Open Paleo

Unenlagia

Novas & Puerta, 1997 oon-en-LAHG-ee-a

From Mapuche 'unum' meaning 'bird' and 'llag' meaning 'half', meaning 'half-bird', reflecting its interpreted transitional position between birds and basal theropods.

93.9–85.7 million years ago Turonian–Coniacian, Late Cretaceous
Late Cretaceous stages

Unenlagia is a genus of unenlagiine theropod dinosaur that lived in South America during the Late Cretaceous period. The genus Unenlagia has been assigned two species: U. comahuensis, the type species described by Novas and Puerta in 1997, and U. paynemili, described by Calvo and colleagues in 2004.

Diagnosis

  1. Tall neural spines in posterior dorsals and anterior sacral vertebrae, nearly twice height of centrum
  2. Deep lateral pits in base of neural spines of posterior dorsals and anterior sacrals
  3. Twisted scapular shaft with dorsal-facing external surface
  4. Inflected dorsal margin of postacetabular iliac blade
  5. Laterally oriented humeral articulation of scapula (previously unreported in non-avian dinosaurs)
  6. Laterally oriented glenoid cavity enabling avian-style forelimb folding and elevation

Species (2)

Unenlagia comahuensis Novas & Puerta, 1997

Type species

Named for the Comahue region (northwestern Patagonia), where the type locality lies.

Holotype
MCF-PVPH 78 , Museo ‘Carmen Funes’, Plaza Huincul
Material
Three presacral (8th, 10th, 13th dorsal) vertebrae, sacrum, dorsal ribs, two proximal haemal arches, left scapula, incomplete humerus, ilia, pubes, right ischium, right femur, and left tibia.
Horizon
Portezuelo Formation, Turonian–Coniacian, Late Cretaceous , 93.9–85.7 million years ago
Locality
Sierra del Portezuelo, Neuquén, Argentina

Unenlagia paynemili Calvo et al., 2004

Honors Maximino Paynemil, chief of the Paynemil community near the Futalognko site.

Holotype
MUCPv-349 , Universidad Nacional del Comahue
Material
Left humerus (217 mm) and left pubis (267 mm) of a single individual.
Horizon
upper Portezuelo Formation, Turonian–Coniacian, Late Cretaceous , 93.9–85.7 million years ago
Locality
Futalognko site, Neuquén, Argentina
Diagnosis
  1. More gracile long bones
  2. Deltopectoral crest meeting the humeral shaft at about 116 degrees (about 140 degrees in U. comahuensis)
  3. Small anterior process on the distal end of the pubis (absent in U. comahuensis)
  4. Postacetabular blade of the ilium broader and rounded distally, with a shallower brevis fossa

References

  1. Calvo, J. O.; Porfiri, J. D.; Kellner, A. W. A. (2004). On a new maniraptoran dinosaur (Theropoda) from the Upper Cretaceous of Neuquén, Patagonia, Argentina. Arquivos do Museu Nacional 62(4): 549-566. Museu Nacional, Universidade Federal do Rio de Janeiro. calvo2004c
  2. Novas, F. E.; Puerta, P. F. (1997). New evidence concerning avian origins from the Late Cretaceous of Patagonia. Nature 387(6631): 390-392. Springer Science and Business Media LLC. doi:10.1038/387390a0 novas1997a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c