Arcyria chinggiskhanii A. Vlasenko & V. Vlasenko, 2024

Vlasenko, Anastasia V., Enkhtuya, Ochirbat, Degidmaa, Turmunkh, Enkhjargal, Enkhtaivan, Chelobanov, Boris P. & Vlasenko, Vyacheslav A., 2024, Three new species of bright-spored myxomycetes from Asia and the second world record of Perichaena maculosa, Phytotaxa 663 (4), pp. 205-220 : 208-211

Arcyria chinggiskhanii A. Vlasenko & V. Vlasenko sp. nov. ( Figs. 1 , 2 ).

MycoBank no: 855057

Etymology:— Named after Genghis Khan (Chinggis Khan), founder and first khan of the Mongol Empire.

Sporangia on stalks, individual or in small groups, ovoid, 1.0– 1.4 mm tall, 0.3–0.5 mm diam., grey-ochre, greyyellow, with a bluish tint due to the preservation of individual parts of the peridium on the sporotheca, not increasing in size after maturity. Calyculus ocher, shiny, well developed, cup-shaped, folded, membrane-like. In SEM, the inner surface of the calyculus is ornamented with semi-ring-shaped lines forming a network with round cells. Stalk black, dark grey-green, thick, widening towards the bottom, well developed, length equal to or exceeds height of the sporotheca, with spore-like cells. Hypothallus clearly visible, membranous, yellow, individual for each sporangium. Capillitium well developed and tightly attached to entire inner surface of the calyculus. Threads of capillitium 3–5.5 µm diam., with a small number of free rounded ends, ornamented with warts. In SEM, threads of capillitium ornamented with large warts that merge into lines and form ridges , between which there is a mesh ornamentation with perforations. Spores sand-colored in mass, yellowish in transmitted light, spherical, thick-walled, 9–8 µm diam., ornamented with warts. In SEM, spores ornamented with coral-like warts in groups of different sizes. Plasmodium unknown.

Holotype:— MONGOLIA. Khentii Mountains, Bogd-Khan-Uul Mountain, Bogd Khan Uul Biosphere Reserve , dark coniferous forest, living on bark of Lonicera sp. , 47°45’52.61” N, 107° 0’8.74” E, 1835 m a.s.l., field substrate sample coll. 1 October 2019, V. A. Vlasenko, moist chamber culture 6 February 2020, cult. and ident. A. V. Vlasenko, NSK 1031205 , GenBank No.: PQ032484.

Additional specimen examined:— MONGOLIA. Bogd-Khan-Uul Mountains, Bogd Khan Uul Biosphere Reserve, dark coniferous forest, on bark of Lonicera sp. , 47°46’08” N, 106°59’18” E, 1850 m a.s.l., field substrate sample coll. 24 July 2023, A. V. Vlasenko, moist chamber culture 14 May 2024, cult. and ident. A. V. Vlasenko, NSK 1031216.

Eсology:— Grows on bark of Lonicera .

Comments:— The sporangia of Arcyria chinggiskhanii resemble those of A. annulifera G. Lister & Torrend , A. cinerea (Bull.) Pers. , A. nigella Emoto , A. riparia L.G. Kreiglst , A. verrucosituba Nann. -Bremek. & Schinner in shape and colour, but the presence of the remains of a shiny bluish peridium on the sporotheca and the ornamentation of the spores allows us to clearly distinguish the new species from those listed above. Spores of A. chinggiskhanii are ornamented with coral-like warts, located in groups of different size. Similar ornamentation in the genus Arcyria is also seen in A. leiocarpa (Cooke) Massee. However , the ornamentation of the threads of capillitium in A. chinggiskhanii and A. leiocarpa differs greatly. Those of A. leiocarpa have 3–5 spiral thickenings, mostly smooth, but in places where the spiral ornamentation is not sufficiently expressed, small spines are present. Spiral thickenings on the threads of capillitium are absent in A. chinggiskhanii but rather there is an original ornamentation in the form of large warts that merge into lines and form ridges , between which there is a mesh ornamentation with perforation. A similar type of ornamentation of the threads of capillitium with mesh perforation is noted, for example, in Perichaena calongei Lado, D. Wrigley & Estrada.

The ML analysis based on the 18S nrDNA region ( Fig. 3 ) showed that the new species Arcyria chinggiskhanii is an independent species, closest to A. cinerea . The genetic distance of the A. chinggiskhanii branch on the SSU tree is 0.059, with 97% bootstrap support.

Figures

FIGURE 1. Arcyria chinggiskhanii (holotype). A. Sporangia (RL). B. Stem and calyculus (RL). C. Sporangia; arrows show remains of peridium on the sporotheca (RL). D. Threads of capillitium (TL). Scale bars:A = 0.5 mm, B = 0.3 mm, C = 0.5 mm, D = 20 µm.

FIGURE 2. Arcyria chinggiskhanii (holotype). A–B. Sporangium (SEM). C. Calyculus (SEM). D. Remnants of peridium on surface of the sporotheca (SEM). E. Ornamentation on inner surface of the calyculus (SEM). F–G. Thread of capillitium (SEM). H–I. Spore (SEM). Scale bars:A = 200 µm, B = 200 µm, C = 100 µm, D = 4 µm, E = 2 µm, F = 2 µm, G = 1 µm, H = 2 µm, I = 2 µm.

FIGURE 3. Maximumlikelihood tree basedon18SnrDNAsequences shows the phylogeneticrelationships betweenArcyria chinggiskhanii and closely related species of the genus Arcyria. BS values with high support and Bayesian posterior probabilities are shown in the branches. GenBank accession numbers are given after the species name.