Paleontologists have discovered the skeletal remains of an entirely new, yet-to-be-named species of massopodan sauropodomorph dinosaur in the Klettgau Formation in Canton Aargau, Switzerland.
Articulated skull of the new massopodan sauropodomorph dinosaur in right lateral view. Scale bars – 5 cm. Image credit: Lania et al., doi: 10.1186/s13358-025-00373-6.
The newly-discovered fossil dates back to the Norian age of the Late Triassic epoch, some 206 million years ago.
It belongs to a previously unknown member of Massopoda, a large group of sauropodomorph dinosaurs that lived during the Late Triassic to Late Cretaceous epochs.
“Among the Mesozoic terrestrial vertebrate groups, Sauropodomorpha represents one of the most successful dinosaurian clades, as it became one of the most abundant and dominant herbivore components of both the Late Triassic and the Jurassic continental paleoecosystems with an almost global distribution, spatially spanning from Antarctica to Greenland,” said Dr. Alessandro Lania from the Rheinische Friedrich-Wilhelms-Universität Bonn and his colleagues from Switzerland.
“The origin of sauropodomorphs dates back to the early Late Triassic of Gondwanan continents with the oldest representatives discovered in Brazil, Argentina, southern Africa, and North America.”
“Based on the South American fossil record, which provides one of the most comprehensive understandings of the early evolution of Sauropodomorpha, a rapid radiation and diversification occurred in a timeframe of approximately 30 million years, shifting from a limited number of lineages characterized by a small body size, bipedal locomotion and carnivorous/faunivorous dietary habits to a plethora of new sauropodomorphs during the Norian-Rhaetian accounting for medium-to-large size body plans, onset of quadrupedality and acquisition of herbivorous diet.”
“Additionally, this dramatic increase in the sauropodomorph paleobiodiversity of southern Pangea at Norian times is further attested by the emergence of new main lineages, such as Massopoda and Sauropodiformes, as well as by a notable divergence in the morphological disparity, which is consequently reflected in an expansion of the occupied morphospace given the development of novel anatomical features.”
The partially complete skeleton of the new massopodan sauropodomorph was found in 2013 in the uppermost fossiliferous horizon of the Gruhalde Member (Klettgau Formation) in the Gruhalde Quarry in Frick, Canton Aargau, Switzerland.
“The Klettgau Formation is one of the most extensive stratigraphic successions of the Late Triassic in Europe, consisting of a lithologically heterogenous series deposited over a prolonged timeframe of 26-30 million years, from the Early Carnian to the Late Rhaetian,” the paleontologists said.
“Outcropping in many localities across Switzerland, the Klettgau Formation records a non-continuous sequence of variegated playa sediments with fluvial and marine influence, depicting various lateral paleoenvironmental shifts over the entire stratigraphic section.”
The new specimen represents the first non-Plateosaurus sauropodomorph from the Canton Aargau and the fourth Late Triassic non-sauropodan sauropodomorph of Switzerland.
“The osteological investigation coupled with morphological comparisons unraveled a mosaic craniomandibular anatomy that combines features typical of non-massopodan plateosaurians and massopodan sauropodomorphs, a condition shared with the mid-to-late Norian massospondylid Coloradisaurus brevis from Argentina,” the researchers said.
According to the authors, this dinosaur is the first non-sauropodiform massopodan from Laurasia.
“Remarkably, the resulting macroevolutionary scenario opens up a plausible hypothesis supporting a European origin for the Early Jurassic massopodans from Asia during the Late Triassic, although more evidence is required to corroborate it,” they said.
“Moreover, the fossil increases both the craniodental disparity and the paleobiodiversity of Norian sauropodomorphs from Laurasia, with the latter being comparable to those from Gondwana, especially South America and Africa.”
The team’s paper was published this month in the Swiss Journal of Palaeontology.
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A. Lania et al. 2025. Craniomandibular osteology of a new massopodan sauropodomorph (Dinosauria: Sauropodomorpha) from the Late Triassic (latest Norian) of Canton Aargau, Switzerland. Swiss J Palaeontol 144, 39; doi: 10.1186/s13358-025-00373-6