Publication Date:
2024-03-06
Description:
Amylascus is a genus of ectomycorrhizal truffles within Pezizaceae that is known from Australia and
\ncontains only two described species, A. herbertianus and A. tasmanicus. Species of Amylascus are closely related
\nto truffles (Pachyphlodes, Luteoamylascus) and cup fungi (Plicariella) from the Northern Hemisphere. Here we
\nreevaluate the species diversity of Amylascus and related taxa from southern South America and Australia based
\non new morphological and molecular data. We identify previously undocumented diversity and morphological variability in ascospore color, ascospore ornamentation, hymenial construction, epithecium structure and the amyloid
\nreaction of the ascus in Melzer\xe2\x80\x99s reagent. We redescribe two Amylascus species from Australia and describe seven
\nnew Amylascus species, five from South America and two from Australia. This is the first report of Amylascus species from South America. We also describe the new South American genus Nothoamylascus as sister lineage to
\nthe Pachyphlodes-Amylascus-Luteoamylascus clade (including Amylascus, Luteoamylascus, Pachyphlodes, and
\nPlicariella). We obtained ITS sequences of mitotic spore mats from Nothoamylascus erubescens gen. & sp. nov.
\nand four of the seven newly described Amylascus species, providing the first evidence of mitotic spore mats in
\nAmylascus. Additional ITS sequences from mitotic spore mats reveal the presence of nine additional undescribed
\nAmylascus and one Nothoamylascus species that do not correspond to any sampled ascomata. We also identify
\nthree additional undescribed Amylascus species based on environmental sequences from the feces of two grounddwelling bird species from Chile, Scelorchilus rubecula and Pteroptochos tarnii. Our results indicate that ascomata
\nfrom Amylascus and Nothoamylascus species are rarely collected, but molecular data from ectomycorrhizal roots
\nand mitotic spore mats indicate that these species are probably common and widespread in southern SouthAmerica.
\nFinally, we present a time-calibrated phylogeny that is consistent with a late Gondwanan distribution. The time since
\nthe most recent common ancestor of: 1) the family Pezizaceae had a mean of 276 Ma (217\xe2\x80\x93337 HPD); 2) the
\nAmylascus-Pachyphlodes-Nothoamylascus-Luteoamylascus clade had a mean of 79 Ma (60\xe2\x80\x93100 HPD); and 3)
\nthe Amylascus-Pachyphlodes clade had a mean of 50 Ma (38\xe2\x80\x9362 HPD). The crown age of Pachyphlodes had a
\nmean of 39 Ma (25\xe2\x80\x9342 HPD) and Amylascus had a mean age of 28 Ma (20\xe2\x80\x9337 HPD), falling near the EoceneOligocene boundary and the onset of the Antarctic glaciation (c. 35 Ma).
Keywords:
ectomycorrhizae
;
fungal systematics
;
hypogeous
;
mitotic spore mat
;
new taxa
;
Patagonia
;
Pezizaceae
;
Pezizales
;
Southern Gondwana
Repository Name:
National Museum of Natural History, Netherlands
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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