Etienne Jean Faye

Reinstatement of Grateloupia subpectinata (Rhodophyta, Halymeniaceae) based on morphology and rbcL sequences

Morphological observations and molecular analyses of the north‐western Pacific species of the red algal genus Grateloupia (Halymeniaceae) indicate the presence of an entity, which is somewhat similar in gross morphology to G. asiatica Kawaguchi et Wang but is distinguished from the latter species by some morphological features. These include: (i) a somewhat fleshy texture; (ii) wider and much thicker (4.5–10 mm wide and up to 1300 μm thick) axes, of which an inner cortex consists of more (6–9) cells; (iii) generally longer (up to 17 cm), marginal and surface proliferations that are clearly constricted (terete) at bases; and (iv) much elongated, oblong auxiliary cells. Phylogenetic analysis using the ribulose‐l,5‐bisphosphate carboxylase/ oxygenase (rbcL) gene of G. asiatica and the alga in question shows them to be distantly related and strongly supports the differentiation of these two entities at the species level. Judging from the literature, this entity is actually Grateloupia subpectinata Holmes, which has been placed into synonymy under G. asiatica [as G. filicina (Lamouroux) C. Agardh] or G. prolongata J. Agardh in previous reports, and therefore the Holmes name is reinstated.

A re-evaluation of the taxonomic status of Halophila euphlebia Makino (Hydrocharitaceae) based on morphological features and ITS sequence data

Abstract Identification of Halophila ovalis samples from various parts of the world has long been accompanied by taxonomic uncertainties because of morphological variability. This led to the hypothesis that H. ovalis represents a “collective species” which may include cryptic species. Recent studies applying molecular techniques to the assessment of phylogenetic relationships in the genus Halophila also came to a similar conclusion. In this study, one Halophila species from Japan, previously described as H. euphlebia and later treated as a synonym of H. ovalis, was critically re-examined using molecular phylogenetic analyses of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. Morphological examinations of vegetative and reproductive structures were also undertaken. Results obtained from both morphological and molecular data, combined with a critical review of the relevant literature provide support for recognition of the plant in question as being distinct from H. ovalis. The entity conforms to Makinos description of H. euphlebia. This raises the current number of Halophila species in Japan to three: H. ovalis, H. decipiens and H. euphlebia.

Reassessment of the little-known western African red alga Anatheca montagnei (Gigartinales, Solieriaceae) on the basis of morphology and rbcL sequences

Vegetative and reproductive structures, including the anatomy of young blades, spermatangia, female reproductive organs, post-fertilization development, and tetrasporangia were examined for the little-known red alga, Anatheca montagnei, from Hann Bay, Dakar, Senegal, western Africa, close to the type locality. Carpogonial branches and auxiliary cells develop on cortical filaments in slightly raised nemathecium-like structures. The fertilized carpogonium produces two unbranched, non-septate connecting filaments. The auxiliary cell is one of the intercalary cortical cells, and, together with the surrounding darkly-staining cortical cells, constitutes an auxiliary cell complex that is visible prior to diploidization. The diploidized auxiliary cell cuts off a single gonimoblast initial, which in turn divides to form a placentate cystocarp without distinct enveloping filaments. The cystocarps are contained in cystocarpic protuberances or papillae that are situated on the surfaces and margins of the female blade. Tetrasporangia are cut off laterally from their parental cells and are zonately divided. The alga is characterized by the above-mentioned combination of features but its position within the Solieriaceae was not demonstrated by our rbcL analyses.

Polyopes tosaensis Kawaguchi & Masuda, sp. nov. (Halymeniaceae, Rhodophyta) from Japan

The marine red alga Polyopes tosaensis Kawaguchi & Masuda, sp. nov. (Halymeniaceae, Cryptonemiales) is described from southern Japan. It is distinguished from other members of the genus by the following combination of morphological features: (1) dichotomously or subdichotomously divided, short (2.0 – 3.6 cm in height) blades with segments 2 – 3 mm (occasionally 5 – 8 mm) in width; (2) the rare presence of surface proliferations; (3) the production of reproductive structures over the middle to the upper portions of the blade; and (4) the absence of tetrasporangial nemathecia. This morphological distinction of P. tosaensis is supported by molecular phylogenetic analyses using rbcL gene sequences. Polyopes tosaensis is positioned close to P. hakalauensis (Tilden) Abbott from Hawaii rather than four Japanese species of the genus, P. affinis (Harvey) Kawaguchi & Wang, P. lancifolius (Harvey) Kawaguchi & Wang, P. polyideoides Okamura and P. prolifer (Hariot) Kawaguchi & Wang. The pairwise distances between P. tosaensis and other species of Polyopes range from 10 – 94 bp (0.8 – 7.5%) and are similar to those between species of the large genus Grateloupia [13 – 111 bp (1.0 – 8.8%)] in the Halymeniaceae.

