This species was originally described in 2012 by paleontologists Federico L. Agnolín and Jorge I. Noriega, under the scientific name of Pterocnemia mesopotamica.[1] This generic taxon is mostly considered to be included in Rhea,[2][3] and P. mesopotamica was formally assigned to the genus Rhea by Tambussi, Degrange & De Mendoza (2023).[4]
- Holotype
The designated holotype is cataloged as: MACN-Pv 12743, and consists of the distal end of the right tarsometatarsus. It is deposited in the paleontological collections of the Argentine Museum of Natural Sciences "Bernardino Rivadavia" (MACN), located in the city of Buenos Aires, Argentina.[1] The following materials are also referred:
- 41-XII-13-928 (distal end of left tarsometatarsus);
- MACN-Pv 12735 (distal end of right tarsometatarsus);
- MACN-Pv 12737 (distal end of juvenile left tarsometatarsus);
- MACN-Pv 12740 (distal end of juvenile left tarsometatarsus without trochlea IV).
In the same location and horizon, fragmentary remains of a femur and a humerus were also found, identified as Rheidae indet.
- Type locality
The type locality is ravines of the Paraná Toma Vieja River, north of the city of Paraná, province of Entre Ríos, in the Mesopotamian region of northeast Argentina.
- Estimated characteristics
The remains found are thought to have belonged to a bird with a thin and small body, and a similar appearance to that of the short rhea or Patagonian rhea (R. pennata), and is characterized by the marked divergence of the tarsometatarsal trochlea.[1]
- Etymology
Etymologically, the specific term is a toponym that refers to the region from which the type specimen comes: Argentine Mesopotamia.[1]
