What are Chytrids? Like other fungi, the microscopic, thread-like chytrids have chitin in their cell walls to strengthen them. But unlike other fungi, their gametes (reproductive cells) have flagella and can move around freely. Although some forms are parasitic on plants or insects, most chytrids live in marine or freshwater environments.
First known fossil occurrence: Precambrian.
Last known fossil occurrence: Quaternary. This group has living relatives.