Conidiobolus marcoconidius B. Huang & Y. Nie, 2024

Nie, Yong, Yin, Ying, Zhao, Heng, Liu, XiaoYong & Huang, Bo, 2024, Unveiling species diversity within the family Conidiobolaceae (Entomophthorales) in China: Descriptions of two new species and reassessment of the taxonomic position of Conidiobolus polyspermus, MycoKeys 105, pp. 203-216 : 203-216

Conidiobolus marcoconidius B. Huang & Y. Nie sp. nov.

Fig. 3

Etymology.

marcoconidius (Lat.), referring to its large primary conidia.

Known distribution.

Anhui Provinces, China.

Typification.

China, Anhui Province, Hefei City, Dashushan National Forest Park , 31 ° 84 ′ N, 117 ° 17 ′ E, from plant debris, 15 Mar. 2022, Y. Yin, holotype DSS 20220315 . Ex-type culture RCEF 6918 . GenBank: nucLSU = PP 034289 ; EFL = PP 035213 ; mtSSU = PP 034293 .

Additional specimens examined.

China, Anhui Province, Hefei City, Binhu National Forest Park , 31 ° 73 ' N, 117 ° 38 ' E, from plant debris, 10 May 2022, Y. Yin ,, culture RCEF 7412 . GenBank: GenBank: nucLSU = PP 034290 ; EFL = PP 035214 ; mtSSU = PP 034294 .

Description.

Colonies on PDA at 21 ° C after 3 d white, reaching ca 8 mm in diameter. Mycelia colorless, unbranched at the edge of colony, distended to a width of 9–20 μm segment after 5 d. Primary conidiophores unbranched, slightly curved at the tip, producing a single primary conidium, without widening upward near the tip, 105–230 × 10–16 μm. Primary conidia forcibly discharged, mostly globose, sometimes obovoid, 45–67 × 42–58 μm, with a sharp or round papilla, 13–22 μm wide, 4–13 μm long. Secondary conidia arising from primary conidia, with a short or long secondary condiophore, similar and smaller to the primary conidia. Secondary conidiophores branched at the base or tip, thus bearing 2 secondary conidia at each tip. Sometimes form 2–5 secondary conidia like “ tomatoes on sticks ” from small to large at each branch. Microconidia not observed on the PDA culture and on the 2 % water agar. Zygospores formed between adjacent segments after 7 days, smooth, globose, 30–45 μm in diameter, with a 2–4 μm thick wall.

Notes.

Conidiobolus marcoconidius is distinguished morphologically by its larger primary conidia compared to other Conidiobolus s. s. species, with the exception of C. coronatus ( King 1977) . Notably, it can be readily differentiated from C. coronatus by the absence of villose spores ( Batko 1964). Additionally, C. marcoconidius is characterized by secondary conidiophores that branch at the base, giving rise to 2–5 secondary conidia resembling “ tomatoes on sticks ” at each branch, varying in size from small to large. In the phylogenetic tree, it forms a discrete clade, setting it apart from other Conidiobolus s. s. species.

Figures

Figure 3. Conidiobolus marcoconidius RCEF 6918 a colony on PDA after 3 d at 21 ° C b mycelia unbranched at the edge of the colony c hyphal segments d – f primary conidiophores g – j primary conidia k, l primary conidia bearing a single secondary conidium m secondary conidiophore branched at the base and bearing two secondary conidia at each tip n secondary conidiophore branched at the tip o secondary conidiophore branched at the base bearing 2-5 secondary conidia at each branch p, q zygospores formed between adjacent segments of the same hypha r mature zygospores. Scale bars: 100 μm (b, n); 20 μm (c – m, o – r).