Paleontologists have unearthed the fossilized bones of one of the smallest sauropod dinosaurs that lived during the Late Triassic period in southern Brazil, providing new insights into the development and physiology of early dinosaurs.
Massospondylus carinatusa type of small sauropod dinosaur that lived in the early Jurassic period of southern Africa. Image credit: Nobu Tamura, http://spinops.blogspot.com / Patty Jansen / Sci.News.
Dr. Luciano Artemio Real of the University of Sudoeste da Bahia and his colleagues collected new dinosaur material from the Cerro da Aremoa outcrop in southern Brazil.
“The Cerro da Aremoa outcrop is an important geological and zoological record of the Santa María Supersequence in central Rio Grande do Sul,” they explained.
The material dates back to the Carnian period of the late Triassic period, 237 to 227 million years ago.
It consists of small bones, all less than 5.7 cm (2.2 inches) long, including part of the humerus, metatarsals, nail phalanges, neural arch, and vertebral center.
The team’s phylogenetic and anatomical analyzes placed the specimen firmly within the basal sauropod clade.
“This specimen is an important juvenile dinosaur,” the paleontologists said.
“A combined analysis of its morphology, bone histology, and phylogeny indicates that this is a basal sauropod from the Brazilian Triassic.”
Unlike later sauropods, which achieved gigantic body size, this early form was likely much smaller in stature when it was still in its developmental stages.
Importantly, the bone microstructure revealed evidence of at least one complete cycle of growth interruption with a line of growth arrest, suggesting that this individual experienced a developmental pause early in life.
This pattern suggests that early sauropods may have adopted flexible growth strategies despite their small body size, a finding that may help explain the later emergence of gigantism in this group.
“The observed characteristics suggest that the individuals are still developing, have already experienced the first growth arrest and are in the middle of the second cycle,” the researchers said.
“These analyzes suggest ontogenetic characteristics of juvenile sauropods with a single growth arrest.”
“Our findings provide evidence for a new growth strategy in the early evolution of this group, leading to the emergence of small dinosaurs in the Triassic.”
of findings To be published in the April 2026 issue of the journal paleo world.
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Leomir Santos Campos others. 2026. A new small basal sauropod (Dinosauria: Saurischia) discovered from the Santa Maria supersequence in the Upper Triassic of southern Brazil. paleo world 35 (2): 201064;doi: 10.1016/j.palwor.2025.201064