Mushrooms are rarely found in fossil records since little in the structure of a soft mushroom can be fossilized—most eventually decay, leaving no imprint. But in 1990, two researchers in the Dominican Republic discovered a fossil of a fleshy, gilled mushroom. The mushroom, Coprinites dominicana, is about thirty-five to forty million years old (although this is debated) and is now one of five known fossil mushrooms from the tropics—together they are called coprinites. Microscopic examination suggests they are related to modern-day inky-cap mushrooms.