Turiasaurians were first recognized as a distinctive group of non-neosauropod eusauropods 20 years ago, and this development allowed for a number of problematic tooth-based eusauropod taxa from Laurasia to be assigned to Turiasauria, such as Cardiodon, Neosodon, and Oplosaurus. However, it was not until the 2010s that turiasaurian taxa based on substantial remains were described from North America. A couple of papers published last month have filled additional gaps in the fossil record of turiasaurian sauropods from the Laurasian landmass, adding to a still burgeoning fossil record of Laurasian turiasaurians from outside the Iberian Peninsula. Therefore, I am giving an overview of these two developments in illuminating the biogeography of turiasaurians across the Northern Hemisphere during the Late Jurassic.
Turiasaurs from the Morrison Formation --- at last!
Since the days of the Bone Wars, nearly all sauropods described from the Morrison Formation have been assigned to Neosauropoda, but until now there was no indication of Turiasauria in this geologic unit. The paper by Foster et al. (2026) demonstrates that turiasaurians were present in the Morrison Formation and that there has been sampling bias with respect to sauropod cladistic diversity in the Morrison, especially when considering that Camarasaurus is the most abundant Morrison sauropod. Foster et al. provide an extensive table of the slender indices (SI) for the teeth catalogued under FHPR 18687 and the teeth of neosauropods known from the Morrison Formation, and the slender indices reported for FHPR 18687 may provide a window into the ancestral character states of diplodocoid teeth because Morrison diplodocoids have peg-shaped teeth. As a matter of fact, Foster et al. (2026) feel tempted to propose a working hypothesis that FHPR 18687 could pertain to Haplocanthosaurus because no craniodental material is known for that genus. Indeed, teeth with turiasaur-like morphologies have been found associated with new, undescribed specimens of Haplocanthosaurus sp. (Woodruff et al. 2025), but many cladistic analyses recover Haplocanthosaurus within Diplodocoidea (e.g. Whitlock 2011; Tschopp et al. 2015), possibly implying convergence between the teeth of turiasaurians and those of Haplocanthosaurus or the presence of turiasaur-like teeth in basal diplodocoids.
The first turiasaurian from Asia
The known fossil record of eusauropods from the Middle to Late Jurassic of East Asia is dominated by mamenchisaurids but also includes a handful of macronarians (Lingwulong is the only diplodocoid known from the Jurassic of East Asia at the moment), providing a window into eusauropod evolution in East Asia from the Bajocian to Tithonian interval. Now, the description of the new taxon Yantaloong lini from the Middle Jurassic Zhanghe Formation fills a gap in the fossil record of Middle Jurassic non-neosauropod eusauropods from East Asia by demonstrating that turiasaurians were beginning to achieve a global distribution in the Middle Jurassic. The East Asian Isolation Hypothesis that was once used to explain the predominance of mamenchisaurids among East Asian sauropods from the Middle-Late Jurassic has been refuted by the assignment of Dashanpusaurus and Yuzhoulong to Macronaria, and there is evidence of niche partitioning among Middle Jurassic eusauropods from East Asia (Ren et al. 2022).
Although the holotype of Yantaloong lini is very limited, some cladistic analyses by Zhang et al. (2026) recovering Yantaloong as a member of Turiasauria find this taxon to be more closely related to the Gondwanan taxa Atlasaurus, Jobaria, and Lapparentosaurus, hinting at a Gondwanan origin for some Laurasian turiasaurians.
References:
Foster, J.R., Woodruff, C., and Royo-Torres, R., 2026. The first evidence of Turiasauria (Sauropoda) in the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 102: 267–282.
Ren, X.X., Jiang, S., Wang, X.R., Peng, G.Z., Ye, Y., King, L., and You, H.L., 2022. Osteology of Dashanpusaurus dongi (Sauropoda: Macronaria) and new evolutionary evidence from Middle Jurassic Chinese sauropods. Journal of Systematic Palaeontology. 20 (1). 2132886. doi:10.1080/14772019.2022.2132886.
015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3:e857 https://doi.org/10.7717/peerj.857
Woodruff, D.C., Barrett, P.M., Ouarhache, D., El Khanchoufi, A., Boumir, K., Ech-Charay, K., Oussou, A., Butler, R.J., Wills, S., Meade, L., Smith, M., and Maidment, S.C.R. 2025. Teeth from the Middle Jurassic of Morocco reveal the oldest turiasaurian sauropods from Africa. Acta Palaeontologica Polonica 70 (3): 411–420.
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., and You, H.-L., 2026. The first turiasaurian sauropod (Dinosauria: Eusauropoda) from East Asia. Zoological Journal of the Linnean Society 206 (2): zlaf201. doi:10.1093/zoolinnean/zlaf201.
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