Paleontologists have discovered fossilized remains of one of the smallest sauropod dinosaurs from the Late Triassic period in southern Brazil. This remarkable find sheds light on early dinosaur development and physiology.
Massospondylus carinatus, a small sauropod dinosaur from the Early Jurassic of southern Africa. Image credit: Nobu Tamura, http://spinops.blogspot.com / Patty Jansen / Sci.News.
Dr. Luciano Artemio Real from the University of Sudoeste da Bahia and his team collected significant dinosaur material from the Cerro da Aremoa outcrop located in southern Brazil.
The Cerro da Aremoa outcrop serves as a crucial geological and zoological record within the Santa María Supersequence in central Rio Grande do Sul.
This recently recovered material dates to the Carnian period of the Late Triassic, approximately 237 to 227 million years ago.
The fossilized remains include small bones, each measuring less than 5.7 cm (2.2 inches), comprising parts of the humerus, metatarsals, nail phalanges, neural arch, and vertebral center.
A thorough phylogenetic and anatomical analysis positioned the specimen clearly within the basal sauropod clade.
“This specimen is a significant juvenile dinosaur,” noted the paleontologists.
“A combined analysis of its morphology, bone histology, and phylogenetic data indicates that it represents a basal sauropod from the Brazilian Triassic.”
Unlike later giant sauropods, this early version likely maintained a much smaller size during its developmental phases.
Notably, the bone microstructure exhibited signs of at least one complete growth interruption cycle, indicated by a line of growth arrest. This suggests that the dinosaur experienced a developmental pause early in its life, hinting at the potential for flexible growth strategies within early sauropods.
These findings may provide insights into the eventual gigantism characteristic of later sauropod species.
“These observed traits indicate that the individuals, still in development, have experienced their first growth arrest and are in the midst of a second cycle,” researchers commented.
“Our analyses suggest ontogenetic features typical of juvenile sauropods exhibiting a single growth arrest.”
“Our research unveils a new growth strategy in the early evolution of sauropods, illuminating the origins of small dinosaurs during the Triassic period.”
The full findings will appear in the April 2026 edition of the journal Paleo World.
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Leomir Santos Campos et al. 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
Source: www.sci.news
