Pararhexoacrodictys catolensis Cantillo & Gusmão, 2019

Cantillo, Taimy, Almeida, Davi Augusto Carneiro De, Monteiro, Josiane Santana & Gusmão, Luís F. P., 2019, Pararhexoacrodictys (Incertae sedis, Ascomycetes) gen. nov., new combinations and new records of hyphomycetes from Brazil, Phytotaxa 397 (2), pp. 199-209 : 201-203

Pararhexoacrodictys catolensis Cantillo & Gusmão sp. nov. Fig. 1

MycoBank: MB 824303

Etymology: — referring to Catolés, the locality where this taxon was discovered.

Colonies effuse, brown to dark brown on natural substrate. Mycelium inmersed, branched septate pale brown hyphae, 2–3 μm diam. Conidiophores mononematous, macronematous, solitary, erect, straight or flexuous, septate, cylindrical, smooth, dark brown to almost black, paler at the distal end, 200–300 × 20–30 μm at the swollen base, 5–10 μm wide above the base. Conidiogenous cells monoblastic, integrated, terminal, lageniform, with 1–6 percurrent extensions, brown to pale brown, smooth, 7.5–10 × 5 μm wide at base. Secession rhexolytic. Conidia solitary, dry, acrogenous, holoblastic, subglobose, globose or turbinate, septate, smooth, brown to light brown, 25–41 × 25–30 μm. Basal cell distinctly protuberant, cuneate, broadly truncate with 15–17.5 μm wide at the upper part and 2.5–4 μm wide at lower part, with 2–4 suprabasal cells. Appendages 3–6 (mostly 4), not continuous, undulate, 0–3 septate, smooth, slightly swollen and rarely bifurcated at apex, pale brown to subhyaline, becoming hyaline at apex, 10–16.5 μm long, 3.5 μm wide at base.

Material examined:— BRAZIL. Bahia: Mata da Florquilha - Catolés, Abaíra , 13°17’S 41°54’W. 10 January 2015, from submerged bark tree, T. Cantillo s.n. ( HUEFS 203035 Holotype; HUEFS 203036 Isotype). Idem, from terrestrial dead leaf, J.S. Monteiro s.n. ( HUEFS 216699 Paratype) .

Notes:— Pararhexoacrodictys catolensis have up to 6 septate appendages located in the upper-medium part of the conidium. Conidial appendages are not always continuous with the conidial body and septa must to be observed very carefully; septa at distal end of the appendages appear as almost inconspicuous due to the transparency in this zone. Bifurcate appendages and bilobulated conidia were rarely observed and conidial surface collapses and peels off when mounted in PVL.

Some Pseudoacrodictys spp. with presence of conidial appendages are morphologically similar to Pa. catolensis . In particular, Ps. limoniaceae Y.R. Ma & X.G. Zhang (2016: 71) and Ps. corniculata (R.F. Castañeda) W.A. Baker & Morgan-Jones (2003: 378) by its conidial shape and appendages placement in the upper part of the conidium. However, Ps. limoniaceae have appendages with a distinctive horn-like appearance ( Ma et al. 2016) and conidia are slightly bigger; Ps. corniculata , on the other hand, have 3–4 appendages, tightly clustered at the conidial apex and also have cylindrical conidiogenous cells ( Baker & Morgan-Jones 2003); this authors also particularize that the conidia in Ps. corniculata as well as those in Ps. viridescens (B. Sutton & Alcorn) W.A. Baker & Morgan-Jones (2003: 388) may be released in some cases by an irregular tear in the proximal conidiophore periclinal wall, but they did not considered this phenomenon equal with the detachment observed in species of Rhexoacrodictys , arguing that the rhexolytic break that occurs evenly at a narrow well-defined zone of dehiscence cannot be observed in either of those species of Pseudoacrodictys .

When compared with Ps. eickeri (Morgan-Jones) W.A. Baker & Morgan-Jones (2003: 386) , appendages in both species are undulate, not continuous with the conidial body and have a localized placement, but this species have aseptate appendages located in the central and distal portion of the conidia whereas in Ps. catolensis they are mostly located in the distal axis. Moreover, conidiogenous cells in Ps. eickeri are cylindrical and conidia are broadly pyriform to turbinate and larger (38–64 × 22–42 μm), so these two species could be easily separated. Compared with Ps. fici Y.D. Zhang & X.G. Zhang (2011: 262) and Ps. steviae Rashm. Dubey & A.K. Pandey (2012: 251) , they also have septate appendages clustered distally, but straight and in some way with “intact” morphology and also they do not have extensions in conidiophores or conidiogenous cells ( Zhang et al. 2011, Dubey & Pandey 2012).

Geographical distribution:— BRAZIL. Bahia: Abaíra (this paper).

Figures

FIGURE 1. Pararhexoacrodictys catolensis: A–D, G, H conidia; E, F, I, J conidiophores and conidia; G: collapsed conidia showing cracked and peeled-off walls. (A, B, E from paratype HUEFS 216699; C, D, F- J from holotype HUEFS 203035). Arrows showing slightly-pigmented secession zone. Bars =20 μm.