The study focused on the reddish geological strata of Buntsandstein facies of the Montseny area (Catalonia, Northeast Spain) dating to the Anisian stage, between 242 and 245 million years ago. In this zone, researchers identified eight different tooth types belonging to several extinct animal groups, including capitosaurid temnospondyls (large amphibians resembling externally modern crocodiles), archosauromorphs (ancestors of dinosaurs and modern crocodiles), and procolophonids (small, robust-bodied herbivorous reptiles).

“Our work aims to fill a knowledge gap regarding tetrapod communities—four-legged animals—of the Middle Triassic in equatorial Pangea”, explained Marc Riccetto, lead researcher of the study from the ICP-CERCA. At that time, all the Earth's landmasses formed a single supercontinent known as Pangea, and present-day Catalonia was near the equator. “In this study, we analyzed different dental morphologies and insertion types to better understand the diversity and ecological roles of extinct animals that inhabited what we now call Montseny, though it looked very different millions of years ago”, Riccetto noted

One of the study's most significant findings was the description of a new procolophonid reptile species, Kapes signus. Procolophonids were small reptiles that emerged at the end of the Permian and persisted until the Late Triassic, approximately 200 million years ago. During the Triassic, they had an almost cosmopolitan distribution, with various genera known worldwide. The Montseny discovery expands the known paleogeographic range of the genus Kapes, previously restricted to four species described in Russia and one in the United Kingdom. The new species, Kapes signus, exhibits unique dental characteristics not observed in other species of the genus.

Image 1. Left maxilla of Kapes signus with five preserved teeth (Arnau Bolet / © Institut Català de Paleontologia Miquel Crusafont).

“The presence of a new procolophonid species is particularly exciting”, highlighted Josep Fortuny, senior author of the investigation and researcher at ICP-CERCA. “Kapes signus not only adds to our knowledge of procolophonid biodiversity but also suggests these reptiles had a broader distribution than previously thought”. The species name "signus" derives from the Latin term for Montseny, "Mont-signus," meaning "signal mountain," reflecting the unique geological characteristics of the region.

The research also highlights significant variability in the dental forms recovered from capitosaurids, attributed to the species Calmasuchus acri, known exclusively from Catalonia and popularly referred to as “the Montseny capitosaur”. This amphibian species was described in 2011 from remains excavated at the La Mora site in Pla de la Calma (hence the name Calmasuchus). Initially, these animals were called “labyrinthodonts” due to the labyrinth-like internal structure of their teeth, but later they were reclassified as capitosaurians.

The study sheds light on the ecological interactions among these different animal groups. Capitosaurid amphibians (represented by Calmasuchus) likely acted as apex predators in freshwater environments, feeding primarily on fish and small terrestrial animals. Archosauromorphs, on the other hand, were medium to large carnivorous reptiles that preyed on a variety of tetrapods, including other archosauromorph reptiles and procolophonids such as Kapes. They may have also hunted larger prey like Calmasuchus specimens.

Image 2. Paleoenvironmental reconstruction of the La Mora site in the Montseny area approximately 242 million years ago. In the foreground, a large archosauromorph is depicted. At the lower right, the procolophonid Kapes signus is shown, while capitosaurs appear in the background. (Oscar Sanisidro / © Institut Català de Paleontologia Miquel Crusafont).

“Our analysis suggests capitosaurs played a crucial role as apex predators in aquatic environments”, commented co-author Eudald Mujal, researcher at the Staatliches Museum für Naturkunde Stuttgart and an associated researcher at ICP-CERCA. “Their feeding habits likely had a significant impact on the structure and dynamics of these early Mesozoic ecosystems”. Although fish were probably their main prey, they may have occasionally fed on other animals approaching the water's edge.

The study contributes to a better understanding of how ecosystems recovered following the great mass extinction at the end of the Permian —known as the Great Dying— the most catastrophic extinction event in Earth's history, even more devastating than the event that vanished the dinosaurs. It occurred about 252 million years ago, defining the end of the Permian period and the beginning of the Triassic. It is estimated that about 90-96% of marine species and 70% of terrestrial species perished, radically transforming life in all ecosystems.

Researchers emphasize the importance of continued sampling and paleontological studies in Montseny to better comprehend the complex ecosystems of the Middle Triassic. "This study is just the beginning", said Fortuny. "Much remains to be learned about life’s resilience and recovery after the Permian extinction. This article lays the groundwork for future investigations into these fascinating ecosystems."

In recent decades, the Montseny area has emerged as a key site for Middle Triassic ecosystems of equatorial Pangea, revealing a rich and diverse paleobiodiversity that goes far beyond the abundant capitosaur Calmasuchus acri. Research in this region of Catalonia has uncovered a remarkable variety of vertebrate fossils, turning Montseny into a window into complex Middle Triassic ecosystems with more intricate species dynamics than initially thought.

This research is supported by the Generalitat de Catalunya through the Department of Culture, which has provided financial backing for the projects "Evolution of ecosystems with vertebrate faunas from the Permian and Triassic of Catalonia" (ref. CLT009/18/00066) and "The End of an Era and the Rise of Modern Ecosystems: Vertebrate Faunas from the Carboniferous to the Triassic of Catalonia" (ref. ARQ001SOL2 - CLT0009_22_000020). The Generalitat has also contributed through the CERCA Program.

Main image: Life reconstruction of the new procolophonid reptile species Kapes signus described in the Montseny area. (Jesús Gamarra / © Institut Català de Paleontologia Miquel Crusafont)

Original article:

Riccetto, M., Mujal, E., Bolet, A., de Jaime-Soguero, C., De Esteban-Trivigno, S., & Fortuny, J. (2025). Tooth morphotypes shed light on the paleobiodiversity of Middle Triassic terrestrial vertebrate ecosystems from NE Iberian Peninsula (southwestern Europe). Rivista Italiana di Paleontologia e Stratigrafia, 131, 39-62. https://doi.org/10.54103/2039-4942/22340