Fungalpedia – Note 448, Extremus

 

Extremus Quaedvl. & Crous 

Citation when using this data: Tibpromma et al. 2024 (in prep.) – Fungalpedia, Rock-inhabiting fungi.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1 

Classification: Extremaceae, Mycosphaerellales, Dothideomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi.

Based on DNA sequence and morphological analyses, Quaedvlieg et al. (2014) erected Extremus within Extremaceae, Mycosphaerellales, in Dothideomycetes with the type species E. adstrictus. The type species was initially described as Devriesia adstricta by Egidi et al. (2014). Later, this genus was an invalid deal to be published as a combination but ‘basionym’ (Nom. inval., Art. 40.1, see Arts 40.3 and Arts 6.3, 12.1 (Melbourne)). In 2019, this genus was validated on the basis of its morphology and DNA sequences (Crous et al. 2019). Currently, three taxa are included within Extremus viz: E. adstrictus from rocks in Spain, E. antarcticus from rocks in Antarctica, and E. caricis from dead leaves of Carex sp. in Netherlands (Quaedvlieg et al. 2014, Crous et al. 2023). Moreover, E. adstrictus and E. antarcticus only found their asexual morph, E. caricis only found sexual morph (Quaedvlieg et al. 2014, Crous et al. 2023). The asexual morph is characterized by sub-cylindrical to ellipsoid, brown conidiogenous cells, catenate, and sub-cylindrical to ellipsoid conidia hila (Quaedvlieg et al. 2014). The sexual features are characterized by separate, globose, brown ascomata with central ostiole, subcylindrical to obovoid, stipitate asci with apical chamber, straight, hyaline, smooth, medianly 1-septate, fusoid-ellipsoid ascospores (Crous et al. 2023).

Type species: Extremus adstrictus Quaedvl. & Crous

Other accepted species: Species Fungorum – search Extremus

 

 

Figure 1 – Extremus adstrictus (CBS 136103 = CCFEE 451, holotype). a Conidia with a dark median septum. b Meristematic growth (arrow indicated longitudinal and transversal septa are formed leading to meristematic development). Scale bars: a, b = 10 μm. Redrawn from Egidi et al. (2014).

 

References 

Crous PW, Costa MM, Kandemir H, Vermaas M et al. 2023 – Fungal Planet description sheets: 1550–1613. Persoonia-Molecular Phylogeny and Evolution of Fungi 51(1), 280–417.

Crous PW, Schumacher RK, Akulov A, Thangavel R et al. 2019 – New and interesting fungi. 2. Fungal Systematics and Evolution 3, 57.

Egidi E, De Hoog GS, Isola D, Onofri S et al. 2014 – Phylogeny and taxonomy ofmeristematic rock-inhabiting black fungi in the Dothideomycetes based on multi-locus phylogenies. Fungal Diversity 65, 127–165.

Quaedvlieg W, Binder M, Groenewald JZ, Summerell BA et al. 2014. – Introducing the Consolidated Species Concept to resolve species in the Teratosphaeriaceae. Persoonia 33, 1–40.

 

Entry by

Han L-S, Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, Yunnan 655011, P.R. China.

 

(Edited by Saowaluck Tibpromma, Samaneh Chaharmiri-Dokhaharani, & Achala R. Rathnayaka)

 

Published online 2 December 2024

Back to Glossary Index Page