Open Paleo

Astigmasaura

Bellardini et al., 2025 ah-STIG-mah-SOR-uh

From compound Latin 'astigma' meaning 'without signs' and Ancient Greek 'saura' (feminine of sauros) meaning 'lizard'; references the type locality El Orejano, whose name refers to unmarked animals.

100.5–89.8 million years ago Cenomanian–Turonian, Late Cretaceous
Late Cretaceous stages

Astigmasaura is an extinct genus of rebbachisaurid sauropod dinosaurs from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, Astigmasaura genuflexa, known from an incomplete articulated skeleton.

Diagnosis

  1. Anterior caudal centra with prominent, expanded ventrolateral margins on the posterior articular surfaces
  2. Anterior caudal vertebrae with tall transverse processes (exceeding centrum height) positioned anterior to the neural spine in lateral view
  3. Asymmetric middle haemal arches with a straight anterior articular surface longer than the posterior one
  4. Pubis with an anterodorsally extended iliac peduncle, a wide elliptical obturator foramen (obturator-to-acetabular area ratio greater than 0.40), and a laminar, distally extended symphysis
  5. Femur with a prominent trochanteric shelf beneath the greater trochanter on the posterior surface of the proximal epiphysis, forming a posterior bulge in proximal view
  6. Pes with posteriorly expanded proximal halves of metatarsals II-IV, distolateral and medioproximal processes on proximal phalanges II-IV, and ungual phalanges bearing a longitudinal crest and fossa on the dorsal margin of the lateral surface

Species

Astigmasaura genuflexa Bellardini et al., 2025

Type species

From Medieval Latin, combining 'genu', meaning 'knee', and 'flecto', meaning 'to flex', translating roughly as 'kneeling', in reference to the discovery of the holotype with both hindlimbs angled backward.

Holotype
MAU-Pv-EO-629 , Museo Argentino Urquiza, Rincón de los Sauces
Material
Posterior half of an articulated postcranial skeleton: anterior and middle caudal vertebrae, haemal arches, both pubes and ischia, the ventral right ilium, both hind limbs, and pedal elements.
Horizon
lower Huincul Formation, Cenomanian–Turonian, Late Cretaceous , 100.5–89.8 million years ago
Locality
El Orejano, Neuquén, Argentina

References

  1. Bellardini, F.; Filippi, L. S.; Carballido, J. L.; Garrido, A. C.; Baiano, M. A. (2025). Side by side with titans: A new rebbachisaurid dinosaur from the Huincul Formation (upper Cenomanian) of Patagonia, Argentina. Cretaceous Research 176. Elsevier BV. doi:10.1016/j.cretres.2025.106188 bellardini2025a