New red alga Meristotheca imbricata (Solieriaceae, Gigartinales) from Japan

A new red alga Meristotheca imbricata Faye et Masuda (Solieriaceae, Gigartinales) was described on the basis of specimens collected from southern Japan. Although this species might have been for a long time included in the concept of M. coacta Okamura, until recently a very poorly known alga, it is distinguished from the latter by the following features: (i) each thallus consists of one primary blade and several secondary blades, the latter arising from the apical or subapical portion of terminal segments of the primary blade; (ii) the individual blades are repeatedly dichotomously divided into linear segments of which margins are neither undulate nor crispate, and are fleshy, imbricate, frequently anastomosing and often acervate; (iii) each tetrasporangial initial is attached by a basal pit‐connection to the parental cell, and the position of the pit‐connection changes from basal to lateral by inward growth of the tetrasporangium; and (iv) the carpogonial branches sometimes have a one‐celled sterile lateral.

Taxonomic features of the red alga Meristotheca coacta (Solieriaceae, Gigartinales)

Vegetative and reproductive structures of the little‐known red alga, Meristotheca coacta Okamura (Solieriaceae, Gigartinales) were described on the basis of specimens collected from three localities in southern Japan, including an island close to the lectotype locality. Meristotheca coacta was shown to be a strongly supported monophyletic clade in our rbcL analyses. The taxonomic features of this species were reassessed. This species is characterized as follows: (i) the thalli consist of relatively thick (300–1400 μm from the uppermost to basal regions), elastic and rose‐red blades; (ii) the blades are irregularly lobed and branched into variously shaped segments with undulate and crispate margins; (iii) tetrasporangial initials are laterally attached to their parental cells and the lateral pit‐connections remain in mature tetrasporangia; (iv) gametophytes are dioecious; (v) carpogonial branches are three‐celled (occasionally two‐ or four‐celled); (vi) a darkly staining auxiliary cell complex is present and recognizable prior to diploidization; and (vii) cystocarps are produced along (or near) the margins of the blades and on the marginal proliferations and lack spinous outgrowths.

Characterization of the edible red alga Meristotheca papulosa (Solieriaceae, Gigartinales) from Japan

The vegetative and reproductive morphology of the edible red alga Meristotheca papulosa (Montagne) J. Agardh (Solieriaceae) was reexamined based on material collected from various localities in Japan. Although the habit of the blades is variable according to the length and width of the axes, the frequency of branching and the abundance of proliferations, rbcL sequence analyses indicate their conspecificity. M. papulosa displays four distinctive reproductive features (presence of an auxiliary cell complex, occurrence of cystocarps on marginal proliferations and the blade surface (although very rare) in addition to the margins of axes, frequent production of spinose outgrowths on the pericarp and tetrasporangial initials typically basally attached to their parental cells) that have not been reported for M. papulosa from other areas. Although these features might warrant recognition of the Japanese entity as a separate species, a better understanding of their possible taxonomic value requires comparisons with M. papulosa from other geographic regions, including the type locality.

Pseudocodium okinawense (Bryopsidales, Chlorophyta), a new species from Okinawa and the first report of the genus from eastern Asia

A new species of the green algal genus Pseudocodium is described on the basis of specimens collected from Okinawa, southern Japan. It differs from the generitype species P. de-vriesii Weber-van Bosse from South Africa, P. australasicum Womersley from Australia and P. floridanum C. J. Dawes & A. C. Mathieson from Florida in its smaller size (1–2 cm in height, axes 0.5–1.0 mm in width) and infrequent branching. Unlike P. de-vriesii and P. australasicum also is its total lack of constricted or articulated axes. Molecular-phylogenetic analyses based on plastid encoded rbcL gene sequences show the Okinawan plants to group with Atlantic P. floridanum but to be specifically distinct owing to substantial base pair differences (88 bp, 11.876%). Remarkable differences in morphometric data, ecological preferences and geographic distribution were also found between them. We thus describe the Okinawan entity as Pseudocodium okinawense E. J. Faye, M. Uchimura et S. Shimada sp. nov. In addition, on the basis of laboratory culture experiments, a diminutive, entirely tubular growth form showing great morphological dissimilarity with field materials is newly observed in the genus, thus adding further details to our understanding of the plants vegetative phenology at early developmental stages.