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

Fig. 4

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 CQ0592 (holotype), ex-type living cultures, CQ05921 .

Description.

Spider host completely covered by white mycelium. Colonies on PDA, attaining a diameter of 34-37 mm after 14 days at 25 °C, white, consisting of a basal felt, floccose hyphal overgrowth; reverse yellowish. Hyphae septate, hyaline, smooth-walled, 1.4-1.9 μm wide. Conidiophores mononematous, hyaline, smooth-walled, with single phialide or whorls of 2-6 phialides or verticillium-like from hyphae directly, 14.2-19.4 × 1.0-2.1 μm. Phialides consisting of a cylindrical, somewhat inflated base, 7.0-9.2 × 2.1-2.5 μm, tapering to a thin neck. Conidia hyaline, smooth-walled, fusiform to ellipsoidal, 2.0-3.3 × 2.0-2.6 μm, forming divergent and basipetal chains. Sexual state not observed.

Etymology.

Referring to its location in Beibei District.

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, CQ05692.

Remarks.

Akanthomyces beibeiensis was easily identified as Akanthomyces according to the blast 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. bashanensis . A. beibeiensis is easily distinguished from A. bashanensis by its shorter phialide and larger conidia. The pairwise dissimilarities of ITS, LSU, RPB2 and TEF sequences show 4 bp differences within 569 bp (0.7%), 8 bp differences within 881 bp (0.9%), 20 bp differences within 1070 bp (1.86%) and 2 bp differences within 973 bp (0.2%) between A. beibeiensis and A. tiankengensis , respectively. Furthermore, A. aranearum and A. ryukyuensis were both absent from the available sequences in NCBI and had spider hosts. Comparing with the typical characteristics (Table 2 ), A. beibeiensis 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. beibeiensis 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 4. Akanthomyces beibeiensis A infected spider (Araneae) B, C PDA culture plate showing top (B) and reverse (C) sides of the colony D-J phialides and conidia. Scale bars: 10 mm (B, C); 10 μm (D-J).