Phylum:Ascomycota >> Class: Ascomycetes >>  Order: Eurotiales 
 BCRC Number NO BCRC Number!  
 Scientific Name: Thermoascus crustaceus

Anam: Paecilomyces crustaceus Apinis & Chesters, Trans. Br. mycol. Soc. 47: 429. 1964.

Thermoascus crustaceus (Apinis & Chesters) Stolk, Antonie van Leeuwenhoek 31: 272. 1965.

 Description: Colonies on YpSs, growing very well, attaining all plate at 40°C in 3 days, bearing prostrate and aerial hyphae, granules scattered, covered by erect hyphae, sometimes forming sectors. The color was white at first, Antimony Yellow to Cadmium Orange; reverse Orange Chrome to Orange Rufous. At 35 °C, aerial mycelium sparse and granules more abundant than those of 40°C. Ascomata originating from ascogonial coils, nonostiolate, scattered to confluent, mostly confluent forming a crusty layer, covered by aerial hyphae. Ascomata globose to irregular in shape 200-400 × 280-500 μm. Color white at first. Yellow, Yellow orange, reddish orange. Ascomal wall consisting of a few layers of pale yellowish brown pseudoparenchyma cells. Asci single, hyaline, mostly 8-spored, subglobose to pyri-form, 11.5-12.5 × 13-16 μm, thin-walled, evanescent at maturity. Ascospores pale yellowish green, mostly elliptical, 4.5-5.1 × 6.0-7.5 μm, rarely globose to subglobose, 4.5-5 μm in diam., the surface with fine echinulations and some spores with 1-3 warty structures. Conidiophores septate, hyaline to pale yellow, smooth, arising from prostrate and aerial hyphae, irregularly branched on the upper part of conidiophores, measuring 3.5-5.5 × 6.8-36 μm, the apex of each branch bearing phialides with a long conidium-bearing neck. Phiandes 4.5-6 × 14.5-30 μm, either solitary or in irregular verticils of 2 or 3 at the tip of branches. Conidia smooth, pale yellow, at first cylindric, then elliptical, measuring 2.5-4.5 × 5-8.5 μm, or sometimes becoming globose or subglobose, 4.5-5 μm. in diam.

Taiwan: Yunlin Hsien, Yunlin, low land cultivated soils of peanut, 4.IV. 1985. K-Y Chen 8504-10.

 Habitat: Cultivated soils of peanut

England, Japan, Taiwan


Chen, KY. and Chen, ZC. 1996; Stolk, AC. 1965; Udea, S and Udagawa, SI. 1983.


K. Y. Chen

 Note: Temperature tests: The optimum growth temperature was between 30°C and 40°C. Asco-mata were very abundant between 35°C and 40°C, abundant at 30°C . Asexual structures were very abundant at 30°C, abundant at 35°C and 40°C. Variations in phialide-bearing branches occurred at 40°C, including: (1) the width of the upper part of branches swelling up from 3.5-5.5 μm at 30 °C to 12 μm ( 6-12 μm) at 40°C (fig. 2) ; (2) the number of phialides at the end of branches, increased up to 8 or more at 40°C, from 2 to 3 at 30 °C; (3) mature conidia varied from elliptical at 30°C to globose at 40°C and (4) phialides becoming shorter at higher temperature, i.e., from 14.5-30 μm at 30°C to 6-12 μm at 40°C. The swelling of phialide-bearing branches at 40°C in our isolates was also recorded for T. aegyptiacus by Ueda & Udagawa (1983). The effect of temperature on size of phialides was not mentioned by Stolk (1965). However, this feature of the present isolate appear to be similiar to Stolk's isolate (1965) at 30°C-35°C and to Awao and Mistugi's isolate (1973) at 40°C.