Figure 1.
Comparison of cultural characteristics of the new taxa compared with E. aspergilloides and E. weberi.
(A) Escovopsis weberi ATCC 64542, ex-type; (B) Escovopsis aspergilloides CBS 423.93, ex-type; (C) Escovopsis moelleri CBS 135748, ex-type; (D) Escovopsis lentecrescens CBS 135750, holotype; (E) Escovopsis microspora CBS 135751, ex-type; (F) Escovopsioides nivea CBS 135749, ex-type. After 7 days on oatmeal agar, in 9 cm diam plates, at 25°C.
Figure 2.
(A–B) Growth habit, note stolons (long arrow) formed at the colony edge with rhizoids (short arrows) developing on the agar surface; (C–D) Details of conidiogenesis showing early development of the clavate vesicles (C, scale bar = 10 µm), and, a later stage covered with swollen, short-necked phialides (D, scale bar = 20 µm).
Figure 3.
(A–D) Older stages of vesicle development showing darkening conidia with thickened rugose walls and apical cap-like structures (arrows); note the short-lived or evanescent vesicle (D). All scale bars = 10 µm.
Figure 4.
(A–B) Details of conidiogenesis with clavate vesicles and swollen, short-necked phialides producing chains of conidia (scale bar = 20 µm); (C–D) Older evanescent vesicles with dark spores (scale bar = 10 µm); (E) Inset, showing conidial ornamentation (scale bar = 5 µm).
Figure 5.
(A–D) Stages of conidiogenesis, resulting in evanescent heads (D, arrow), all scale bars = 20 µm; (E–F) Paratype, faster-growing strain with more evanescent heads (scale bar = 10 µm), inset (G) showing detail of spore veil or coat (scale bar = 2 µm).
Figure 6.
(A–B) Conidiophores bearing both terminal and intercalary vesicles with few cylindrical, subulate phialides tapering gradually to a long neck region, and hyaline, thin-walled conidia (inset, C)—distinguished from the sphaerical darker aleurioconidia (B, left above inset); (D) Aleurioconidia emerging directly from hyphae; (E) Chlamydospores sensu lato formed in glistening white chains or ropes, densely guttulate. All scale bars = 10 µm.
Figure 7.
Details of conidiogenesis and spore morphology, as revealed by Critical-Point Drying SEM.
(A) Escovopsis moelleri, showing branching and vesicle formation (scale bar = 10 µm); (B) Detail of conidial morphology, with ornamentation and apical cap (arrows) (scale bar = 2 µm); (C) Escovopsioides nivea, chains of chlamydospores sensu lato revealing cryptic surface ornamentation or mucilaginous deposit (scale bar = 10 µm); (D–F) Escovopsioides nivea, (D) showing both terminal vesicle and phialides produced laterally on slight swelling (arrow) (scale bar = 10 µm); (E–F) Lageniform phialides with long chains of conidia (scale bar = 5 µm).
Figure 8.
Fifty-percent majority rule tree obtained from the Bayesian analysis of LSU DNA sequence data.
The Escovopsis and Escovopsioides clades are highlighted in shaded boxes. In these clades, a superscript T denotes sequences obtained from (ex-) type strains. Regular type taxa in the clade ascribe sequences obtained from GenBank, which were included for the purpose of phylogenetically placing the new species. Except for some rearrangements at the deeper nodes (see TreeBASE), this Bayesian consensus tree is topologically identical to trees obtained from maximum parsimony (MP) and maximum likelihood (ML) analyses. Numbers at tree nodes are Maximum likelihood bootstrap support values (integer value up to 100), posterior probabilities support values obtained from Bayesian analysis (fraction up to 1) and parsimony bootstrap support values (integer value up to 100), respectively. Colour taxa indicate representatives from the hypocrealean families shown on the tree. The scale bar represents the expected number of changes per site. Glomerella cingulata was used to root the tree.
Figure 9.
Single most parsimonious tree obtained from a parsimony analysis of ITS DNA sequence data.
The Escovopsis and Escovopsioides clades are highlighted in shaded boxes. In these clades, a superscript T denotes sequences obtained from (ex-) type strains. Bold type taxa are described as new species in this manuscript. This maximum parsimony (MP) tree is topologically identical to trees obtained from Bayesian (B) and maximum likelihood (ML) analyses. Numbers at tree nodes are Maximum likelihood bootstrap support values (integer value up to 100), posterior probabilities support values obtained from Bayesian analysis (fraction up to 1) and parsimony bootstrap support values (integer value up to 100), respectively. The scale bar indicates the number of changes. Based on the LSU tree, Cladobotryum asterophorum was used to root the tree.
Table 1.
Key to the genus Escovopsis and its relatives.
Figure 10.
Light microscopy of Escovopsis ex type cultures. (A–B) Escovopsis weberi ex type culture, ATCC 64542:
Spore chain still attached to phialide on cylindrical vesicle, showing the relatively early development of the pigmented outer spore wall or sheath (A); Close-up of another conidium with prominent outer sheath (B). Most conidia are older and detached before the pigmentation and separation of the outer wall or sheath become obvious. (C) Escovopsis aspergilloides ex type culture, CBS 423.93: Detached spore chain in various stages of maturation, showing pigmentation and prominent outer walls. Arrows indicate the outer caps. All scale bars = 5 µm.
Table 2.
Results of sampling of Escovopsis-like species isolated from fungal gardens of Acromyrmex spp. in Viçosa, Minas Gerais, Brazil.