Fungalpedia –Note 18 Hondaea

Hondaea A. Amato & O. Cagnac

Index Fungorum number: IF 92274; Fig. 1

Thraustochytrids as marine protists are highly ecologically relevant to mangrove environments (Raghukumar et al. 1994, Burki et al. 2014). Dellero et al. (2018) collected two thraustochytrid strains from mangroves in Mayotte island (Indian Ocean), one of which was proposed as a new genus Hondaea based on morphological, phylogenetic, genomic and lipidomic analyses. Hondaea is a mono-specific genus with Hondaea fermentalgiana as the type species (Dellero et al. 2018). There are no further reports of Hondaea species in Species Fungorum (2023). Hondaea is characterized by spherical or subspherical, uninuclear or multinuclear vegetative cells, and the absence of ectoplasmic nets and amoeboid cells. Heterokaryotic zoospores are released by zoosporangia, produced by multinucleated cell division. Additionally, this genus produces high levels of pentadecanoic acid and n−3 docosapentaenoic acid, and pigments dominated by β-carotene, canthaxanthin and astaxanthin. Sterols are abundant in cholesterol, lathosterol and stigmasterol (Dellero et al. 2018). It also contains a small amount of squalene. Phylogenetic studies based on 18S rDNA showed Hondaea formed a sister clade with Aurantiochytrium, but it differs from the latter by its smaller zoospores and missing amoeboid cells (Dellero et al. 2018). Notably, Dellero et al. (2018) established this genus without showing a recognized repository to deposit the types in the protologue. Therefore, based on the International Code of Nomenclature for algae, fungi, and plants, specifically the Art. F.5.1 in Shenzhen Code (Turland et al. 2018), Hondaea is an invalid name and thus needs validating.

Type species: Hondaea fermentalgiana A. Amato & O. Cagnac

Fig. 1. Hondaea fermentalgiana (CCAP 4062/3). a. Vegetative cells. b. Mononucleate cells. c. Zoosporangium. d. Zoospore. Scale bars: a = 20 μm. b, c = 10 μm. d = 5 μm. Redrawn from Dellero et al. (2018).


Burki F 2014 – The eukaryotic tree of life from a global phylogenomic perspective. Cold Spring Harbor perspectives in biology 6: a016147.

Dellero Y, Cagnac O, Rose S, Seddiki K, Cussac M, Morabito C, Lupette J, Cigliano RA, Sanseverino W, Kuntz M, Jouhet J, Maréchal E, Rébeillé F, Amato A 2018 – Proposal of a new thraustochytrid genus Hondaea gen. nov. and comparison of its lipid dynamics with the closely related pseudo-cryptic genus Aurantiochytrium. Algal Research 35: 125–141.

Raghukumar S, Sharma S, Raghukumar C, Sathe-Pathak V, Chandramohan D 1994 –Thraustochytrid and fungal component of marine detritus. IV. Laboratory studies on decomposition of leaves of the mangrove Rhizophora apiculate Blume. Journal of experimental marine biology and ecology 183: 113–131.

Turland NJ, Wiersema JH, Barrie FR, Greuter W, Hawksworth DL, Herendeen PS, Knapp S, Kusber WH, Li DZ, Marhold K, et al. (eds.). International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile 159. Glashütten: Koeltz Botanical Books, 2018.

Entry by

Ming Zeng

1School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand

2Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand

3Yunnan Key Laboratory of Fungal Diversity and Green Development, Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China

(Edited by Chitrabhanu S. Bhunjun and Kevin D. Hyde)