Fungalpedia – Note 2626, Echinothecium
Echinothecium Zopf.
Citation when using this data: Meng QF et al. – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Dothideomycetes genera incertae sedis, Pezizomycotina, Ascomycota, Fungi
The lichenicolous genus Echinothecium was established by Zopf (1898) to accommodate the type species E. reticulatum Zopf. This genus is characterized by a superficial thallus, globose, ostiolate ascomata with stiff, simple appendages, 8-spored asci, and hyaline, oval, asymmetric ascospores with two cells (Chomnunti et al. 2011).
Eriksson et al. (1993) placed Echinothecium in Capnodiaceae due to its superficial ascomata with free hyphoid appendages and colorless spores. However, Roux et al. (1994b) compared the hamathecium of Sphaerellothecium and Echinothecium and argued that the presence of free ascomatal appendages in Echinothecium is not a definitive distinguishing feature, as similar appendages are found in some species of Sphaerellothecium and Stigmidium. Furthermore, they noted that the absence of interascal filaments in Echinothecium cannot serve as a genus-level character since these filaments are often not visible in saprophytic Sphaerellothecium.
Calatayud et al. (2002) misidentified Lichenostigma cosmopolites Hafellner & Calat., confusing it with Echinothecium reticulatum. This misidentification was based on the presence of ascomata with septate, seta-like hyphae, which appear to be restricted to Parmelia. Etayo (2008) later transferred E. reticulatum to Sphaerellothecium, a move supported by Chomnunti et al. (2011) after examining the holotype of Sphaerellothecium. As a result, Echinothecium reticulatum was synonymized with Sphaerellothecium reticulatum, and the genus was transferred to Mycosphaerellaceae. Roux (2021) introduced a new species, Echinothecium rhizoplacae, and discussed five additional species within the genus. In this study, Roux demonstrated that the hamathecium of E. rhizoplacae and E. reticulatum differs significantly from Sphaerellothecium due to the presence of short rudimentary pseudoparaphyses and the absence of paraphysoids. These distinctive features, along with the presence of ascomata with free hyphoid appendages, reinforce the validity of Echinothecium as a separate genus (Roux 2021).
Although several scholars have proposed placements for Echinothecium based on morphological characteristics, its phylogenetic position remains uncertain due to the lack of molecular data. Hyde et al. (2024) placed this genus within Dothideomycetes as genera incertae sedis. Based on this evidence, we accept this classification and retain Echinothecium glabrum and E. reticulatum within Echinothecium, with E. reticulatum as the type species.
Type species: Echinothecium reticulatum Zopf.
Other accepted species: Species Fungorum – search Echinothecium.
Figure 1 – Echinothecium reticulatum redrawn from Chomnunti et al. (2011). a Ascomata on Parmelia sulcata. b Ascomata. c Bitunicate asci. d Ascospores. Scale bars: b = 20 μm, c = 10 μm, d = 5 μm.
References
Eriksson O, Hawksworth DL. 1993 – Outline of the Ascomycetes – 1993. Systema Ascomycetum 12 (1–2), 51–207.
Entry by
Meng QF, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand and School of Public Health, Zunyi Medical University, Guizhou 563000, China.
Published online 23 June 2026