Open Paleo

Tethyshadros

Dalla Vecchia, 2009 teth-eez-HAD-ros

Named after the ancient Tethys Sea (whose remnant waters covered the region), combined with Greek hadros, "thick" or "stout" (root of Hadrosauridae) — means "Tethyan hadrosauroid"

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Tethyshadros is a genus of hadrosauroid dinosaur from the Late Cretaceous (Campanian) Lipica Formation (previously thought to come from the younger informal "Liburnia Formation") of Trieste, Italy. The type and only species is T. insularis.

Under dispute

Tethyshadros insularis is recovered as a derived non-hadrosaurid hadrosauromorph in recent analyses. Several recover it as the sister taxon of Telmatosaurus (Xing and colleagues, 2014; Lockwood and colleagues, 2021); others place the two at successive nodes below Hadrosauridae (Prieto-Márquez and colleagues, 2013), and Prieto-Márquez and Carrera Farias (2021) pair it with Fylax instead. Magyar and colleagues (2026) name the Telmatosaurus–Tethyshadros group, with Kryptohadros, as the clade Telmatosauridae.

Diagnosis

  1. Skull large (1.60-1.65 times humeral length) and elongate (length:height ratio 2.6)
  2. Premaxillary denticles very large, slender and pointed
  3. Small paired crests in caudal part of parietals
  4. Neural spines of proximal caudal vertebrae 1-6 hatchet-shaped
  5. Long whip-like mid- to distal tail with elongated centra (2.4-3.4 times longer than high)
  6. Tibia considerably longer than femur

Species

Tethyshadros insularis Dalla Vecchia, 2009

Type species

From Latin 'insularis' meaning 'insular' or 'of the island', referring to the European Archipelago island on which the species lived during the Late Cretaceous.

Holotype
SC 57021 , Museo Civico di Storia Naturale di Trieste
Material
Complete and articulated skeleton with skull, most postcranial skeleton.
Horizon
lower Liburnian Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Villaggio del Pescatore, Trieste, Italy

Notable specimens

  • “Bruno”

    SC 57247 Museo Civico di Storia Naturale di Trieste complementary

    Extensive referred skeleton with a complete skull and postcranium found at Villaggio del Pescatore; 15-20% larger than the subadult holotype Antonio and assessed as an adult, showing maturity features such as a more robust skull and stouter proportions. Formally described in 2021.

    Dalla Vecchia (2020)Chiarenza et al. (2021)

References

  1. Dalla Vecchia, F. M. (2020). The unusual tail of Tethyshadros insularis (Dinosauria, Hadrosauroidea) from the Adriatic island of the European archipelago. Rivista Italiana di Paleontologia e Stratigrafia 126(3). doi:10.13130/2039-4942/14075 dallavecchia2020a
  2. Chiarenza, A. A.; Fabbri, M.; Consorti, L.; Muscioni, M.; Evans, D. C.; Cantalapiedra, J. L.; Fanti, F. (2021). An Italian dinosaur Lagerstätte reveals the tempo and mode of hadrosauriform body size evolution. Scientific Reports 11(1): 23295. Springer Science and Business Media LLC. doi:10.1038/s41598-021-02490-x chiarenza2021a
  3. Dalla Vecchia, F. M. (2009). Tethyshadros insularis, a new hadrosauroid dinosaur (Ornithischia) from the Upper Cretaceous of Italy. Journal of Vertebrate Paleontology 29(4): 1100-1116. doi:10.1671/039.029.0428 dallavecchia2009a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026a
  5. Magyar, J.; Ősi, A.; Csiki-Sava, Z.; Budai, S.; Botfalvai, G. (2026). New early Maastrichtian 'duck-billed' dinosaur from Hațeg Basin (Densuș-Ciula Formation, Romania) documents an endemic clade of non-hadrosaurid hadrosauroids in the south-eastern Late Cretaceous European Archipelago. Journal of Systematic Palaeontology 24(1): 2607800. Informa UK Limited. doi:10.1080/14772019.2025.2607800

    Recovered Tethyshadros as a derived hadrosauromorph within the newly named clade Telmatosauridae.

    magyar2026a
  6. Xing, H.; Wang, D.; Han, F.; Sullivan, C.; Ma, Q.; He, Y.; Hone, D. W. E.; Yan, R.; Du, F.; Xu, X. (2014). A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) with Transitional Features from the Late Cretaceous of Henan Province, China. PLoS ONE 9(6): e98821. Public Library of Science (PLoS). doi:10.1371/journal.pone.0098821

    Recovered Tethyshadros and Telmatosaurus as sister taxa.

    xing2014a
  7. Lockwood, J. A. F.; Martill, D. M.; Maidment, S. C. R. (2021). A new hadrosauriform dinosaur from the Wessex Formation, Wealden Group (Early Cretaceous), of the Isle of Wight, southern England. Journal of Systematic Palaeontology 19(12): 847-888. Informa UK Limited. doi:10.1080/14772019.2021.1978005

    Recovered Tethyshadros and Telmatosaurus as sister taxa, outside Hadrosauridae.

    lockwood2021a
  8. Prieto-Márquez, A.; Dalla Vecchia, F. M.; Gaete, R.; Galobart, À. (2013). Diversity, Relationships, and Biogeography of the Lambeosaurine Dinosaurs from the European Archipelago, with Description of the New Aralosaurin Canardia garonnensis. PLoS ONE 8(7): e69835. Public Library of Science (PLoS). doi:10.1371/journal.pone.0069835

    Recovered Telmatosaurus and Tethyshadros at successive nodes below Hadrosauridae.

    prieto-márquez2013a
  9. Prieto-Márquez, A.; Carrera Farias, M. (2021). The late-surviving early diverging Ibero-Armorican 'duck-billed' dinosaur Fylax and the role of the Late Cretaceous European Archipelago in hadrosauroid biogeography. Acta Palaeontologica Polonica 66. Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). doi:10.4202/app.00821.2020

    Described Fylax and recovered it as the sister taxon of Tethyshadros.

    prieto-márquez2021a