An international team of paleontologists has discovered a trilobite fossil in the Huelva municipality of Cumbres de San Bartolomé. The finding adds to the knowledge we have about the fauna of the Cambrian, the period in which our planet witnessed an explosion of life and the first multicellular organisms appeared, more complex than the preceding sponges or jellyfish.
A history of 500 million years
The research has been headed by Huelva- born Luis Collantes , a doctoral student at the University of Coimbra, in Portugal, and a geologist at the University of Huelva. The fossil, barely millimeters in size, has been described as Chelediscus garzoni . This is the first fossil of Chelediscus that has been found in southern Europe , hence the importance of the discovery, since it represents a finding located in the western area of Gondwana , the continental block that would end up colliding with the rest of the continents to form the Pangea supercontinent. The fossil remains found are dated with a chronology of between 509 and 514 million years old . According to Luis Collantes:
“This is a new species within the genus. The morphological characters that it presents do not coincide with any of the species described to date. It is an advance regarding the knowledge of the evolutionary lineage of this group of trilobites”.
Chelediscus is a genus of trilobites described by Awa Rushton in 1966. Trilobites inhabited the planet’s seas during the Paleozoic and are a class of arthropods , the most numerous and diverse phylum in the animal kingdom. This taxonomic division includes invertebrate animals that have some type of external skeleton and articulated appendages, such as insects, spiders and crustaceans.
These trilobites were the benthic forms that dominated the marine ecosystems of the Paleozoic era . Benthos are those organisms that bury themselves in the sand, such as clams, cockles and snails, as well as those that adhere to rocks, among other characteristics. This way of living is what has allowed many trilobites to have reached us until today fossilized in the rocks that once formed part of the seabed , forming an infinity of families, genera and species to which we must add another one after the discovery made in Huelva.
Complex life makes its way
Trilobites have flat and generally oval bodies. Regardless of their size, they are characterized by having a body divided into three parts : the head, the thorax and the pygidium. However, its name responds to the “three lobes” that run longitudinally from the head to the end of the body. These are composed of the axial lobe or rachis in the central zone, flanked by the left pleural lobe and the right pleural lobe. Although they had antennae and legs, few fossils have been able to preserve these fine structures that are susceptible to decomposition before the fossilization process ends. We have remains of trilobites that measure from a few millimeters, like the protagonist of this news, up to 90 centimeters in length.
The study on the finding has been published in the prestigious journal Historical Biology. An International Journal of Paleobiology . The name of the new species, Chelediscus garzoni , is a tribute to Ignacio Garzón González , a fan of paleontology who has been carrying out important work for years promoting the study, conservation and dissemination of the geological and paleontological heritage of the Sierra de Aracena.
The genus already had specimens found in England, Newfoundland, New York, Sweden and Russia. This new discovery in Spain helps link the fauna to the ancient continents of Avalonia, Baltica, Siberia and Laurentia . In addition, it is not the first fossil to appear in the area, but the research team has carried out several work campaigns in which they have been able to locate other Cambrian fossils such as Serrodiscus , Callavia and Marocella . The new trilobite species encourages the team to continue searching for new evidence of life from such a remote past.
References:
Collantes, L. et al. 2022. First report of Chelediscus Rushton, 1966 (Trilobita) from Western Gondwana, with description of a new species from the Cambrian Series 2 of Spain. Historical Biology, DOI: 10.1080/08912963.2022.2109966.
- P. 2022. The Sierra de Huelva, scene of a paleontological discovery. huelvainformacion.es.
