From the extensive fossil record of insects found in the Early Miocene of the Rubielos de Mora basin (Teruel Province, Spain) a single, well-preserved specimen of the subfamily Eucoilinae Thomson, 1862 (Hymenoptera: Cynipoidea: Figitidae) has been identified. The palaeoentomological site of Rubielos de Mora is a Konservat-Lagerstatte constituted by lacustrine oil-shales. The specimen is the first fossil Eucoilinae from a Tertiary outcrop and it represents a new genus and species of a family (Figitidae Thomson, 1862) extremely scarce in the fossil record: Palaeogronotoma nordlanderi n. gen, n. sp. The genus belongs to Gronotoma group (Diglyphosemini Belizin, 1961 tribe) and it is closely related to the genus Gronotoma Forster, 1869, from which mainly differs in the antennal configuration, which is especially well preserved, although other diagnostic characters are studied in this paper.
