Open Paleo

Amargatitanis

Apesteguía, 2007 a-MAHR-guh-tie-TAN-iss

Named after La Amarga Formation where the fossils were collected, combined with Greek 'titans' meaning 'giant'; meaning 'Amarga giant'

125.8–121.4 million years ago Barremian, Early Cretaceous
Early Cretaceous stages

Amargatitanis is a genus of dicraeosaurid sauropod dinosaur (a type of large, long-necked quadrupedal herbivorous dinosaur) from the Barremian-aged (Lower Cretaceous) La Amarga Formation of Neuquén, Argentina. It is known from a single, incomplete postcranial skeleton consisting of a partial hindlimb, ischium, and two vertebrae. These remains were unearthed by Argentine paleontologist José Bonaparte in 1983 during an expedition by the Museo Argentino de Ciencias Naturales and later described as a new genus and species, Amargatitanis macni by Sebastián Apesteguía. The genus name comes from the words Amarga, where the fossils were collected, and titanis meaning "titan". Its species name is in reference to the MACN (Museo Argentino de Ciencias Naturales), where the remains are stored.

Diagnosis

  1. Robust, wide and flat scapula developed in a single plane, with straight parallel anterior and posterior borders of the diaphysis and acromion in straight line with the diaphysis.
  2. Very short glenoid region with straight articulation for the coracoid and obtuse angle of coracoid articular surface with respect to the glenoid-scapular line; absence of scapular ventromedial process.
  3. Femoral fourth trochanter located at mid femur, with a prominent femoral head relative to a moderately developed distal region.
  4. High astragalus bearing a deep crescent-shaped fossa on the upper part of the tibial side of the posterior astragalar fossa, with two pairs of foramina.
  5. Posterior astragalar fossa fibular side bearing a deep concavity containing two foramina.

Species

Amargatitanis macni Apesteguía, 2007

Type species

Named for the Museo Argentino de Ciencias Naturales (MACN), where the holotype remains are stored.

Holotype
MACN PV N53 , Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’
Material
Six caudal vertebrae, a scapula, a femur, and one astragalus.
Horizon
Puesto Antigual Member, La Amarga Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
La Amarga (site 1), Neuquén, Argentina

References

  1. Apesteguía, S. (2007). The sauropod diversity of the La Amarga Formation (Barremian), Neuquén (Argentina). Gondwana Research 12(4): 533-546. Elsevier BV. doi:10.1016/j.gr.2007.04.007 apesteguía2007a
  2. Gallina, P. A. (2016). Reappraisal of the Early Cretaceous sauropod dinosaur Amargatitanis macni (Apesteguía, 2007), from northwestern Patagonia, Argentina. Cretaceous Research. Elsevier BV. doi:10.1016/j.cretres.2016.04.002

    Redefines the holotype as MACN PV N53 and places it in the Puesto Antigual Member.

    gallina2016a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b