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Ongoing taxonomic studies of Australian marine algae have led to the recognition of a new species of the green algal genus Rhipilia , here named R. psammophila Huisman & Verbruggen. The new species is unusual for this typically tropical genus in growing in the colder temperate waters of southern Australia and can be distinguished from its congeners by the morphology of its laterally adhering siphons, in addition to unique molecular sequences (rbc L and tuf A). In molecular analysis, the new species is sister to the southern Australian Chlorodesmis baculifera , which is here transferred to Rhipilia and represents the third species in the genus with laterally unattached, free siphons, a feature that previously would have excluded it from the genus. Lateral gametangia are described for R. psammophila and represent the first record of reproduction in Rhipilia. A species of green algae, Rhipilia psammophila, growing in south-western Australia. Taxonomic studies of Australian seaweeds are showing a wealth of undiscovered species. In this paper, a new species of green seaweed, Rhipilia psammophila , is described for specimens from south-western Australia, and a closely related species currently known as Chlorodesmis baculifera is transferred to Rhipilia. Morphological features are proving unreliable in distinguishing genera in this group and molecular analyses are essential. (Photograph by John Huisman.) [ABSTRACT FROM AUTHOR]

Small red algal morphologically variable blades have been extensively collected from Hawaiian reefs, but for many specimens their taxonomy remains poorly understood. In surveys of the Papahānaumokuākea Marine National Monument (PMNM) and Main Hawaiian Islands (MHI), we discovered two taxa of undescribed small (< 5 cm) red blades that matched the genera Psaromenia and Meredithia, based on morphology and molecular analyses. Neither genus has been previously recorded in the Hawaiian Islands, and neither group of specimens matched currently described species in these two genera. Accordingly, these specimens are described here as new species within the family Kallymeniaceae. Psaromenia laulamaula sp. nov., exclusively found at mesophotic depths (83–94 m) in PMNM, is easily distinguished from other members of the genus by its comparatively large, procarpic carpogonial branch system and solitary obovate pink-to-magenta blades. Conversely, Meredithia hawaiiensis sp. nov., occurring in both shallow (0–17 m) and mesophotic depths (55 m), has high morphological plasticity, with characters that overlap with other Meredithia species, and can only be distinguished based on DNA sequences. This study provides additional evidence of the extent of diversity in the Kallymeniaceae that is poorly characterized from mesophotic depths and provides further evidence that members of the macroalgal flora contain overlooked biodiversity. [ABSTRACT FROM AUTHOR]

Halymenia latifolia from Atlantic Europe and the Mediterranean Sea has been shown in previous studies to be a distinct evolutionary clade, separate from the Halymenia clade that includes the generitype. Halymenia latifolia has recently been transferred to the genus Nesoia. Phylogenetic analyses based on rbcL sequences of European (Atlantic and Mediterranean) specimens of putative N. latifolia showed that two species were present, one representing an undescribed species (Nesoia mediterranea sp. nov.) and one corresponding to genuine N. latifolia. In order to establish morphological taxonomic characteristics that distinguish these two cryptic species, we examined and described their reproductive structures and postfertilisation stages. In addition, our results showed that the development of the carpogonial branch ampullae pre- and postfertilisation can be used to separate Nesoia from Halymenia, because the basal nutritive cell cluster found in Halymenia is lacking in Nesoia. Other lesser known species currently placed in the genus Halymenia from Atlantic Europe and the Mediterranean Sea require molecular characterisation and examination of their reproductive morphology as part of further revision of the genus. [ABSTRACT FROM AUTHOR]

Molecular characterisation (using tufA and rbcL DNA sequences) of newly collected specimens of the genus Caulerpa in southern Australia identified 24 species and one variety, which, with the addition of four species and one variety recorded previously but not found during the present study, brings the total number of Caulerpa taxa in the region to 28 species and two varieties. Three new species are described based on molecular and morphological data: Caulerpa crispata comb. & stat. nov. (for C. longifolia f. crispata), Caulerpa coppejansii sp. nov., and Caulerpa perplexa sp. nov. Caulerpa coppejansii is a tropical West Pacific species and is included here due to its similarity to the southern Australian Caulerpa sedoides. Caulerpa perplexa is found in Western Australia and is a cryptic sister species of C. parvifolia Harvey from eastern Australia. The name Caulerpa muelleri is reinstated for C. flexilis var. muelleri. A new name, Caulerpa lucasii nom. nov., is proposed for Caulerpa annulata Lucas nom. illeg., a taxon shown to be distinct from Caulerpa hodgkinsoniae. Caulerpa corynephora and Caulerpa fergusonii are newly reported from the region, and a population of the potentially invasive Caulerpa cylindracea is reported from Portland, Victoria. An updated nomenclature is provided and reference tufA sequences are proposed, as well as an updated identification key for southern Australian Caulerpa species. [ABSTRACT FROM AUTHOR]

Many traditional genera of the Halymeniaceae turn out to be poly- or paraphyletic based on molecular phylogenies. The genus Halymenia is no exception. In this study, we provide a detailed characterization of the vegetative and reproductive morphology of the generitype of Halymenia, H. floresii, based on specimens from the north-western Mediterranean Sea. In addition we describe a newly detected clade (Neofolia rosea gen. et sp. nov.) which was previously confused with ‘Halymenia latifolia’ from the north-eastern Atlantic Ocean and the western Mediterranean Sea. The development of auxiliary cell ampullae in Neofolia and Halymenia is similar, namely, ampullae consist of three orders of branched filaments after diploidization of the auxiliary cell and form a weak pericarp comprised only of elongated and branched ampullary filaments. The auxiliary cell is always differentiated from the first cell of the third-order ampullary filament. This pattern differs significantly from previous descriptions of the female reproductive system of Halymenia, in which the auxiliary cell is said to be the third cell of the primary ampullary filament and few secondary and tertiary ampullary filaments are produced from the primary ampullary filament before diploidization of the auxiliary cell. Neofolia primarily differs from Halymenia in the absence of a cellular cluster (= nutritive filaments), which is present in the basal parts of the carpogonial branch ampullae in Halymenia. Moreover, auxiliary cell ampullary filaments in Neofolia are much shorter (6-7 cells long) than those found in Halymenia (9-13 cells long), and the secondarily generated connecting filaments are issued from the basal cells of the ampullary filaments in Halymenia, whereas they are produced from the fusion cell in Neofolia. Resolving the polyphyly of Halymenia will require a re-examination of the species of ‘Halymenia’ that are not clustered with the generitype. [ABSTRACT FROM AUTHOR]