Cryptic speciation and hybridization in the toxic algal bloom-forming species complex Prymnesium parvum
Watervoort, N. (2026). Cryptic speciation and hybridization in the toxic algal bloom-forming species complex Prymnesium parvum. PhD Thesis. Purdue University: Indiana. 155 pp. https://dx.doi.org/10.25394/PGS.34063209
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Documenttype: Doctoraat/Thesis/Eindwerk
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| Trefwoord |
Prymnesium parvum N.Carter, 1937 [WoRMS]
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| Abstract |
Historically, the dominant way to determine species identity was with morphology. However, recent advancements in DNA sequencing have made it possible to genetically identify species. This frequently leads to clashes between morphological species concepts and genetic species concepts called cryptic species complexes, wherein one morphospecies may contain several genetically defined species. These cryptic species complexes are becoming more widely recognized and are particularly problematic in microbial eukaryotes. However, recognition of microbial cryptic species complexes in microbial eukaryotes lags behind their discovery. One microbial eukaryote cryptic species complex is the toxic haptophyte alga Prymnesium parvum sensu lato (s.l.). P. parvum s.l. is composed of at least three genetically distinct but morphologically identical species. Each species of P. parvum s.l. forms toxic algal blooms, produces different forms of the potent ichthyotoxin prymnesin, have different nucleotide content, and have different genome sizes. The P. parvum species complex was recently discovered, but failing to acknowledge its existence hinders experimental efforts and leads to significant confusion in the field. Here, I show that failing to account for different P. parvum s.l. cryptic species limits experimental success. I demonstrate different cryptic species of P. parvum s.l. can hybridize and generate unstable genomes. I also found that the genetic diversity of the P. parvum species complex is reflected in local populations and can be found in the same bloom. Taken together, P. parvum s.l. is a useful case study to demonstrate the importance of recognizing cryptic species diversity for experimental success and to fully delineate a species complex in microbial eukaryotes. |
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