 samples from three sites in California. This species (as G. crenulatus) was recently discovered in the North Pacific for the first time, during surveys in British Columbia for the Canadian Barcode of Life Project. Phylogenetic analysis of plastid-encoded rbcL and mitochondrial cox1 gene sequences separate it from A. leptophylla in a robust clade with two North Pacific taxa, Gymnogongrus chiton (M.A. Howe) P.C. Silva et De Cew, and “Ahnfeltiopsis gigartinoides”, both from California. It is here described as a new species in a new genus, Fredericqia deveauniensis, gen. et sp. nov. The two other members of the genus are Fredericqia chiton (M.A. Howe) comb. nov. and Fredericqia decewii, sp. nov., previously known as Ahnfeltiopsis gigartinoides but not conspecific with the type from Mexico. Fredericqia species form extensive basal holdfasts giving rise to terete or compressed erect gametophytic axes 50–300 mm high. Procarps develop either into compact cystocarps with multiple ostioles but no mucilaginous sheath, or externally protruding carpotetrasporophytes (in F. chiton). Life histories are potentially heteromorphic (erect gametophytes and crustose sporophytes with compact, coalescent hypobasal tissue, forming catenate sporangia, both reproduce apomictically in F. deveauniensis), or carpotetrasporangial. F. deveauniensis differs from the other members of the genus in forming internal cystocarps on flattened blades.

Ahnfeltiopsis / DNA barcoding / Gymnogongrus / introduction / molecular systematics