Abstract
We describe a new assemblage of frog crabs (Raninoidea) from the lower Eocene Serraduy Formation in Huesca, Northeastern Spain, representing five species from five genera and four subfamilies, from which there are two new genera and four new species: i.e., Alloranina arjae gen. et sp. nov. (subfamily Ranininae), Huescarina vanbakeli gen. et sp. nov., Notopoides ovaloides sp. nov., Quasilaeviranina arafita sp. nov. (subfamily Raninoidinae), plus another indeterminate raninoid species. Although Eocene raninoids are represented by > 100 species in 32 genera worldwide, they are mainly associated with siliciclastic environments, contrasting with the material here studied, associated to a reef environment surrounded by muddy substrates and linked to a rich invertebrate fauna. Besides the abundance and diversity of the new assemblage, it preserves some of the oldest representatives of a modern genus ( Notopoides ), emphasizing the importance of the Eocene epoch for understanding the origins of modern groups. UUID: http://zoobank.org/pub:9E78087F-E0C3-4420-AB69-2FE100CAE848 .