Open Paleo

Lapparentosaurus

Bonaparte, 1986 la-pah-RENT-o-SAWR-us

Named in honor of French paleontologist Albert-Félix de Lapparent, combined with Greek 'sauros' (lizard); meaning 'Lapparent's lizard'

168.2–165.3 million years ago Bathonian, Middle Jurassic
Middle Jurassic stages

Lapparentosaurus is a genus of sauropod dinosaur from the Middle Jurassic. Its fossils were found in Madagascar (Isalo III Formation). It contains one species, Lapparentosaurus madagascariensis. The genus and species were named by José Bonaparte in 1986. The classification of Lapparentosaurus is controversial, as it exhibits a combination of characteristics of basal sauropods and titanosauriforms.

Under dispute

Lapparentosaurus was erected within Cetiosauridae (Bonaparte, 1986), but subsequent analyses have placed it in almost every other position available: within Brachiosauridae (Upchurch, 1998), as Titanosauriformes incertae sedis and too unstable to retain in the consensus (Upchurch and colleagues, 2004), as a non-neosauropod eusauropod in all analyses (Mannion and colleagues, 2013), and within a broadened Turiasauria alongside Jobaria and Atlasaurus (Moore and colleagues, 2020; Zhang and colleagues, 2026). Raveloson and colleagues (2019) argue for a cetiosaurid position from newly described femoral and neural spine material, but from anatomical comparison rather than a phylogenetic analysis. A position outside Neosauropoda is well supported; the finer placement is not, and the type material is juvenile.

Diagnosis

  1. Posterior dorsal neural spines low and laterally flat, without divergent (tetraradiate) laminae
  2. Neural arch of the posterior dorsals low, with a short distance between the zygapophyses and the centrum (poor dorsoventral development)

Species

Lapparentosaurus madagascariensis Bonaparte, 1986

Type species

Named for Madagascar, the island nation where the fossil material was discovered in the Isalo III Formation.

Holotype
MNHN.F.MAA91, MNHN.F.MAA92 , Muséum national d'Histoire naturelle
Material
Two associated neural arches of posterior dorsal vertebrae, with broken diapophyses.
Horizon
Isalo III Formation, Bathonian, Middle Jurassic , 168.2–165.3 million years ago
Locality
Andranomamy, Mahajanga, Madagascar

References

  1. Bonaparte, J. F. (1986). The early radiation and phylogenetic relationships of the Jurassic sauropod dinosaurs, based on vertebral anatomy. The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic-Jurassic Boundary 247-258. Cambridge University Press, Cambridge. bonaparte1986a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026b
  3. Zhang, X. Q.; Wang, Y. M.; Wang, Z. J.; Wang, Y. C.; Wang, T.; Wang, G. F.; Zou, Y.; Dong, Q. X.; Su, X.; Jiang, H.; Wang, Y. J.; You, H. L. (2026). The first turiasaurian sauropod (Dinosauria: Eusauropoda) from East Asia. Zoological Journal of the Linnean Society 206(2): zlaf201. Oxford University Press. doi:10.1093/zoolinnean/zlaf201

    Places Lapparentosaurus within Turiasauria alongside Jobaria and Atlasaurus in new phylogenetic analysis

    zhang2026a
  4. Raveloson, M. L. T.; Clark, N. D. L.; Rasoamiaramana, A. H. (2019). New Information on the Madagascan Middle Jurassic Sauropod Lapparentosaurus madagascariensis. Geosciences 9(12): 498. doi:10.3390/geosciences9120498

    Newly described femoral and neural spine material argued, by anatomical comparison rather than phylogenetic analysis, to support a cetiosaurid position.

    raveloson2019a
  5. Moore, A. J.; Upchurch, P.; Barrett, P. M.; Clark, J. M.; Xu, X. (2020). Osteology of Klamelisaurus gobiensis (Dinosauria, Eusauropoda) and the evolutionary history of Middle-Late Jurassic Chinese sauropods. Journal of Systematic Palaeontology 18(16): 1299-1393. doi:10.1080/14772019.2020.1759706

    Implied-weights and Bayesian analyses recover Lapparentosaurus as a turiasaurian outside Neosauropoda.

    moore2020a
  6. Mannion, P. D.; Upchurch, P.; Barnes, R. N.; Mateus, O. (2013). Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society 168(1): 98-206. Oxford University Press (OUP). doi:10.1111/zoj.12029

    Found no support for a titanosauriform position, recovering Lapparentosaurus as a non-neosauropod eusauropod in all analyses.

    mannion2013a
  7. Upchurch, P.; Barrett, P. M.; Dodson, P. (2004). Sauropoda. The Dinosauria, Second Edition (Weishampel, D. B.; Dodson, P.; Osmólska, H., eds.) 259-322. University of California Press, Berkeley.

    Recovered Lapparentosaurus as Titanosauriformes incertae sedis and deleted it from the consensus tree as an unstable taxon.

    upchurch2004a
  8. Upchurch, P. M. (1998). The phylogenetic relationships of sauropod dinosaurs. Zoological Journal of the Linnean Society 124: 43-103. doi:10.1111/j.1096-3642.1998.tb00569.x

    Phylogenetic analysis of sauropods placed Lapparentosaurus within Brachiosauridae.

    upchurch1998a
  9. Läng, É. (2008). Les Cétiosaures (Dinosauria, Sauropoda) et les sauropodes du Jurassique moyen: révision systématique, nouvelles découvertes et implications phylogénétiques. Museum National D'Histoire Naturelle.

    Recovered Lapparentosaurus within a restricted or paraphyletic Cetiosauridae.

    läng2008a