Open Paleo

Tambatitanis

Saegusa & Ikeda, 2014 TAM-buh-TIE-tan-is

Named for Tamba (now Tamba-Sasayama), the city in Hyōgo Prefecture, Japan, where the fossils were found, combined with Ancient Greek 'titanis' meaning 'titan' or 'giant'; meaning 'Tamba giant.'

113.2–100.5 million years ago Albian, Early Cretaceous
Early Cretaceous stages

Tambatitanis is an extinct genus of titanosauriform, possibly titanosaurian, sauropod dinosaur from the Early Cretaceous-aged (early Albian) Ohyamashimo Formation of the Sasayama Group. It is known from a single species, Tambatitanis amicitiae, known from a partial skeleton.

Under dispute

Tambatitanis was preliminarily placed within Euhelopodidae by its describers, who nonetheless noted titanosaur-like braincase features (Saegusa and Ikeda, 2014). A more recent analysis instead recovered it within Titanosauria rather than as a euhelopodid, though only with weak support (Mo and colleagues, 2023).

Diagnosis

  1. Postzygapophysis and neural spine summit of anterior caudal vertebrae located beyond posterior centrum border
  2. Anterior caudal vertebrae neural spine curved strongly anteriorly, bow-shaped in lateral view
  3. Neural spine summit expanded hemispherical with anterior face excavated by deep narrow spinoprezygapophyseal fossa
  4. Transverse processes of anterior caudal vertebrae short and L-shaped
  5. Anterior chevron longest among sauropods in proportion to body size
  6. Distal ends of anterior chevrons rod-shaped
  7. Distal ends of mid chevrons transversely thin, anteroposteriorly long without cranial process
  8. Paroccipital process dorsal border short mediolaterally and V-shaped in posterior view

Species

Tambatitanis amicitiae Saegusa & Ikeda, 2014

Type species

From Latin 'amicitia' meaning 'friendship', referring to the friendship between the two discoverers of the holotype, Shigeru Murakami and Kiyoshi Adachi.

Holotype
MNHAH D-1029280 , Museum of Nature and Human Activities
Material
Partial skeleton: teeth, braincase, dentary, atlas, cervical vertebra, dorsal vertebrae, dorsal ribs, sacral ribs, sacral spine, pubis, ilium, caudal vertebrae, chevrons
Horizon
Ohyamashimo Formation, Albian, Early Cretaceous , 113.2–100.5 million years ago
Locality
Kamitaki Quarry, Hyōgo, Japan

References

  1. Saegusa, H.; Ikeda, T. (2014). A new titanosauriform sauropod (Dinosauria: Saurischia) from the Lower Cretaceous of Hyogo, Japan. Zootaxa 3848(1). Magnolia Press. doi:10.11646/zootaxa.3848.1.1 saegusa2014a
  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. Mo, J.; Ma, F.; Yu, Y.; Xu, X. (2023). A new titanosauriform sauropod with an unusual tail from the Lower Cretaceous of northeastern China. Cretaceous Research 144. Elsevier BV. doi:10.1016/j.cretres.2022.105449

    Phylogenetic analysis recovered Tambatitanis within Titanosauria rather than as a euhelopodid titanosauriform, with weak support.

    mo2023b