Antiquispora Magurno, Uszok, Esmaeilzadeh-Salestani, Tedersoo, M. B. Queiroz & B. T. Goto, 2025

Esmaeilzadeh-Salestani, Keyvan, Queiroz, Mariana Bessa de, Mikryukov, Vladimir, Uszok, Sylwia, Goto, Bruno Tomio, Tedersoo, Leho & Magurno, Franco, 2025, Morphological and phylogenetic analysis of the early-diverging lineage of Glomeromycota suggest two new genera and recombinations in Archaeosporales, MycoKeys 124, pp. 249-273 : 249-273

Antiquispora Magurno, Uszok, Esmaeilzadeh-Salestani, Tedersoo, M. B. Queiroz & B. T. Goto gen. nov.

Fig. 5 A – I

Etymology.

Latin, antiquus (= ancient) and spora (= spores), referring to the phylogenetic placement of this genus within Archaeosporales , an early-diverging lineage of Glomeromycota.

Type species.

Antiquispora disseminans Magurno, Uszok, M. B. Queiroz & B. T. Goto .

Diagnosis.

Differs from Archaeospora and other genera of Archaeosporaceae in (i) having two hyaline spore walls and four layers, (ii) intraradical hyphae, spores, and vesicles stain darkly in trypan blue, and (iii) in the nucleotide composition of sequences of the partial SSU-ITS-LSU nrDNA region (see Discussion for details).

Genus description.

Spores acaulosporoid, formed singly in the substrate or occasionally within roots. Spores hyaline to white, small (55–67 µm diam), globose to subglobose, rarely ellipsoid to ovoid. Subcellular spore structure composed of two walls: the outer wall with two hyaline layers, and the inner wall with two permanent, flexible to semi-flexible layers. None of the layers in either wall stain with Melzer’s reagent. Sporiferous saccule hyaline to subhyaline, with a delicate mono- to bi-layered wall continuous with the two outer spore wall layers; usually collapsed or detached in extraradical spores. Spore walls and saccule wall staining dark in Trypan blue. Forming mycorrhizal structures staining dark in Trypan blue.

Ecology and distribution.

Environmental sequencing data indicate that the genus has a broad geographical and ecological distribution, having been recorded in tropical, subtropical, temperate, and even subpolar regions, across approximately 60 countries in the Americas, Africa, Asia, Europe, and Oceania (Suppl. material 4). It occurs in a broad range of natural and human-modified habitats, including various types of forests, shrublands, grasslands, woodlands, deserts, tundra, freshwater environments, and anthropogenic landscapes such as croplands, rangelands, villages, and urban areas (Suppl. material 5).

Figures

Figure 5. Antiquispora disseminans. A. Intact spores with dense, oily cytoplasmic content forming irregular droplets. B – F. Spores with two distinct walls (sw, iw), each composed of two layers: swl 1–2 and iwl 1–2; G. Spores and intraradical hyphae; H. Spore (sp) formed laterally on the neck of a sporiferous saccule (sac), with a detail of the scar at the spore base; I. Spores showing wall structure with four layers and detail of the germ shield (gs); C. Spores in PVLG. A, B, D – F. Spores in PVLG + Melzer’s reagent; G – I. Spores and other structures stained in 0.1 % Trypan blue. Scale bars: 25 μm (A, G, H); 10 μm (B – F, I).