Acrocalymma chuxiongense Y. W. Liu & X. Y. Zeng, 2022

Liu, Yu-Wei & Zeng, Xiang-Yu, 2022, Acrocalymma chuxiongense sp. nov., a new species of Acrocalymmaceae (Pleosporales) on leaves of Quercus, Biodiversity Data Journal 10, pp. 89635-89635 : 89635

Acrocalymma chuxiongense Y. W. Liu & X. Y. Zeng sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: IFRD9449 ; recordedBy: Liu Yu-Wei; occurrenceID: living culture IFRDCC3104; Taxon : scientificName: Acrocalymma chuxiongense; kingdom: Fungi ; class: Dothideomycetes ; order: Pleosporales ; family: Acrocalymmaceae ; genus: Acrocalymma ; Location : country: China; stateProvince: Yunnan; county: Mouding ; locality: Huafo Mountain ; locationRemarks: Yunnan, Mouding , Huafo Mountain , 2021.10.7, Liu Yu wei; verbatimCoordinates: 25°19'8"N 101°25'7"E; Identification: identifiedBy: Yu-Wei Liu; dateIdentified: 2022; Record Level: language: en

Description

Habitat terrestrial, epiphytic with dome-shaped black protrusions on living leaves of Quercus sp. Teleomorph: Ascomata 50-80 µm high, 270-320 µm in diam. (average = 70 × 280 µm, n = 10), dark brown, gregarious, erumpent to nearly superficial, visible as numerous, raised, dome-shaped areas on host surface, globose, uni-loculate, glabrous with rough walls, coriaceous. Peridium 10-30 µm wide, of unequal thickness, composed of dark brown to black cells, arranged in textura angularis. Asci 130-170 × 40-45 µm, (average = 150 × 40 µm, n = 20), 8-spored, bitunicate, pedicel furcate, apically rounded with an ocular chamber. Ascospores 35-45 × 18-20 µm, (average = 40 × 20 µm, n = 40), overlapping, bi-seriate, hyaline, obovoid to ellipsoid, 1-septate, constricted at the septum, with conically rounded ends, upper cell larger than lower cell, smooth-walled (Fig. 2 ). Anamorph: Undetermined.

Culture Characteristics: Colonies grew on PDA at 250C in the dark and reached 4 cm in diam., within 14 days, dense, circular, slightly raised in the middle, entire margin off-white to grey in surface view.

Etymology

The specific epithet reflects Chuxiong, from where the specimen was collected.

Notes

The teleomorph of Acrocalymma chuxiongense was similar to A. pterocarpi , but can be distinguished by the shape and size of ascospores. Our new collection has a larger ascospore (35-45 × 18-20 µm) than Acrocalymma pterocarpi (17-21 × 3-5 µm) ( Jayasiri et al. 2019). The shape of ascospores of the new collection is obovoid to ellipsoid, while Acrocalymma pterocarpi has fusiform ascospores. Additionally, the upper cells of our new collection’s ascospores are larger than the lower cells, while the upper and lower cells of A. pterocarpi are similar in size. Phylogenetic analysis, based on ITS and LSU sequence data, showed that Acrocalymma chuxiongense forms a distinct lineage sister to A. pterocarpi (Fig. 1 ). The GenBank accession number for TEF of our new isolate is ON604684. A comparison of the ITS and LSU nucleotides of A. chuxiongense and A. medicaginis (the type) reveals 10 (2%) and 3 (1%) nucleotide differences. Comparing the ITS and LSU nucleotides of A. chuxiongense and A. pterocarpi , there are 11 (3%) and 5 (1%) nucleotide differences, respectively.

Figures

Figure 1. Bayesian Inference (BI) phylogenetic tree, based on a combined dataset of partial LSU and ITS sequence data. Bootstrap support values for ML equal to or greater than 50 %, Bayesian posterior probabilities equal to or greater than 0.9 are shown as ML / BI above the nodes. The new isolates are in red. The scale bar represents the expected number of nucleotide substitutions per site. The tree was rooted with Acrocalymma aquaticum (MFLUCC 11 - 0208).

Figure 2. Acrocalymma chuxiongense (IFRD 9449). a-d Ascomata on living leaves of Quercus sp.; e Vertical sections through a ascoma; f-h Asci; i Ocular chamber; j Pedicel; k-n Ascospores. Scale bars: b = 2000 µm, c = 1000 µm, d = 500 µm, e-h = 50 µm, i-n = 25 µm.