Paleontologists in Portugal have found several specimens from large-sized ankylopollexian iguanodontians that lived 150 million years ago (Late Jurassic epoch).
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Life reconstruction of a large-sized ankylopollexian iguanodontian dinosaur interacting with a juvenile in the Late Jurassic of Europe. Image credit: Vitor Carvalho.
The new dinosaur fossils were discovered at various localities of the Lusitanian Basin in western Portugal.
One of the specimens, labeled SHN.JJS.015, belongs to an early-diverging form of Ankylopollexia, an enigmatic group of herbivorous iguanodontian dinosaurs that lived from the Late Jurassic to the Late Cretaceous in North America, Europe, Africa, and Asia.
“It was a surprise,” said Dr. Filippo Maria Rotatori, a paleontologist with GEOBIOTEC at the Universidade NOVA de Lisboa and the Museu da Lourinhã.
“We believed that the diversity of this dinosaur group was already well-documented in the Late Jurassic of Portugal, but this discovery shows that there is still much to learn and that exciting findings may continue to emerge in the near future.”
“Unfortunately, due to the limited material recovered, we are not yet able to assign a formal scientific name to this species.”
“It was a heavyweight,” added Professor Fernando Escaso, a paleontologist at the Universidad Nacional de Educación a Distancia.
“When we estimated its size and body mass, we found that this new dinosaur was significantly bulkier than other iguanodontian species, such as Draconyx or Eousdryosaurus, with which it most likely shared the ecosystem.”
The paleontologists also unearthed a series of smaller, isolated bones in the same Lusitanian Basin.
These fossils may represent the same species of ankylopollexian iguanodontian dinosaur as SHN.JJS.015.
“The description of SHN.JJS.015 adds a new member of Ankylopollexia to the poorly known Late Jurassic iguanodontian fauna of the Iberian landmasses and confirms the coexistence, at least during the lowermost part of the Tithonian (149 to 143 million years ago), of three medium- to large-sized ankylopollexian ornithopods in south-western Europe,” the researchers said.
“Furthermore, it supports the interpretation of Europe as a pivotal region of diversification for early-diverging iguanodontians during the Late Jurassic and shows the fundamental role of Iberian landmasses in achieving a better understanding of biogeographical patterns.”
The findings appear in the Journal of Systematic Palaeontology.
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Filippo Maria Rotatori et al. 2025. Evidence of large-sized ankylopollexian dinosaurs (Ornithischia: Iguanodontia) in the Upper Jurassic of Portugal. Journal of Systematic Palaeontology 23 (1): 2470789; doi: 10.1080/14772019.2025.2470789
