Tae Oh Cho

Gayliella gen. nov in the tribe Ceramieae (Ceramiaceae, Rhodophyta) based on molecular and morphological evidence

On the basis of comparative morphology and phylogenetic analyses of rbcL and LSU rDNA sequence data, a new genus, Gayliella gen. nov., is proposed to accommodate the Ceramium flaccidum complex (C. flaccidum, C. byssoideum, C. gracillimum var. byssoideum, and C. taylorii), C. fimbriatum, and a previously undescribed species from Australia. C. transversale is reinstated and recognized as a distinct species. Through this study, G. flaccida (Kützing) comb. nov., G. transversalis (Collins et Hervey) comb. nov., G. fimbriata (Setchell et N. L. Gardner) comb. nov., G. taylorii comb. nov., G. mazoyerae sp. nov., and G. womersleyi sp. nov. are based on detailed comparative morphology. The species referred to as C. flaccidum and C. dawsonii from Brazil also belong to the new genus. Comparison of Gayliella with Ceramium shows that it differs from the latter by having an alternate branching pattern; three cortical initials per periaxial cell, of which the third is directed basipetally and divides horizontally; and unicellular rhizoids produced from periaxial cells. Our phylogenetic analyses of rbcL and LSU rDNA gene sequence data confirm that Gayliella gen. nov. represents a monophyletic clade distinct from most Ceramium species including the type species, C. virgatum. We also transfer C. recticorticum to the new genus Gayliella.

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF SPECIES OF THE GENUS CENTROCERAS (CERAMIACEAE, CERAMIALES), INCLUDING TWO NEW SPECIES 1

Centroceras clavulatum (C. Agardh) Montagne is widely reported as being a prime example of a cosmopolitan red algal species. Instead, C. clavulatum is here determined as restricted to northern Chile, Peru, southern California, southern Australia, and New Zealand. Specimens identified using the current species concept for “C. clavulatum” fall into nine morphological groups that correspond to highly supported clades in phylogenetic analyses. Three of these clades correspond to the resurrected species Centroceras gasparrinii (Meneghini) Kützing, C. hyalacanthum Kützing, and C. micracanthum Kützing. Two others are recognized as new species: Centroceras rodmanii sp. nov. from southern Chile, which is characterized by hooked spines arranged in a whorl at the node, a spine or flattened gland cell cut off from the first cortical initials, and a single acropetal cortical cell issued from the second cortical initials; and C. tetrachotomum sp. nov. from South Africa, which has a tetrachotomous branching pattern, straight spines in a whorl, an acropetal cortical cell and a spine or a flattened gland cell cut off from the first cortical initials, and a two‐celled acropetal filament cut off from the second cortical initials. Three additional species from South Africa are also recognized as distinct species. All phylogenetic analyses of the rbcL gene, LSU rDNA, and SSU rDNA were consistent with the vegetative and tetrasporangial morphological distinctions, thus supporting the resurrection of three species and the description of two new species.

Two creeping Ceramium species (Ceramiaceae, Rhodophyta) from the Florida Keys: C. reptans sp. nov. and recircumscription of C. codii (Richards) Mazoyer

Tae Oh Cho and Suzanne Fredericq. 2006. Two creeping Ceramium species (Ceramiaceae, Rhodophyta) from the Florida Keys: C. reptans sp. nov. and recircumscription of C. codii (Richards) Mazoyer. Phycologia 45: 495–504. DOI: 10.2216/05-44.1 On the basis of comparative morphology, a new creeping Ceramium species with incomplete and narrow nodal cortication, C. reptans sp. nov. is described from the Florida Keys, USA, where it co-occurs epiphytically with C. codii on the same host, Hypnea spinella. Ceramium reptans sp. nov. is recognized by a prostrate axis producing unbranched upright axes dorsally; five periaxial cells per axial cell; three cortical cells cut off per periaxial cell, with the first acropetal cortical cell becoming the pseudoperiaxial cell that extends longitudinally parallel to the level of neighboring periaxial cells, a second acropetal and third basipetal horizontal cortical cell; and cruciately divided tetrasporangia in whorls bulging from a single node appressed to the contiguous node below on upright axes, 3–6 segments below the apex. Ceramium codii, described from Bermuda, is recognized by a prostrate axis producing unbranched, upright axes dorsally, four periaxial cells per axial cell, three cortical cells cut off per periaxial cell with the basipetal cortical cell cut off horizontally on the prostrate axis, and 1–2 tetrahedrally divided tetrasporangia produced per periaxial cell. Among the described creeping Ceramium species; C. codii, C. bisporum, C. cingulatum, C. cingulum, C. dorsiventrale, C. incospicuum, C. jolyi, C. luetzelburgii, C. procumbens, C. poeppigianum, C. punctiforme, C. serpens, and C. tenerrimum var. brevizonatum f. repens, none has the characteristic pseudoperiaxial cells of C. reptans. Ceramium codii may not be a widespread species as is widely reported in the literature.

