Karst caves are obviously characterized by darkness, constantly low temperature, high
humidity, and oligotrophy. Previous studies
revealed that Karst caves have a high
and specific bio-diversity. A large number of troglobiont
animals had been discovered
and their evolution and speciation have been well investigated. However, the origin
and evolution of cave fungi remain unknown. In a previous study, we have identified
20 new species,
which accounted for 49% of the total number of new species
of fungi ever described
from caves. In this study, we inferred
the divergence times of these 20 new species and compared to the cave formation geologic
age. The fossil- calibrated molecular clock showed that the divergence times of these 20 suspected troglobitic fungi are between
late Miocene (7.2 Mya for Metapochonia
variabilis) and late Jurassic (158 Mya for Gymnoascus exasperates). While based on the historical
geological movement and the paleoclimate of Guizhou, it has been estimated that the
development of caves in this area was later than middle Pliocene (3.5–4
Mya). It is therefore concluded that the new species described
from these caves are unlikely troglobitic fungi but travelers from other environments.
The geographic history of caves
appeared to
be too short for fungal speciation....
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