Giuseppe C. Zuccarello

Victoria University of Wellington · School of Biological Sciences

The genus Aglaothamnion has been separated from Callithamnion based on several characters, most notably the presence of a single nucleus per cell in Aglaothamnion versus multi-nucleate Callithamnion. Few studies have investigated whether these genera are genetically monophyletic. Several species of Aglaothamnion have been reported from Korea, but n...

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium , provided the original work is properly cited. Algae 2024, 39(3): 223-224 https://doi.

Oomycetes are ubiquitous heterotrophs of considerable economic and ecological importance. Lately their diversity in marine environments has been shown to be greatly underappreciated and many lineages of intracellular holocarpic parasites, infecting micro- and macro-algae, remain to be fully described taxonomically. Among them, pathogens of marine r...

The giant kelp Macrocystis pyrifera is in global decline as a result of numerous stressors operating on both local and global scales. It is a species that holds significant value in terms of the ecosystem services that it provides and its application in aquaculture. In order to safeguard, restore and utilize this species, it is essential that a sou...

Oomycete pathogens are one of the most serious threats to the rapidly growing global algae aquaculture industry but research into how they spread and how algae respond to infection is unresolved, let alone a proper classification of the pathogens. Even the taxonomy of the genera Pythium and Olpidiopsis, which contain the most economically damaging...

The continental coasts and remote islands in the high‐latitude Southern Hemisphere, including the subantarctic region, are characterized by many endemic species, high abundance of taxa, and intermediate levels of biodiversity. The macroalgal flora of these locations has received relatively little attention. Filamentous green algae are prolific in t...

Parasitic red algae are an interesting system for investigating the genetic changes that occur in parasites. These parasites have evolved independently multiple times within the red algae. The functional loss of plastid genomes can be investigated in these multiple independent examples, and fine-scale patterns may be discerned. The only plastid gen...

Species of Lobophora (Dictyotales) are distributed throughout the subtropical and tropical seas worldwide. Recent analyses have revealed high species diversity in regions previously presumed to host only a single species, such as the Bismarck Sea, Eastern Pacific, Western Atlantic, Mediterranean Sea, and Greater Caribbean. Here, samples from Veracr...

The paradigm of past climate‐driven range shifts structuring the distribution of marine intraspecific biodiversity lacks replication in biological models exposed to comparable limiting conditions in independent regions. This may lead to confounding effects unlinked to climate drivers. We aim to fill in this gap by asking whether the global distribu...

Four species of Erythrotrichia ( E. biseriata , E. reflexa , E. tetraseriata , E. carnea ) have been reported in Korea, but phylogenetic studies have not been conducted on them. We analyzed two newly collected Erythrotrichia isolates using rbc L DNA sequences and determined their species status using four DNA-based species delimitation methods. One...

Seaweeds (marine macroalgae) are crucial to the functioning of healthy coastal ecosystems and global biogeochemical cycles, and sometimes provide novel solutions to help mitigate climate change. The red seaweed Asparagopsis taxiformis (Bonnemaisoniaceae, Rhodophyta) produces bioactive natural products that, when fed to cattle and sheep, can eradica...

The trend in naming genera based almost exclusively on molecular data, and not on morphological diagnostic characters, is increasing. In bifurcating phylogenetic trees generic cut-offs are arbitrary, but at the bare minimum nomenclatural changes should be supported by multiple phylogenetic methodologies using appropriate models for all the various...

Schizymenia dubyi is reported as a new introduction in Wellington, which already has introduced S. apoda. These species coexist in tidepools and the crustose sporophyte is for the first time reported from this population. The diversity and species status of these two species was explored using mitochondrial, plastid and nuclear markers. Haplotypes...

The term ‘eucheumatoids’ designates a group of genera in the family Solieriaceae that are the source of some of the most valuable algal products in cultivation. While economically important in the tropics, much of its taxonomy is yet to be fully resolved. The eucheumatoid species Mimica arnoldii is a Batesian mimic of corals that was recently trans...

Genetic diversity and distribution patterns of marine macroalgae are increasingly being documented in Southeast Asia. These studies show that there can be significant levels of genetic diversity and isolation between populations on either side of the Thai-Malay Peninsula. Bostrychia tenellla is a common filamentous red seaweed in the region and the...

Taxonomy and diversity of the Gracilariaceae has been increasingly investigated by using integrated morphological and genetic approaches. The Indo-Pacific is likely a hotspot for diversity of these macroalgae. Collections of flattened Gracilaria samples from Natai beach, Andaman coast of Thailand, were morphologically and genetically analysed. Our...

