The earliest true fungal lineages likely resembled modern chytrids. Aquatic Produced flagellated (swimming) spores Fed by external digestion (already a defining fungal trait). This is before large animals dominate land.

Evolution

LECA: Likely Sexual Reproduction

~1.75 billion years ago (+/- 50 million)

Last Eukaryote Common Ancestor

Unikonts: Single-Motor flagella Reform

~1.3 Billion Years Ago (+/- 100 million)

Transition to a Single Flagellum

Opisthokonts: True Posterior Flagellum

~1.15 Billion Years Ago (+/- 50 million)

12 unique amino acids + glycogen energy storage + True Posterior Flagellum

Oogamy: Sperm-Egg Sexual Reproduction

Sperm and egg cell on microscope. Scientific background.

~1.1 Billion Years Ago (inferred, +/- 100 million)

Sperm-like gamete and egg-like gamete

Fungi Ancestors Split Off: (aquatic Holomycota)

~950 Million Years Ago (+/- 50 million)

External digestion + chitin cell walls

Living Fossils: Chytrids

~600 Million years ago (+/- 20 million)

Sperm-like reproduction to spread seed to new soil.

450 mya Fungal Underground Alliance

~450 Million years ago (+/- 10 million)

Arbuscular mycorrhizae (Glomeromycota symbiosis)

420 mya Fungal Giants of the Devonian

~420 MYA (+/- 20 million)

Large upright fungal structures (e.g., Prototaxites)

Fungal Survivors of Extinction

~252 MYA (Permian–Triassic boundary)

Massive fungal proliferation after extinction