Prorocentrum shikokuense Hada and P. donghaiense Lu are junior synonyms of P. obtusidens Schiller, but not of P. dentatum Stein (Prorocentrales, Dinophyceae)

Abstract

In Japanese, Chinese and Korean coastal waters, recurrent blooms of a small, elongate Prorocentrum species have been observed in recent years. In previous studies, this species has been respectively identified as P. shikokuense, P. donghaiense and P. dentatum, despite morphological similarity and identical rDNA sequences. To resolve the confusion, morphological features, including the architectural details of the periflagellar area, were examined and ribosomal DNA (rDNA) sequences were obtained from specimens collected from the East China Sea and Korean coast, and a strain established in the waters off the Canary Islands of Spain. In addition, the descriptions of the three species and allied species were reviewed. Morphological observations and a phylogeny based on the SSU, ITS region and LSU rDNA sequences revealed that the previously confused species and our studied strains are conspecific and that the morphology of strains identified as P. dentatum in the phylogenetic trees does not coincide with P. dentatum sensu stricto. The confusion can be traced back to Dodge (1975, p. 116), who considered P. veloi, P. monacense and P. obtusidens as junior heterotypic synonyms of P. dentatum. However, Dodge's P. dentatum are closer to P. obtusidens sensu stricto, rather than P. dentatum sensu stricto. P. obtusidens sensu stricto can be distinguished from P. dentatum sensu stricto by its relatively small size, parallel sides towards the anterior and a blunt anterior extension on one side. This indicates that P. obtusidens should not be considered a synonym of P. dentatum sensu stricto. In addition, a comparison of the original descriptions of P. obtusidens and allied species allowed to conclude that small, elongate Prorocentrum from Japanese, Chinese and Korean coastal waters previously identified as P. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. shikokuense, P. donghaiense, P. dentatum sensu Yoo and Lee (1986) and the specimens studied herein, which share identical rDNA sequences, morphologically coincide with P. obtusidens. Therefore, it is proposed that P. shikokuense and P. donghaiense should be regarded as junior synonyms of P. obtusidens. Highlights ► Prorocentrum shikokuense Hada, P. donghaiense Lu and Prorocentrum obtusidens Schiller are conspecific. ► Prorocentrum obtusidens is a senior to P. shikokuense and P. donghaiense. ► Prorocentrum obtusidens is a separate species from P. dentatum sensu stricto, P. veloi and P. monacense. ► The periflagellar area of Prorocentrum obtusidens consists of seven platelets bearing a wing-like structure and two platelets without a wing-like structure, one flagellar pore and one accessory pore.

Metabarcoding Analysis of Harmful Algal Bloom Species in the Western Pacific Seamount Regions

“…Additionally, some ASVs each corresponded to multiple species in the Western Pacific seamount regions, suggesting that the 18S rDNA V4 region did not have adequate resolution for resolving phytoplankton species. For example, P. donghaiense, which is common in coastal waters in China, Japan, and Korea [65][66][67], was not identified (Figure 7f) because its 18S rDNA V4 sequence is identical to that of many other Prorocentrum species. Full-length 18S rDNA sequences may be needed to resolve these phytoplankton species.…”

The Notorious Harmful Algal Blooms-Forming Dinoflagellate Prorocentrum donghaiense Produces Sexual Resting Cysts, Which Widely Distribute Along the Coastal Marine Sediment of China

“…The two sequences of PCR products (Supplementary Appendix 1) exhibited 100% identity to a reference sequence of P. donghaiense deposited in NCBI database (Genbank accession No. KX656893), which was from Shin et al (2019a), demonstrating the presence of P. donghaiense in surface sediments most possibly as resting cyst, or, less likely, as other forms (e.g., vegetative cells or DNA residues).…”

“…However, there has been no study explaining the cosmopolitan distribution of this species. High cell density blooms of P. donghaiense have been reported from many countries (Hernández-Becerril et al, 2000;Ajani et al, 2011;Roselli et al, 2019;Shin et al, 2019a), and particularly in China (Lu et al, 2014). Since 2001, blooms of P. donghaiense have occurred annually in the similar area of the ECS (Lu D. et al, 2005;Lu et al, 2014).…”

“…It is noteworthy that although the species investigated in the present work has been recently proposed by Shin et al (2019a) to be named Prorocentrum obtusidens, we decided to keep the name P. donghaiense as described by Lu and Goebel (2001) because we firmly believe it is absolutely necessary to conduct a more detailed morpho-molecular examination for specimen from the type locality (the Adriatic Sea) of P. obtusidens before it can be accepted to replace P. donghaiense. Prorocentrum donghaiense is a globally distributed dinoflagellate that inhabits in estuarine and coastal waters of Asian countries (Lu and Goebel, 2001;Takano and Matsuoka, 2011;Lee et al, 2013;Lu et al, 2014;Shin et al, 2019a,b), Oceania countries (Chang, 1988;Ajani et al, 2011), European countries (Parke and Dixon, 1976;Viličić et al, 2002;Gómez, 2003;Gómez and Boicenco, 2004;Percopo et al, 2011;Guilloux et al, 2013), North and South American countries (Hernández-Becerril et al, 2000;Scorzetti et al, 2009;Muciño-Márquez et al, 2015;Rezende et al, 2015), and the Arctic areas (Okolodkov, 1998;Chang et al, 2013).…”

Spatial Distribution of Phytoplankton Community Composition and Their Correlations with Environmental Drivers in Taiwan Strait of Southeast China

“…In some cases, HABs can cause severe dissolved oxygen depletion, reduce light penetration, and increase phytotoxin concentrations, which have led to serious economic impacts on marine fisheries, the aquatic environment, and human health [2,3]. For example, from 18 May to 8 June 2012, a dinoflagellate bloom by the non-toxic Prorocentrum donghaiense was succeeded by a bloom of the toxic Karenia mikimotoi in coastal waters off north Fujian province (320 km 2 ), leading to an estimated loss of over 2 billion RMB (US$280 million) based on mortality of marine animals [4][5][6]. This illustrates that it is paramount to understand how physical and chemical environmental drivers govern bloom development and succession, which is necessary for prediction and prevention of algal blooms.…”