New Zealand’s algal flora is still far from fully explored, and new taxa continue to be discovered. The taxonomy of the red algal order Hildenbrandiales, consisting mostly of crustose members, is controversial as descriptions are largely based on limited morphological features. The order Hildenbrandiales is also in a close, apparently obligate, rel...

Collectively known as eucheumatoids, Eucheuma denticulatum, Kappaphycus alvarezii, K. malesianus, and K. striatus are the main farmed seaweed species in the Philippines. The success of seaweed farming for over five decades in the country is due, in part, to the high diversity of cultivars maintained by the Filipino farmers. Notwithstanding the fact...

Understanding how genetic variation is spatially distributed is necessary for understanding the processes that generate and maintain biodiversity. However, there has been little investigation into the phylogeography of widespread forest trees in Aotearoa New Zealand with studies to date showing little congruence in phylogeographic patterns. Pseudop...

Marine phylogeographic studies have recently shown that historical events, oceanography and ecological factors shape patterns of biodiversity and population connectivity. In southeastern Australia a historical geographic barrier, the Bassian Isthmus, results in deep genetic differentiation between some marine taxa. Using partial mitochondrial cytoc...

Reactive oxygen species (ROS) signaling has a multitude of roles in cellular processes throughout biology. We hypothesized that red algal fertilization may offer an interesting model to study ROS-mediated signaling as the stages of fertilization are complex and unique. We microscopically localized ROS production and monitored the expression of thre...

Exotic species often slip through international borders undetected. Increased global trade has increased the frequency of species introductions. The marine aquarium trade is a significant vector of species introductions, including algal introductions. Molecular barcoding of tropical macroalgae entering the New Zealand aquarium trade was implemented...

Intertidal algae have to cope with diurnally and seasonally fluctuating environmental factors such as salinity, temperature, dehydration, and light. In New Zealand, solar radiation, including the ultraviolet wavelengths, is also an important stress factor for such algae. Therefore, two native ( Bostrychia arbuscula W.H.Harvey [Ceramiales], Champia...

Introductions of macroalgae are becoming more common with increased surveillance and the use of molecular tools to unequivocally identify invaders. We here report two non-indigenous macroalgal species newly confirmed to be present in New Zealand. Pachymeniopsis lanceolata is an irregularly divided foliose blade, first detected in Lyttleton Harbour/...

Fifty–four streams of the Iberian Peninsula were investigated to document the species richness and phylogeny of Batrachospermum and morphologically similar genera, determine phylogenetic affinities of taxa and infer biogeographic trends. Species were identified using morphology and DNA sequence data for the rbcL gene as follows: Batrachospermum gel...

The advent of high‐throughput‐sequencing (HTS) has allowed for the use of large numbers of coding regions to produce robust phylogenies. These phylogenies have been used to highlight relationships at ancient diversifications (subphyla, class), and highlight the evolution of plastid genome structure. The Erythropeltales are an order in the Compsopog...

The endemic Cladophoraceae of Lake Baikal are a group with high species richness, monophyly, and apparently recent speciation, making them ideal for the study of the genetic structure of an alga in this large freshwater environment. We analysed the population genetics of Chaetomorpha (= Ch.) moniliformis, Cladophora (= Cl.) compacta and Cl. kursano...

Diverse sex determination mechanisms have been reported in eukaryotes, but little is known about the genetic pathways leading to sex determination in red algae. Sex‐specific genes that could be involved in sex determination and sexual differentiation were investigated in the red alga Bostrychia moritziana by analyzing the transcriptomes of various...

Identification of foliose red algae is particularly problematic as many of the characters used, such as general overall habit, colour, and texture, are often dependent on environmental or developmental characteristics of the specimen in question. One foliose red algal genus that has received little attention and is quite common in parts of New Zeal...

Indonesia is a major player in the aquaculture of red algae, especially carrageenan producing ‘eucheumatoids’ such as Kappaphycus and Eucheuma. However, many current trade names do not reflect the evolutionary species and updated taxonomy, this is especially the case for eucheumatoid seaweeds that are highly variable in morphology and pigmentation....

Eucheuma perplexum is based on specimens from Patotsu, Taiwan. This species is morphologically difficult to distinguish from other eucheumatoids that exhibit a broad range of habit forms, particularly Betaphycus gelatinus, Eucheuma denticulatum, and E. serra. Here, the Philippine and topotype specimens of E. perplexum have been examined, their dist...

Ancient lakes are centres of biological diversification that hold many examples of adaptive radiation and species flocks. The recently discovered species flock of Cladophoraceae in Lake Baikal is a group of green algae that exhibit low genetic divergence in ribosomal markers (LSU, SSU, and ITS), but wide morphological differentiation. Microsatellit...

Molecular studies have reported the co‐existence of two species of Agarophyton in New Zealand: the newly described A. transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more wide‐spread A. chilense. Here we compared the distribution, genetic diversity, and structure of both Agarophyton species thro...

