Gibellula pigmentosinum Tasanathai, Kuephadungphan & Luangsa-ard sp. nov. Figure 4

Typification.

Thailand. Nakhon Ratchasima, Khao Yai National Park, Mo Sing To Nature Trail; 14°711'N, 101°421'E; on Storenomorpha sp., attached to underside of unidentified dicot leaf; 10 February 2010; K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, T. Chohmee, R. Ridkaew, A. Khonsanit (Holotype no. BBH 28509, ex-type culture no. BCC 41203, isolated from ascospores and BCC 41204, isolated from conidia). GenBank (BCC 41203): ITS = MT477071, TEF1 = MT503330, RPB1 = MT503323.

Etymology.

Refers to the capability of the fungus to produce pigmentosins.

Description.

Spider host completely covered by white to yellowish-white mycelial mat. Synnemata solitary or in pairs, cylindrical, white, becoming yellowish-white at the base (Fig. 4a). Conidiophores arising along the entire length of the outer hyphae of synnemata and from the mycelia covering the host, crowded, smooth to verrucose, (55-)97.5-170(-226) × (5-)7-10(-12.5) µm, narrowing to a slender apex, and terminating in a swollen vesicle, metulae, phialides bearing conidia, forming a spherical conidial head (Fig. 4a, f). Conidial heads (25-)30-39(-45) µm diam (Fig. 4g). Vesicles mostly globose, (4.5-)5.5-9(-10) µm diam (Fig. 4g). Metulae borne on a vesicle, broadly obovoid, (5.5-)6-8(-10) × (3-)4-6(-7.5) µm (Fig. 4g), bearing phialides. Phialides obovoid to clavate, with a distinct short neck, (5-)5.5-8(-9) × 2-3(-4.5) µm (Fig. 4g). Conidia produced on a phialide, obovoid with an acute apex, (2.5-)3.5-5(-5.5) × 1-2(-3) µm (Fig. 4h). Perithecia produced on the mycelial mat on the head and body of the spider, scattered, superficial with loose mycelia covering only the bottom one-fourth of the perithecium, ovoid, reddish-yellow, (790-)882-1,117(-1,150) × 300-443(-475) μm (Fig. 4a, b). Asci cylindrical, 700-750 μm long, (4.5-)5-6(-7) μm wide, ascus cap (4-)5.5-6.5(-7) × 3.5-4(-5.5) μm (Fig. 4c). Ascospores filiform, multiseptate, arranged in parallel rows, (666-)670-727(-730) × 2-3 μm, often breaking into 128 part-spores (Fig. 4d). Part-spores bacilliform with apices rounded, (3.5-)4-7(-9) × 1-1.5(-3) μm (Fig. 4e). Granulomanus -like asexual morph occasionally present, forming irregularly branched hyphae bearing mono- or polyblastic phialides. Phialides irregularly in shape, mostly smooth, with one or more conspicuous denticles. A conidium borne on each denticle, long, filiform, (16-)16.5-21.5(-22.5) × 1-1.5 μm (Fig. 4i).

Culture characteristics.

Colonies derived from ascospores, on PDA slow-growing, attaining a diam of 1.5 ± 0.2 cm in 4 weeks at 25 °C, white, floccose; reverse light brown, darkening with age toward center (Fig. 4j). Sporulation not observed.

Additional specimens examined. Thailand, Nakhon Ratchasima, Khao Yai National Park, Mo Sing To Nature Trail; 14°711'N, 101°421'E; on Storenomorpha sp., underside of unidentified dicot leaf; 13 August 2009; K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, T. Chohmee, R. Ridkaew (BBH 26516, BCC 38246 and BCC 38955); on Araneida, underside of unidentified dicot leaf; 11 September 2009; K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, T. Chohmee, R. Ridkaew (BBH 27081, BCC 39707 and BCC 39708); on Storenomorpha sp., underside of unidentified dicot leaf; 7 April 2010; K. Tasanathai, S. Mongkolsamrit, T. Chohmee, A. Khonsanit, R. Ridkaew (BBH 28533, BCC 41870 and BCC 41871).

Notes.

Gibellula pigmentosinum shares similarity with G pulchra (Mains 1950) in producing cylindric, yellowish white synnemata bearing aspergillate conidiophores with fusoid-ellipsoid conidia and superficial, reddish brown, ovoid perithecia containing bacilliform part-ascospores. The synnemata in G pulchra are more copious and sometimes more violaceous than in G. pigmentosinum . Remarkably, G. pigmentosinum distinctly differs from G pulchra in having a granulomanus-like conidial state.