Myrmecridium hydei Asghari, Phukhams. & E. B. G. Jones 2023, sp. nov.
Creators: name: Asghari, Raheleh
name: Phukhamsakda, Chayanard
name: Karimi, Omid
name: Apurillo, Carlo Chris S.
name: Jones, E. B. Gareth
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Sordariomycetes
Myrmecridiales
Myrmecridiaceae
Myrmecridium
Myrmecridium hydei

description: Myrmecridium hydei Asghari, Phukhams. & E.B.G. Jones sp. nov.   
 Index Fungorum number: IF 901177, Facesoffungi number: FoF 14964   
 Etymology:— Named in honor of Prof. Kevin D. Hyde for his excellent contribution to mycology.   
 Holotype:— MFLU 23-0364   
 Saprobic on decaying branch of Areca species. Sexual morph: Undetermined. Asexual morph: Hyphomycetous (in vivo, Fig. 2). Colonies on natural substrate hairy, black, with white conidial masses. Conidiophores 115–250 × 2.5–4 µm (x̄ = 185 × 3 μm, n = 15), solitary or in small groups, macronematous, mononematous, straight or flexuous, unbranched, thick-walled, pale brown, gradually becoming paler towards the apex, later turning dark brown at base and brown toward apex with slightly thickened scars, septate. Conidiogenous cells 50–205 × 1.5–2.5 µm (x̄ = 123 × 2.2 μm, n = 15) with scattered, pimple-shaped denticles bearing conidia. Conidia 4.3−6.5 × 2.5−3.5 µm (x̄ = 5 × 3 μm, n = 25), solitary, ellipsoidal to obovoid to subglobose in mature conidia, with protuberant unpigmented hilum, thick-walled, smooth or finely verrucose to granular, subhyaline, aseptate, without wing-like sheath. Hyphomycetous (in vitro, Fig. 3). Colonies on PDA. Submerged hyphae 0.6–2 µm wide (x̄ = 1.5 μm, n = 15), hyaline, thin-walled. Aerial hyphae hyaline to medium brown, septate. Conidiophores 35–275 × 2–4 µm (x̄ = 170 × 3 μm, n = 15), unbranched, straight or flexuous to geniculate-sinuous, sympodial, arising from creeping aerial hyphae, pale brown to medium brown, paler at the apex, thick-walled, smooth, with up to 20 septa, sometimes constricted at septa, basal cell often inflated, 3–7 μm wide (x̄ = 4.5 μm, n = 15). Conidiogenous cells 30–210 × 2–3 µm (x̄ = 133 × 2.5 μm, n = 15), integrated, elongating sympodial, cylindrical, flexuous, polyblastic, pale brown to medium brown at the base, subhyaline in the upper part, septate, thick-walled near the base, thin-walled toward the apex, with scattered pimple-shaped, unpigmented denticles 0.5–1.2 × 0.5–1 µm (x̄ = 0.7 × 0.7 μm, n = 25). Conidia 3–8 × 2–4.5 µm (x̄ = 6 × 3.5 μm, n = 35), solitary, ellipsoid to obovoid to irregular, subhyaline, thick-walled, finely verrucose, containing two large guttules without wing like sheath, with one hilum. Hilum 0.5–1 μm wide (x̄ = 0.7 μm, n = 15), prominent, unpigmented.   
 Culture characteristics:— Conidia germinating on PDA within 24 hours. Colonies on PDA and MEA reaching up to 2 cm diameter after 2 weeks and 5 cm after 4 months at 24 °C. Mycelium submerged at the edge, flat, white to pale yellow, later becoming powdery to velvety and greyish light brown due to sporulation, with fertile bundles of hyphae and entire margin; reverse yellow with orange at the center.   
 Material examined:— THAILAND. Prachuap Khiri Khan Province: Pranburi,on decaying Areca wood submerged in seawater, 25 October 2022, K.D. Hyde, R6B (MFLU 23-0364, holotype); ex - type living culture MFLUCC 23-0217, additional living culture MFLUCC 23-0218.   
 GenBank numbers:— MFLUCC 23-0217 (ex - type): ITS = OR500543, LSU = OR500545, rpb2 = OR515019, tef1-α = OR515020; MFLUCC 23-0218: ITS = OR500544, LSU = OR500546.   
 Notes:— The reconstruction of phylogenies from ITS and LSU sequences showed that Myrmecridium hydei formed a distinct clade with M. phragmitigenum, M. phragmiticola and M. sambuci in both maximum likelihood and Bayesian analyses with 80 SH-aLRT/77 UFB/0.83 BPP statistical support. In a BLAST search in GenBank, the closest match of the ITS sequence of M. hydei (MFLUCC 23-0217) was 99.63% similar across 99% of the query sequence to M. schulzeri (NTOU 4421), which translates into 98.63% similarity. In a BLAST search in GenBank, the closest match of the LSU sequence of M. hydei (MFLUCC 23-0217) was 100% similar across 98% of the query sequence to M. schulzeri (CBS 188.96), which translates into 98% similarity. Myrmecridium hydei differs from M. schulzeri in having flexuous conidiophores and lacking a wing-like sheath to the conidia (Arzanlou et al. 2007). Myrmecridium hydei (MFLUCC 23-0217) has similar characters to M. flexuosum, but M. flexuosum is distinguishable by having shorter conidiophores without strongly constricted, shorter pimple-like denticles, and it has conidia with a sheath (Arzanlou et al. 2007). Therefore, Myrmecridium hydei is introduced as a novel species based on its distinct morphology and phylogenetic evidence.
description: Published as part of Asghari, Raheleh, Phukhamsakda, Chayanard, Karimi, Omid, Apurillo, Carlo Chris S. & Jones, E. B. Gareth, 2023, Myrmecridium hydei, a novel marine species from Thailand, pp. 265-279 in Phytotaxa 625 (3) on page 269, DOI: 10.11646/phytotaxa.625.3.3, http://zenodo.org/record/10150632