Open Paleo

Tonganosaurus

Li et al., 2010 toon-GAH-no-SOR-us

Named for the town of Tong'an in Sichuan Province, China, near where it was found, plus Greek sauros ('lizard')

Tonganosaurus is a genus of mamenchisaurid sauropod dinosaur, similar to Omeisaurus. It is known from one specimen consisting of twenty vertebrae, a front limb and pectoral girdle, and a complete hind limb with partial hip. It was discovered in the Yimen Formation, China. The horizon of the specimen and the age of the Yimen Formation is controversial. The formation has been divided into three levels, and Tonganosaurus comes from its middle to upper part. Tonganosaurus is the oldest known member of the mamenchisaurids, being almost 15 million years older than the next-oldest members of the group. It was first named by Li Kui, Yang Chun-Yan, Liu Jian, and Wang Zheng-Xin in 2010, and the type species is Tonganosaurus hei.

Diagnosis

  1. All presacral vertebrae with well-developed lateral fossae, large and deep but lacking internal septa
  2. Cervical vertebrae slender with low and anteroposteriorly elongated neural spines and arches
  3. Pleurocoel and fossa structures of posterior cervical and dorsal vertebrae well developed
  4. Anterior dorsal vertebrae opisthocoelous, middle dorsals platycoelous, posterior dorsals amphicoelous
  5. Vertebral bone texture compact and non-camerate
  6. Forelimb-to-hindlimb ratio 0.80
  7. Femur straight and robust with well-developed fourth trochanter
  8. Tibiae straight and robust, length equal to 0.75 times femur length

Species

Tonganosaurus hei Li et al., 2010

Type species

Named in honor of Mr. He Xinlu, who has long been dedicated to supporting dinosaur research.

Holotype
MCDUT 14454 , Chengdu University of Technology
Material
Skeleton of not entirely complete adult sauropod with approximately 20 vertebrae, complete right pectoral girdle and right forelimb, distal end of left scapula, complete left and right clavicles, both ends of left femur, complete right hindlimb, and scattered dorsal neural spines, ribs, metatarsals, and unguals
Horizon
Yimen Formation, Early Jurassic
Locality
Tong'an, Sichuan, China Li and colleagues (2010) place the site, from field section tracing and the 1:200,000 geological map, in "下侏罗统益门组中上部，岩性为紫红色粉砂质泥岩" (the middle to upper part of the Lower Jurassic Yimen Formation, purplish-red silty mudstone, translated).

References

  1. Li, K.; Yang, C. Y.; Liu, J.; Wang, Z. X. (2010). [A new sauropod from the Lower Jurassic of Huili, Sichuan, China]. Vertebrata PalAsiatica 48(3): 185-202. li2010a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the mass and hip height estimates, and the appearance features.

    jones2026b