Carla Sousa Santos is part of the team that discovered a new endemic species in the Sado basin

MARE researcher Carla Sousa Santos is part of the team responsible for a recent discovery: a new species of fish endemic to the Sado river basin.

With a scientific name designed to honour the Setúbal region, or Caetobriga as it was called by the Romans, Squalius caetobrigus is the latest discovery in the Sado river basin. Commonly known as scalo-do-sado, this grey and golden freshwater fish is no bigger than 20 cm and is the most recent member of the scaly species family in Portugal.

It was through genetic studies that the team of researchers managed to realise that it was a different lineage from the others. In addition, using computerised tomography, it was possible to carry out a detailed analysis of the bones of these fish, allowing them to be compared with other species. This analysis showed some differences from other Iberian Peninsula scaly species, such as the number of scales on the lateral line and certain characteristics of the skull bones.

Since most of the Iberian Peninsula's scaly species are threatened, these comparisons were made with fish from the collections of the National Museum of Natural Sciences in Madrid. In this way, it was possible to minimise environmental impacts and the sacrifice of more animals for the study.

Although it has only recently been identified and does not yet have an official threat status, the dusky scaly may already be subject to various threats: alteration and degradation of the watercourses it inhabits, the introduction of species and climate change are the main risk factors.

To access the article describing the species, click HERE.

Photographs by Carla Sousa Santos