Lourinhanosaurus is a genus of theropod dinosaur that lived during the Late Jurassic period (Kimmeridgian stage, approximately 155–152 million years ago). Fossils attributed to this genus have been recovered from the Lourinhã Formation in the town of Lourinhã, western Portugal. The type and only species, Lourinhanosaurus antunesi, was formally described in 1999 by José Bonaparte and Octávio Mateus.
Discovery and Naming
- Holotype: The holotype specimen (designated ML 219) consists of a partial postcranial skeleton, including cervical and dorsal vertebrae, ribs, portions of the pelvis, and limb fragments. It was discovered in the early 1990s during systematic excavations of the Lourinhã Formation.
- Etymology: The generic name combines “Lourinhã,” the locality of the find, with the Greek suffix “-saurus” (meaning “lizard”). The specific epithet antunesi honors Portuguese paleontologist Miguel Antunes, who contributed to the study of Portuguese Jurassic vertebrates.
Description
- Size: Based on skeletal proportions, Lourinhanosaurus is estimated to have measured approximately 5–6 metres (16–20 ft) in length and weighed around 400–600 kg.
- Skeleton: The available material indicates a moderately robust build typical of basal tetanuran theropods. Cervical vertebrae show elongated neural arches, while dorsal vertebrae possess well‑developed hyposphene–hypantrum articulations, suggesting a sturdy torso. Limb elements suggest a bipedal posture with functional grasping forelimbs.
- Diagnostic Features: Distinctive characteristics include a combination of vertebral laminae patterns and specific pelvic morphology that differentiate it from contemporaneous European theropods such as Allosaurus and Torvosaurus.
Classification
- Higher Taxonomy: Lourinhanosaurus is placed within the clade Tetanurae, a major subgroup of theropod dinosaurs. Phylogenetic analyses have variably positioned it within Megalosauridae or as a basal member of a broader clade of carnosaurs. Consensus indicates it is a basal tetanuran, but its precise relationships remain unsettled due to the fragmentary nature of the material.
- Related Taxa: Comparative studies have noted affinities with other Late Jurassic European theropods, including Megalosaurus, Torvosaurus, and the Portuguese taxon Allosaurus europaeus.
Paleobiology
- Ecology: The Lourinhã Formation represents a coastal to fluvial environment with abundant vegetation and a diverse vertebrate assemblage, including sauropods (e.g., Dinheirosaurus), ornithopods, and other theropods. Lourinhanosaurus likely occupied a mid‑top predator niche, preying upon smaller vertebrates and possibly scavenging larger carcasses.
- Behavior: Limb morphology suggests that it was capable of rapid bipedal locomotion, while its robust forelimbs may have been used for grasping prey.
Historical Significance
Lourinhanosaurus contributes to the understanding of Jurassic theropod diversity in the Iberian Peninsula and provides evidence for faunal connections between western European and Gondwanan dinosaur assemblages during the Late Jurassic.
References
- Bonaparte, J. F., & Mateus, O. (1999). Lourinhanosaurus antunesi, a new theropod dinosaur from the Upper Jurassic of Portugal. Proceedings of the 20th International Geological Congress, 3, 53–60.
- Subsequent phylogenetic studies (e.g., Benson et al., 2010; Rauhut & Pol, 2019) discuss the placement of Lourinhanosaurus within basal tetanuran theropods.