In response to a comment in this issue on our proposal of new terminology to distinguish red algal parasites, we clarify a few key issues. The terms adelphoparasite and alloparasite were previously used to identify parasites that infected close or distant relatives. However, most red algal parasites have only been studied morphologically, and molecular tools have shown that these binary terms do a poor job at representing the range of parasite-host relationships. We recognize the need to clarify inferred misconceptions that appear to be drawing from historical terminology to contaminate our new definitions. We did not intend to replace the term adelphoparasite with neoplastic parasites and the term alloparasites with archaeplastic parasites. Rather, we seek to establish new terms for discussing red algal parasites, based on the retention of a native plastid, a binary biological trait that is relatively easy to identify using modern methods and has biological implications for the interactions between a parasite and its host. The new terminology can better account for the spectrum of relationships and developmental patterns found among the many independently evolved red algal parasites, and it is intended to inspire new research, particularly the role of plastids in the survival and evolution of red algal parasites.

Department of Biological Sciences University of Rhode Island Kingston Rhode Island USA

Institute of Parasitology Biology Centre of the Czech Academy of Sciences České Budějovice 370 05 Czech Republic

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Blouin, N. A. & Lane, C. E. 2012. Red algal parasites: Models for a life history evolution that leaves photosynthesis behind again and again. BioEssays 34:226-35.

Freese, J. M. & Lane, C. E. 2017. Parasitism finds many solutions to the same problems in red algae (Florideophyceae, Rhodophyta). Mol. Biochem. Parasitol. 214:105-11.

Goff, L. J. & Coleman, A. W. 1995. Fate of parasite and host organelle DNA during cellular transformation of red algae by their parasites. Plant Cell. 7:1899-911.

Kurihara, A., Abe, T., Tani, M. & Sherwood, A. R. 2010. Molecular phylogeny and evolution of red algal parasites: a case study of Benzaitenia, Janczewskia, and Ululania (Ceramiales). J. Phycol. 46:580-90.

Preuss, M., Nelson, W. A. & Zuccarello, G. C. 2017. Red algal parasites: a synopsis of described species, their hosts, distinguishing characters and areas for continued research. Bot. Mar. 60:13-25. https://doi.org/10.1515/bot-2016-0044

Preuss, M. & Zuccarello, G. C. 2018. Three new red algal parasites from New Zealand: Cladhymenia oblongifoliaphila sp. nov. (Rhodomelaceae), Phycodrys novae-zelandiaephila sp. nov. (Delesseriaceae) and Judithia parasitica sp. nov. (Kallymeniaceae). Phycologia 57:9-19.

Preuss, M. & Zuccarello, G.C. 2020. A comment on Salomaki and Lane 2019 “Molecular phylogenetics supports a clade of red algal parasites retaining native plastids: taxonomy and terminology revised.” J. Phycol.. This issue.

Salomaki, E. D. & Kolisko, M. 2019. There is treasure everywhere: Reductive plastid evolution in Apicomplexa in light of their close relatives. Biomolecules 9:378.

Salomaki, E. D. & Lane, C. E. 2014. Are all red algal parasites cut from the same cloth? Acta Soc. Bot. Pol. 83:369-75.

Salomaki, E. D. & Lane, C. E. 2019. Molecular phylogenetics supports a clade of red algal parasites retaining native plastids: taxonomy and terminology revised. J. Phycol. 55:279-88.

Salomaki, E. D., Nickles, K. R. & Lane, C. E. 2015. The ghost plastid of Choreocolax polysiphoniae. J. Phycol. 51:217-21.

Sherwood, A. R., Kurihara, A., Conklin, K. Y., Sauvage, T. & Presting, G. G. 2010. The Hawaiian Rhodophyta Biodiversity Survey (2006-2010): a summary of principal findings. BMC Plant Biol. 10:258.

Wicke, S. & Naumann, J. 2018. Molecular evolution of plastid genomes in parasitic flowering plants. Adv. Bot. Res. 85:315-47.

Yang, E. C., Boo, S. M., Bhattacharya, D., Saunders, G. W., Knoll, A. H., Fredericq, S., Graf, L. & Yoon, H. S. 2016. Divergence time estimates and the evolution of major lineages in the florideophyte red algae. Sci. Rep. 6:21361.

Yang, M. Y. & Kim, M. S. 2015. Taxonomy of Grateloupia (Halymeniales, Rhodophyta) by DNA barcode marker analysis and a description of Pachymeniopsis volvita sp. nov. J. Appl. Phycol. 27:1373-84.

Zhu, G., Marchewka, M. J. & Keithly, J. S. 2000. Cryptosporidium parvum appears to lack a plastid genome. Microbiology 146:315-21.

Zuccarello, G. C., Moon, D. & Goff, L. J. 2004. A phylogenetic study of parasitic genera placed in the family Choreocolacaceae (Rhodophyta). J. Phycol. 40:937-45.