Neosiphonia peruviensis sp. nov. (Rhodomelaceae, Rhodophyta) from the Pacific coast of South America

Abstract Approximately 29 species of Neosiphonia are currently recognized worldwide. We describe our unidentified samples collected from the Pacific coast of South America as a new species, N. peruviensis sp. nov., based on morphological and molecular data. Neosiphonia peruviensis sp. nov. is characterized by erect and prostrate thalli, rhizoids cut off from proximal ends of pericentral cells by cross walls, six pericentral cells that are totally ecorticate, abundant trichoblasts forked once or twice, prominent scar cells and tetrasporangia spirally arranged. Our new species is similar to several Neosiphonia/Polysiphonia species having more than four pericentral cells: N. notoensis, N. porrecta, “N. tepida”, N. teradomariensis, and “P. forfex”. However, N. peruviensis sp. nov. is distinguished from these similar species by having six pericentral cells through all of the thallus. Phylogenetic analyses of rbcL indicate that our N. peruviensis is placed in genus Neosiphonia and is also distinguishable from other Neosiphonia species.

Polysiphonia dokdoensis sp. nov. (Rhodomelaceae, Ceramiales) based on a population previously known as Polysiphonia atlantica sensu Kim and Lee from Korea

Abstract The genus Polysiphonia Greville is characterized by having four ecorticated pericentral cells, rhizoids in open connection with the pericentral cells, four-celled carpogonial branches, spermatangial branches replacing the whole trichoblast, and tetrasporangia in straight series. Polysiphonia dokdoensis sp. nov. collected from Dokdo, Korea is here described as a new species on the basis of morphological and molecular data. Polysiphonia dokdoensis is characterized by having four ecorticated pericentral cells, unicellular rhizoids in open connection with pericentral cells, scar cells placed between two pericentral cells, an alternating arrangement of unilateral branch pairs, and tetrasporangia in straight series. The alternating arrangement of unilateral branch pairs and the placement of the scar cell between two pericentral cells are recognized as main characters to identify P. dokdoensis. Polysiphonia dokdoensis is morphologically identical to “P. atlantica” sensu Kim and Lee, which is now recognized as P. dokdoensis sp. nov. and distinguished from the authentic European P. atlantica by the distinguishing morphological character states. Phylogenetic analyses of rbcL confirm the placement of the new taxon as a distinct species in Polysiphonia sensu stricto.

Wilsonosiphonia gen. nov. (Rhodomelaceae, Rhodophyta) based on molecular and morpho-anatomical characters

Morphological, anatomical, and molecular sequence data were used to assess the establishment and phylogenetic position of the genus Wilsonosiphonia gen. nov. Phylogenies based on rbcL and concatenated rbcL and cox1 loci support recognition of Wilsonosiphonia gen. nov., sister to Herposiphonia. Diagnostic features for Wilsonosiphonia are rhizoids located at distal ends of pericentral cells and taproot‐shaped multicellular tips of rhizoids. Wilsonosiphonia includes three species with diagnostic rbcL and cox1 sequences, Wilsonosiphonia fujiae sp. nov. (the generitype), W. howei comb. nov., and W. indica sp. nov. These three species resemble each other in external morphology, but W. fujiae is distinguished by having two tetrasporangia per segment rather than one, W. indica by having abundant and persistent trichoblasts, and W. howei by having few and deciduous trichoblasts.

