The Eodiscides were a group of Agnostid Trilobites, which appeared in the late Early Cambrian and persisted till the end of the Middle Cambrian. They were small in size, with only two or three thoracic segments. Within the Eodiscina, the Weymouthiidae were a group of blind (eyeless) Trilobites lacking free cheeks, known only from the latest Early Cambrian and earliest Middle Cambrian.
In a paper published in the journal Historical Biology on 14 February 2025, Luis Collantes of the Yunnan Key Laboratory for Palaeobiology and MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment at Yunnan University, and Sofia Pereira of the Centro de Geociências at the Universidade de Coimbra, describe a new species of Weymouthiid Eodiscide Trilobite from the Upper Marian (Cambrian 'Stage 4') of Toledo Province, Spain.
The new species is described from eight isolated cephala, three isolated pygidia and six complete specimens, preserved as internal and external moulds, collected from a site within the 'metasedimentary unit’ of the Schist-Greywacke Complex of the Schist-Greywacke Complex, about 25 km to the southwest of the city of Toledo. It is given the name Toledodiscus valverdi:, where 'Toledodiscus' refers to the location where the specimens were discovered, and 'valverdi' honours the late agronomist and palaeontologist Ildefonso Recio Valverde for his contributions to the study of the palaeontology of Toledo Province and the conservation and dissemination of the palaeontological heritage of the Toledo Mountains.
Toledodiscus valverdi resembles members of the genus Serrodiscus, and in particular Serrodiscus bellimarginatus, with some specimens initially being identified as belonging to that species. However, unlike any member of the genus Serrodiscus, Toledodiscus valverdi has ocular ridges a structure usually absent in all Weymouthiids. Weymouthiids, like other Eodiscides, lacked eyes, and therefore have no obvious use for ocular ridges; some other Eodiscides do retain these structures, which are assumed to be a 'primitive' trait within the group, inherrited from a sighted ancestor. This could be interpreted as a sign that Toledodiscus is a more primitive genus than Serrodiscus, and possibly ancestral to it. However, Toledodiscus valverdi also has a well-defined occipital structure, something considered an advanced trait in Weymouthiids, and absent in all known members of the genus Serrodiscus.
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