[1] Fossils of Chimerarachne were discovered in Burmese amber from Myanmar which dates to the mid-Cretaceous, about 100 million years ago.

These fossils resemble spiders in having two of their key defining features: spinnerets for spinning silk, and a modified male organ on the pedipalp for transferring sperm.

It suggests that there used to be spider-like animals with tails which lived alongside true spiders for at least 200 million years.

[3] The two publications agree on the basic anatomy and significance of these fossils, but differ slightly in the interpretation of their position of Chimerarachne in the arachnid tree of life.

[2] The Huang et al. study placed Chimerarachne a little more distant from spiders and as part of an extinct arachnid order known as Uraraneida which are also spider-like, and have a tail, but which were not previously thought to have spinnerets.

In 2019 and 2022, Wunderlich suggested dividing an order for spiders, Araneida into suborder Araneae and Chimerarachnida, excluding Uraraneida.