Fossils of a tiny creature which lived before the existence of dinosaurs have been found in Aberdeenshire.
The flea-like creatures lived 410 million years ago
The tiny relics which are less than two millimetres long are the remains of cladocerans, or water fleas, which lived 410 million years ago.
Experts at the National Museum of Scotland said the discovery, in the world-renowned cherts sediments at Rhynie, was of global importance.
They said it explained the mystery of what the first freshwater fish fed on.
The previously oldest known cladoceran, which was found in 1991, dated back to early Cretaceous times, and is about 300 million years younger than the Scottish fossil.
These latest fossil forms were found by a team of German palaeontologists who had travelled to the Rhynie cherts in Aberdeenshire to look for plant fossils.
They were then passed on to Dr Lyall Anderson of NMS and his team for identification.
"We are used to going out and looking for plant and animal fossils, but this is an unusual animal in an unusual setting and something that we don't have a fossil record of," said Dr Anderson.
"Normally we get about one or two fossils, but we have about 40 of this species.
"We believe that they were what the first freshwater fish were feeding on at the time, which has been a bit of a mystery until now."
Researchers have named the freshwater crustaceans Ebullitiocaris oviformis. This relates to the creatures' egg-like shape and the fact they were found in a hot spring.
The species swam upright by pulsating their feathery antennae and are thought to have died out during the process of evolution.
The world-renowned cherts sediments at Rhynie were laid down by hot springs and geysers when Scotland was affected by volcanic activity.
When the waters erupting from the geysers cooled, they preserved plants and animals in three-dimensional detail.