Akanthomyces bashanensis W.H. Chen, Y.F. Han & J.D. Liang, 2023

Chen, Wan-Hao, Liang, Jian-Dong, Ren, Xiu-Xiu, Zhao, Jie-Hong & Han, Yan-Feng, 2023, Study on species diversity of Akanthomyces (Cordycipitaceae, Hypocreales) in the Jinyun Mountains, Chongqing, China, MycoKeys 98, pp. 299-315 : 299

Akanthomyces bashanensis W.H. Chen, Y.F. Han & J.D. Liang sp. nov.

Fig. 3

Type.

China, Chongqing, Beibei District, Jinyun Mountain (29°50'22.14959"N, 106°23'18.0744"E). On a dead spider ( Araneae ), 1 May 2021, Wanhao Chen, GZAC CQ0562 (holotype), ex-type living culture, CQ05621 .

Description.

Spider host completely covered by white mycelium. Conidiophores mononematous, arising from the lateral hyphae. Colonies on PDA, attaining a diameter of 26-27 mm after 14 days at 25 °C, white, consisting of a basal felt, floccose hyphal overgrowth; reverse yellowish. Hyphae septate, hyaline, smooth-walled, 1.5-1.9 μm wide. Conidiophores mononematous, hyaline, smooth-walled, with single phialide or whorls of 2-4 phialides or verticillium-like from hyphae directly, 12.1-20.5 × 1.5-2.1 μm. Phialides consisting of a cylindrical, somewhat inflated base, 11.8-12.9 × 1.3-1.6 μm, tapering to a thin neck. Conidia hyaline, smooth-walled, fusiform to ellipsoidal, 1.7-2.6 × 1.6-1.8 μm, forming divergent and basipetal chains. Sexual state not observed.

Etymology.

Referring to its location in Jinyun Mountain, which was formerly known as Bashan.

Additional strain examined.

China, Chongqing, Beibei District, Jinyun Mountain (29°50'22.14959"N, 106°23'18.0744"E). On a dead spider ( Araneae ), 1 May 2021, Wanhao Chen, CQ05622.

Remarks.

Akanthomyces bashanensis was easily identified as Akanthomyces , based on the BLASTn result in NCBI and the phylogenetic analysis of combined datasets (ITS, LSU, RPB2, TEF) (Fig. 1 ) and it has a close relationship with another new species, A. beibeiensis . A. bashanensis was easily distinguished from A. beibeiensis by its longer phialides and smaller conidia. Jeewon and Hyde (2016) recommended that a minimum of> 1.5% nucleotide differences in the ITS regions and protein coding genes may be indicative of a new species. The pairwise dissimilarities of ITS, LSU, RPB2 and TEF sequences show 11 bp differences within 569 bp (1.93%), 19 bp differences within 881 bp (2.15%), 13 bp differences within 1070 bp (1.21%) and 4 bp differences within 973 bp (0.41%) between A. bashanensis and A. beibeiensis , respectively. The pairwise dissimilarities of ITS, LSU, RPB2 and TEF sequences show 10 bp differences within 569 bp (1.75%), 20 bp differences within 881 bp (2.27%), 19 bp differences within 1070 bp (1.77%) and 4 bp differences within 973 bp (0.41%) between A. bashanensis and A. tiankengensis , respectively. Furthermore, A. aranearum (Petch) Mains and A. ryukyuensis (Kobayasi & Shimizu) Mongkols., Noisrip., Thanakitp., Spatafora & Luangsa-ard were both absent from the available sequence in NCBI and having a spider host. Comparing with the typical characteristics (Table 2 ), A. bashanensis was easily distinguished from A. aranearum by its cylindrical phialide, smaller fusiform to ellipsoidal conidia and absence of synnemata and distinguished from A. ryukyuensis by absence of teleomorphs. Thus, the morphological characteristics and molecular phylogenetic results support A. bashanensis as a new species.

Figures

Figure 1. Phylogenetic relationships amongst the new strains and their allies based on multigene dataset (ITS, LSU, RPB 2 and TEF). Statistical support values (≥ 70 % / 0.95) are shown at the nodes for ML bootstrap support / BI posterior probabilities.

Figure 3. Akanthomyces bashanensis A infected spider (Araneae) B, C PDA culture plate showing top (B) and reverse (C) sides of the colony D-H phialides and conidia. Scale bars: 10 mm (B, C); 10 μm (D-H).