Polysiphonia freshwateri sp. nov. and Polysiphonia koreana sp. nov.: two new species of Polysiphonia (Rhodomelaceae, Rhodophyta) from Korea

Polysiphonia sensu lato comprises approximately 200 species, which are currently assigned to several different genera. To date, one of these genera, namely, Polysiphonia, has been reported to have 17 species. Here, we describe for the first time P. freshwateri sp. nov. and P. koreana sp. nov. from Uljin and Ulleung Island, Korea, based on morphological and molecular evidence. Polysiphonia freshwateri sp. nov. and P. koreana sp. nov. are characterized by having the typical Polysiphonia features. Polysiphonia freshwateri sp. nov. is further characterized by having abundant trichoblasts, conspicuous scar cells, and tetrasporangia arranged in spiral series. Polysiphonia koreana sp. nov. is further characterized by having very scarce scar cells placed between two pericentral cells, from which cicatrigenous branches arise. The results of our rbcL sequence analyses support the taxonomic placement of P. freshwateri sp. nov. and P. koreana sp. nov. within Polysiphonia.

Neosiphonia baliana sp. nov. and N. silvae sp. nov. (Rhodomelaceae, Rhodophyta) from Bali, Indonesia

Abstract Worldwide, 32 species have been recognized in the genus Neosiphonia. We describe two new species of the genus from Bali, Indonesia, based on morphological and molecular data. Neosiphonia baliana sp. nov. is recognized by having rhizoids cut off from the proximal end of pericentral cells, axes with five pericentral cells, axes ecorticate throughout, the absence of trichoblasts and scar cells, the straight arrangement of tetrasporangia, and spermatangia arising from a basal cell without the production of trichoblasts. Neosiphonia silvae sp. nov. is characterized by having rhizoids cut off from the proximal end of pericentral cells, axes with four pericentral cells, axes ecorticate throughout, production of abundant trichoblasts near the apices, prominent scar cells, an exceedingly prominent apical cell at axis tips, and one or two tetrasporangia per branch. Phylogenetic analyses of rbcL indicated that our N. baliana sp. nov. and N. silvae sp. nov. fall in the genus Neosiphonia, and we distinguish them on the basis of morphological features from other congeneric species.

First record of Neosiphonia echinata (Rhodomelaceae, Rhodophyta) in the South Pacific: an introduced species in Southeast Asia.

Abstract Neosiphonia echinata, a well-known western Atlantic species, is here reported for the first time from Indonesia and this extends its distribution into Southeast Asia. Neosiphonia echinata was collected from Sulawesi, Indonesia as an epiphyte on Kappaphycus alvarezii and growing on ropes in a culture farm. We also collected this species from Florida, USA, and then compared their morphology and molecular data. Neosiphonia echinata is identified by having erect main filaments arising from prostrate filaments, numerous rhizoids cutting off from the proximal end of pericentral cells by a cross wall, four pericentral cells throughout the thallus, ecorticate axes, very long and abundant trichoblasts more than twice forked, abundant adventitious laterals, procarps with four-celled carpogonial branches, and a spiral arrangement of tetrasporangia. Our phylogenetic analyses of rbcL and cox1 indicate that N. echinata found in Indonesia was very closely related to material from the Western Atlantic Ocean. Neosiphonia echinata may be added as an introduced species to the Indonesian marine flora. The shipping routes western Atlantic-Mediterranean-Indonesia and western Atlantic-Pacific Ocean-Indonesia might be considered as possible pathways of introduction as a consequence of ballast water and hull fouling.

Two new species of Centroceras (Ceramiaceae, Rhodophyta) from KwaZulu-Natal, South Africa

Two distinct species of Centroceras from South Africa that were previously referred to as Centroceras sp. 2 and Centroceras sp. 3 on the basis of comparative rbcL sequence analysis are here newly described on the basis of vegetative morphology. Centroceras hommersandii sp. nov. is characterized at the nodes by an elongated cortical cell derived from the second cortical initials, a flattened gland cell and a cortical cell cut off from the first cortical initials, straight spines, 13–14 periaxial cells, and by tetrasporangia not associated with involucral branchlets. Centroceras natalensis sp. nov. is characterized at the nodes by an ovoid cortical cell on the second cortical initial, a flattened gland cell and a cortical cell produced from the first cortical initial, straight spines, and 12–14 periaxial cells. Other species of Centroceras examined possess either only a flattened gland cell cut off from the first cortical initials (in C. clavulatum, C. rodmanii, C. tetrachotomum), or an ovoid gland cell with a cortical cell (in C. gasparrinii, C. hyalacanthum, C. internitens, C. micracanthum). Centroceras hommersandii sp. nov. is also distinguished by an elongated acropetal cortical cell formed only on the second cortical initial, whereas other species (C. hyalacanthum, C. internitens, C. micracanthum) have elongated acropetal cells present on both the first and second cortical initials. A key to the South African species of Centroceras is provided.