Palaebiology of the amiiform fishes from Early Cretaceous of Las Hoyas: An integrative multidisciplinary approach

• Autores: Hugo Martín Abad
• Directores de la Tesis: Francisco José Poyato Ariza (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2015
• Idioma: inglés
• Tribunal Calificador de la Tesis: Ángela Delgado Buscalioni (presid.), Óscar Cambra Moo (secret.), Romain Vullo (voc.), Martha Richter (voc.), José Joaquín Moratalla García (voc.)
• Materias:
  • Ciencias de la vida
    • Biología animal (zoología)
      • Ecología animal
    • Paleontología
      • Paleontología de los vertebrados
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • The fossil record of the Early Cretaceous (Barremian) of Las Hoyas includes three taxa of amiiform fishes. These taxa, traditionally assigned to the species Caturus tarraconensis, Amiopsis woodwardi and Vidalamia catalunica, represent actually three new species. These species are the basis for a multidisciplinary study whose objective is to comprehend the palaeobiologý of these fishes in the context of a wetland ecosystem. From a phylogenetic point of view, one of the species represents a primitive lineage, with a mosaic combination of characters from both caturoids and amioids. The second species is classified as plesion Vidalamiinae, and the third oneas a member of this same subfamily. A palaeobiogeographic study of the order Amiiformes, including the three species from Las Hoyas, shows that the record of this group extends from at least the Early Jurassic to Recent times, reaching its maximum diversity during the Cretaceous. Its historical distribution is mainly explained by a series of vicariant events that originated from the Tethys Sea. The osseochronometric analysis of the growth cessation marks detected in the scales of the three species shows that they presented different growth profiles. Growth of amiiform fishes seems to have a phylogenetic component, and to be strongly influenced by environmental conditions, especially temperature. Actuotaphonomical experimentation of decay in extant fish carcasses confirms that a freshwater environment favors a total degradation of tissues. In consequence, the presence of a protection mechanism, such as microbial mats, is needed to justify the exceptional preservation of the fossil record from Las Hoyas. Additionally, this experimentation shows that carcasses suffer abrasion by transport even in very low energy systems. Absence of evidence of abrasion in the fossil fishes of Las Hoyas suggests that the association of this site is autochthonous in origin. Autochthony of the association allows to interpret the sample of each of the three species as representative of their original populations. An analysis of the population structure of these species shows that they presented habitat partitioning: juvenile and adult individuals did not inhabit the same environment. The ecological role played by the three species in the palaeowetland of Las Hoyas would be different both ontogenetically within each species and interspecifically.