Ancient lakes are centres of adaptive radiation and speciation. The Cladophoraceae endemic to ancient Lake Baikal is a morphologically diverse group nested within Rhizoclonium that may represent a case of sympatric speciation. Recent research using ribosomal DNA markers indicates that these taxa form a monophyletic group but was not able to resolve...

The Gracilariaceae is a species-rich family, with a number of members having high commercial value as sources of agar. Members of this family are also known for their phenotypic plasticity and convergent morphologies, resulting in considerable taxonomic confusion. Over the past two decades, two species of Agarophyton (previously part of Gracilaria)...

Comparative organelle genome studies of parasites can highlight genetic changes that occur during the transition from a free‐living to a parasitic state. Our study focuses on a poorly studied group of red algal parasites, which are often closely related to their red algal hosts and from which they presumably evolved. Most of these parasites are pig...

A new species of Polycoelia, P. kurariirapa, is described from the Three Kings Islands/Manawatāwhi, representing the first record of the genus in New Zealand. Polycoelia includes two species from Australia, P. laciniata (generitype) and P. fastigiata, and one from South Africa, P. harveyana. Polycoelia kurariirapa shares with the two Australian spe...

Salomaki and Lane (2019) proposed a new terminology to group red algal parasites either as parasites containing their own (native) reduced plastid: ‘archaeplastic’ (allied to the old designation ‘alloparasite’) or parasites that contain only a host plastid: ‘neoplastic’ (similar to the older term ‘adelphoparasite’). We believe this is premature. Th...

Red algae of the genus Plocamium have been a rich source of halogenated monoterpenes. Herein, a new cyclic monoterpene, costatone C (7), was isolated from the extract of P. angustum collected in New Zealand, along with the previously reported (1E,5Z)-1,6-dichloro-2-methylhepta-1,5-dien-3-ol (8). Elucidation of the planar structure of 7 was achieved...

Flattened Gracilaria species are widely distributed along the coasts of the South China Sea with more than 20 species recorded. Within the South China Sea, Gracilaria mammillaris has only been reported from Vietnam, but this species is likely restricted to the western Atlantic. This study aimed to reevaluate the taxonomic status of Vietnamese speci...

The most rapidly expanding areas for seaweed production in the world are the tropics, including Indonesia, yet these areas are also where molecular identification of local marine flora has only been sporadically employed. Furthermore, a goal for the Government of Indonesia is to diversify the types of seaweed that are being utilized, targeting valu...

Parasitic red algae grow only on other red algae and have over 120 described species. Developmental studies in red algal parasites are few, although they have shown that secondary pit connections formed between parasite and host and proposed that this was an important process in successful parasitism. Furthermore, it was recorded that the transfer...

Over 100 species of red algae have been described as parasites on other red algae, but the majority show some degree of pigmentation. This raises the question of their parasitic status, especially their abilities to photosynthesize and their dependence on their host for fixed carbon. Are they considered parasites only based on morphological charact...

Intertidal rocky shore ecosystems are affected by steep environmental gradients such as fluctuating solar irradiation and salinity along the marine-terrestrial interface. The eulittoral red alga Pyropia plicata (Bangiales) is endemic and abundant to coastal regions of New Zealand and almost unstudied in terms of ecophysiological performance under r...

Lake Baikal, the oldest lake in the world, is home to spectacular biodiversity and extraordinary levels of endemism. While many of the animal species flocks from Lake Baikal are famous examples of evolutionary radiations, the lake also includes a wide diversity of endemic algae that are not well investigated with regards to molecular‐biological tax...

Many brown macroalgal species are difficult to identify because of limited morphological differentiation and/ or high levels of plasticity. Molecular methods for distinguishing species coupled with morphological examination have been useful in clarifying species status in many groups. Cystophora is a species-rich, morphologically complex brown alga...

Studies in New Zealand on the family Kallymeniaceae have revealed greater diversity than had been reported previously, including samples identified as species of the genus Callophyllis. Specimens from New Zealand referred to as Callophyllis variegata were distantly related to the type species from Chile. Samples identified as Judithia laingii (a.k....

There are over 120 species of red algal parasites (Florideophyceae) but they are often overlooked due to their small size and patchy distribution. Red algal parasites have mostly been described as independent genera but recent phylogenetic studies have shown that parasites are related to free-living relatives, often their hosts, and have been named...

Molecular methods have greatly aided in discovering new diversity in many cryptic algal groups. Molecular-assisted species discovery has focused morphological analyses on previously overlooked taxa, leading to a better understanding of diversity and evolutionary patterns. The Yucatan Peninsula, as a junction of North and South American Atlantic flo...

