Fungalpedia – Note 2806, Arthrodermataceae
Arthrodermataceae. Locq. ex Currah.
Citation when using this data: Kandemir H et al. 2022 – Fungalpedia.
Index Fungorum, Facesoffungi, MycoBank, GenBank
Classification: Onygenales, Eurotiomycetidae, Eurotiomycetes, Pezizomycotina, Ascomycota, Fungi
Ancestral members of this family generally have white, pale yellow or yellowish-brown, globose ascomata with appendages; thin-walled, transparent, subglobose to globose asci; hyaline to pale yellow, smooth, minute, oblate to oblate-discoid or oblate-convex ascospores (Currah 1985). They often produce large, multiseptate macroconidia in addition to one-celled, sessile microconidia of the chrysosporium-like (except genus Ctenomyces) (Currah 1985). In the derived, mostly human-associated species (i.e., Trichophyton rubrum), sexuality tends to be lost (Persinoti et al. 2018), and as in the case of T. tonsurans and T. equinum, species might evolve as separate clones with a specific mating-type (Gräser et al. 2006; Kano et al. 2014; Kandemir et al. 2020). The family comprises the genera Arthroderma, Ctenomyces, Epidermophyton, Guarromyces, Keratinophyton, Lophophyton, Microsporum, Nannizzia, Paraphyton and Trichophyton (de Hoog et al. 2017). Phylogenetic results showed that type strains of several described Chrysosporium species and that of Pectinotrichum chinense (ex-type culture LC5811) clustered in the family among species of Arthroderma . Additionally, Shanorella spirotricha (ex-type culture CBS 305.56) and Leucothecium emdenii (ex-type culture CBS 576.73) were found to be close to Arthrodermataceae. Available molecular and morphological data for the last two species were combined, and they are judged as incertae sedis.
Members of Arthrodermataceae are characteristically mammal-associated fungi with keratinolytic abilities. Otčenášek and Dvořák (1975) classified them as geophilic, zoophilic and anthropophilic, depending on the part of the life cycle that is environmental or closer to the mammalian or human host. De Hoog et al. (2018) used transmissibility as a criterion to distinguish environmental pathogens from zoophilic pathogens, with infection taking place either via environmental propagules or by direct host-to-host transmission. However, determination of the natural habitat of a species may not always be easy. Geophilic, zoophilic and anthropophilic occurrences are statistical trends rather than diagnostic parameters. These ecological trends are also approximately reflected in sexuality, clonality and loss of specialized reproduction (de Hoog et al. 2017; Persinoti et al. 2018). Anthropophilic species are necessarily at the top of phylogenetic trees, given that Homo sapiens is the most recent host (Gräser et al. 2000). Transmission occurs by skin flakes loaded with amorphous fungal cells, associated with significant morphological reduction compared to the elaborate environmental sexual forms commonly observed in geophiles (Li et al. 2010). Zoophilic species lie between these two edges by mostly sporulating and showing sexual reproduction upon mating (Metin and Heitman 2017). Changes in habitat and host preference at the species level are usually accompanied by slight differences in phenotypic and physiological characteristics (Kandemir et al. 2020; Su et al. 2019).
Since dermatophytes are among the well-studied groups in the order Onygenales in terms of laboratory identification, antifungal resistance and taxonomy (de Hoog et al. 2017; Dukik et al. 2017; Gupta et al. 2017; L’Ollivier and Ranque 2017; Martinez-Rossi et al. 2018; Khurana et al. 2019; Monod 2019; Su et al. 2019; Baert et al. 2020; Čmoková et al. 2020), we summarize currently available data for the remaining family members below.
During phylogenetic analyses, several GenBank records were encountered with other generic names than the ones above but clustered in Arthrodermataceae. Two strains were deposited as Onygena corvina CBS 225.60 and CBS 281.48 (LSU MH869510 and FJ358287, respectively) and were misidentified. Both strains showed 100% LSU identity with Arthroderma crocatum, type strain IHEM 5251, KT155108 (Hainsworth et al. 2021). This was confirmed by CBS 225.60 having 99.6% ITS identity with A. crocatum CBS 130.70 (AJ877223) in the present study.
Corda (1833) introduced the genus Chrysosporium, with Chrysosporium corii as a type species. The original leather material, dating back to 1833 from herbarium in Prague (PR), Czech Republic, is preserved at the Canadian National Mycological Herbarium with a slide of the type DAOM 55541 (personal communication with Jennifer Wilkinson). To stabilize the current nomenclature, van Oorschot (1980) proposed C. merdarium as a type species of the genus, using slide DAOM 43321 as a reference. However, this material is not interpretable either, and the status of the species remains uncertain. Numerous species have been described in Chrysosporium based on morphology, which according to modern criteria, are nondiagnostic. The described Chrysosporium species appear highly polyphyletic, i.e., C. longispora (current name Paranannizziopsis longispora) in Onygenales (Sigler et al. 2013), C. pilosum (current name Arachnomyces pilosus) in Arachnomycetales (Sun et al. 2019), C. verrucosum (current name Pseudogymnoascus pannorum is in Thelebolales (Minnis and Lindler 2013), C. xerophilum (current name Xerochrysium xerophilum) is in Eurotiales (Pitt et al. 2013) and C. thermophilum (current name Thermothelomyces thermophilusis) in Sordariales (Marin-Felix et al. 2015). Given this polyphyly and the fact that no interpretable type material exists, we regard Chrysosporium as nomen confusum.
The ex-type strain of Chrysosporium kuzurovianum, CBS 667.78, has been recorded as a synonym (van Oorschot 1980) of C. keratinophilum (ex-type culture CBS 104.62). However, it differs by its colony color, larger conidia, the presence of multiple conidial shapes and the absence of arthroconidia (Scharapov 1974; van Oorschot 1980). This is confirmed by phylogeny showing affinity to Arthroderma multifidum (99.7% LSU to KT155237, 97% ITS to KT155892).
Type genus: Arthroderma Curr.—Outl. Brit. Fung. (London): 357, 1860.
Other accepted species: Species Fungorum – search Arthrodermataceae.
References
Corda ACJ 1833 – Icones Fungorum hucusque cognitorum. Prague: J.G. Calve.
L’Ollivier C, Ranque S 2017 – Dermatophytes in the tropics. Rev Iberoam Micol 34:59–66.
Metin B, Heitman J 2017 – Sexual reproduction in dermatophytes. Mycopathologia 182(1–2):45–55.
Minnis AM, Lindner DL 2013 – Phylogenetic revision of Pseudogymnoascus. Fungal Diversity 58:269–280.
Monod M 2019 – Secreted proteases from dermatophytes. Mycopathologia 184:155–168.
Otčenášek M, Dvořák J 1975 – Ecological classification of dermatophytes. Mycoses 18(10):425–434.
Scharapov VI 1974 – New species of Chrysosporium. Mycologia 66:123–130.
van Oorschot CAN 1980 – A revision of Chrysosporium and allied genera. Stud Mycol 20:1–89.
Entry by
Hazal Kandemir, Center of Expertise in Mycology, Radboud University Medical Center/Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Division of Medical Mycology, Faculty of Medicine, University of Cukurova, Adana, Turkey
Published online