In November 2018, while walking along Caniçal beach, in the municipality of Lourinhã, Portugal, known for having been home to dinosaurs and other prehistoric animals, amateur paleontologist Filipe Vieira spotted what appeared to be fossils embedded in sedimentary rocks that, in high tide, they are covered. He managed to collect some fragments and sent them to the Portuguese paleontologist Alexandra Fernandes, from the Lourinhã Museum.
“What caught his attention were the dark teeth of a pterosaur, which contrasted with the lighter stones”, says Fernandes. With Brazilian paleontologists, she led the analysis of the findings that indicated that it was a new species of pterosaur, Lusognathus almadravathe first described in Portugal, as published in September in the scientific journal PeerJ.
The winged reptile must have lived in the region around 149 million years ago, during the Jurassic period. The rocks, quite hard and compact, provided work for the museum team that excavated the fossil fragments in March 2019. “It was necessary to saw the stones during the few hours when the tide was low”, reports Fernandes. The researchers managed to remove the anterior part of the jaw from L. almadrava, with 29 teeth and fragments of two other loose teeth. The fossil also included three fragmented neck vertebrae.
The spatula-shaped snout, about 20 centimeters (cm) long and 5 cm wide, the slightly horizontal comb-shaped dentition, in addition to the pronounced cavities where the teeth are housed (dental alveoli), allowed researchers to infer which belonged to the subfamily Gnathosaurinae. “His teeth reached 23 millimeters [mm] long and around 5 mm wide, more robust and thicker than those of other species in the subfamily”, observes Fernandes, who is doing his PhD at the Department of Earth and Environmental Sciences at the Ludwig Maximilian University of Munich, Germany.
This characteristic signals a diet composed mainly of fish. “Its expanded jaw indicates that this animal probably opened its mouth to get water with whatever was in it; the liquid ran down the sides and the teeth retained the prey”, explains Brazilian paleontologist Alexander Kellner, director of the National Museum of the Federal University of Rio de Janeiro (MN-UFRJ), who participated in the characterization of the new species and is one of the authors of the article.
For this reason, the species gained the name almadrava, a traditional Portuguese fishing trap. Lusognathus comes from the Latin “lusus”, in reference to Lusitânia (name of the area of Portugal in Roman times), and “gnathus”, jaw. This feeding habit led researchers to conclude that the species would live in estuarine areas with shallow waters, tidal flats, coastal swampy areas or even inland lakes.
Based on the fossil fragments found, they also estimated that the winged reptile had a wingspan of 3.6 meters (m), which would make it a large animal – in general, pterosaurs at that time were between 1.6 m and 1.8 m from one wing tip to the other, while those from the Cretaceous (between 145 million and 65 million years ago) reached well over 3 m, the researchers argue in the article.
Given this new development, they suggest that this growth in winged reptiles may have started earlier than previously assumed and may have contributed to pterosaurs eventually occupying an ecological niche different from their competitors, birds. Furthermore, its large size could indicate an ecosystem rich in prey.
Despite being the first species of pterosaur described in Portugal, these are not the first fragments found in the country. Since the 1950s, fossils of other winged reptiles have been found, such as teeth and parts of a femur, as well as traces of footprints, but because they are very fragmented, it has not yet been possible to identify which species they belonged to. “One of the reasons for the difficulty is that the bones of these animals are hollow inside, more fragile, and the types of rocks in the country do not seem to preserve them so well”, says Fernandes.
Kellner adds that the characteristics of the place where the fossil was found, a coastal area, may also interfere with the preservation of these fragile bones, because the rocks that contain them are subject to continuous tidal movement, which contributes to faster erosion. “But where there is one, there may be more. I hope to be able to carry out field work in the region. The discovery left us excited”, says the Brazilian, elected in June to the Lisbon Academy of Sciences.