The discovery of a plethora of cryptic species in many algal groups has led to speculation as to the causes of this observation and has affected taxonomy, with reluctance to give names to species that look identical. While this is defensible for monophyletic cryptic species complexes, both our understanding of similar morphologies (crypsis) and nom...

A library of expressed sequence tags (ESTs) was derived from the economically important Rhodophyta species Eucheuma denticulatum. This small scale EST library represents the first look at the set of genes expressed in any Eucheuma species. A total of 311 clones were analyzed. These 311 sequences clustered into 143 unigenes. Thirty-two of the 143 un...

Distribution patterns and genetic diversity of Caloglossa species have been studied in various regions but are still poorly understood around the tropical western Pacific where many marine organisms show high species richness. We explored the diversity of Caloglossa species in New Ireland, Papua New Guinea using morphological and genetic analyses....

Studies of the taxonomy and diversity of flattened Gracilaria species which occur commonly in coastal areas of Thailand are few and underestimate species richness. Recently, flattened Gracilaria plants were collected along the west coast of southern Thailand (Andaman Sea). We describe a new flattened Gracilaria species, Gracilaria coppejansii Muang...

Collections of Batrachospermales from 13 stream sites in North America (Canada and United States), Europe (Spain) and Asia (China) were examined. Phylogenetic analyses of sequences data from the plastid-encoded ribulose 1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) and the mitochondrial-encoded cytochrome oxidase 1 gene barcode r...

Geographic distributions of pathogens are affected by dynamic processes involving host susceptibility, availability and abundance. An oomycete, Pythium porphyrae, is the causative agent of red rot disease, which plagues Pyropia farms in Korea and Japan almost every year and causes serious economic damage. We isolated an oomycete pathogen infecting...

Wittrockiella is a small genus of filamentous green algae that occurs in habitats with reduced or fluctuating salinities. Many aspects of the basic biology of these algae are still unknown and the phylogenetic relationships within the genus have not been fully explored. We provide a phylogeny based on three ribosomal markers (ITS, LSU and SSU rDNA)...

Halimeda macroloba is a common widespread and morphologically variable species in the Indo-Pacific Ocean. A series of morphometric data (16 morphological and 46 anatomical variables) and the chloroplast-encoded tuf A gene were examined to explore the morphological and genetic variations within the species and to better determine species boundaries...

The thecate filose amoeba Paulinella chromatophora is a good model organism for understanding plastid organellogenesis because its chromatophore was newly derived from an alpha-cyanobacterium. Paulinella chromatophora was the only known photosynthetic Paulinella species until recent studies that suggested a species level of diversity. Here, we desc...

Red algal parasites are diverse organisms that are unusual due to the fact that many are closely related to their hosts. Parasitism has developed many times within different red algal groups, but the full extent of parasite biodiversity is unknown, as parasites are easily overlooked due to their small size and often low abundance. Additionally, the...

Chaetomorpha melagonium is a morphologically distinct species of green algae that occurs throughout the North Atlantic, the North Pacific and the Arctic Ocean. In this study, we analyzed the intraspecific genetic diversity among 14 samples of C. melagonium from across the distribution range based on nuclear large subunit ribosomal DNA (LSU rDNA) an...

Floating debris provides substrates for dispersal of organisms by ocean currents, including algae that thrive on plastics. The 2011 earthquake and tsunami in Tohuku, Japan resulted in large amounts of debris carried by the North Pacific Current to North America from 2012 to 2016. In 2015-2016, the plastics in the debris bore a complex biota includi...

Phylogeographic studies can contribute to our understanding of the evolutionary forces acting on the patterns of genetic variation and the evolutionary history of species. The Hydropuntia cornea/Hydropuntia usneoides species complex consists of two common species of red algae in the Gulf of Mexico and Caribbean Sea. Both species exhibit high phenot...

Molecular-assisted alpha taxonomy has provided novel ways of exploring biodiversity, and is of great help in taxa where morphology alone is not sufficient to ensure accurate species recognition or delimit species boundaries. Here, we use this approach to assess the taxonomy of Padina Adanson (Dictyotales, Phaeophyceae), a common brown algal genus i...

The taxonomy of the Cladophoraceae, a large family of filamentous green algae, has been problematic for a long time due to morphological simplicity, parallel evolution, phenotypic plasticity and unknown distribution ranges. Partial large subunit (LSU) rDNA sequences were generated for 362 isolates, and the analyses of a concatenated dataset consist...

Sympatric coexistence of cryptic species, indistinguishable morphological taxa, has increasingly been detected on the basis of molecular data. This discovery raises the interesting question of how cryptic species can coexist, as hypothetically they would need identical ecological resources. The red alga Bostrychia intricata is commonly found along...