Open Paleo

Heptasteornis

Harrison & Walker, 1975 hep-tas-tee-OR-nis Nomen dubium

From Greek 'hepta' meaning 'seven', 'asty' meaning 'city', and 'ornis' meaning 'bird', referencing the Latin 'septum urbium' / German 'Siebenbürgen' ('seven cities/castles') — historical names for the Transylvanian region.

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Heptasteornis is a dubious genus of alvarezsaurid dinosaur from the Late Cretaceous. The type (and only known) species is Heptasteornis andrewsi, described as a presumed gigantic prehistoric owl in 1975. It was previously included in Elopteryx nopcsai and indeed the holotypes of both species were believed to be from the same individual as they were discovered, and initially were assigned the same specimen number. This appears to be in error however.

Under dispute

Heptasteornis andrewsi, from the Maastrichtian of Romania, is based on a distal tibiotarsus that Naish and Dyke (2004) identified as the first European alvarezsaurid on the basis of an alvarezsaurid-type astragalar notch; they nonetheless regarded the genus as a nomen dubium for lack of distinguishing autapomorphies. Hartman and colleagues (2019) recover it as an alvarezsaurid, and Meso and colleagues (2024) find it unstable and prune it; Csiki and Grigorescu (1998) had regarded the tibiotarsi as possibly from a non-maniraptoran tetanuran.

Species

Heptasteornis andrewsi Harrison & Walker, 1975 Nomen dubium

Type species

Named for C. W. Andrews, who named the related genus Elopteryx, with the epithet honoring Andrews as the scientific authority behind the broader Transylvanian bird material.

Holotype
BMNH A4359 , Natural History Museum
Material
Distal end of a left tibiotarsus.
Notes
Harrison and Walker (1975) designate a second distal left tibiotarsus, A 1528, as the paratype.
Horizon
Sânpetru Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Sibișel Valley, Hunedoara, Romania Harrison and Walker (1975) record only that Nopcsa presented the holotype in 1913. Csiki and Grigorescu (1998) traced it back to Sibișel Valley through Andrews.

References

  1. Harrison, C. J. O.; Walker, C. A. (1975). The Bradycnemidae, a new family of owls from the Upper Cretaceous of Romania. Palaeontology 18(3): 563-570. doi:10.5281/zenodo.16385950 harrison1975a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Reports the alvarezsaurid hypothesis.

    jones2026c
  3. Meso, J. G.; Pol, D.; Chiappe, L.; Qin, Z.; Díaz-Martínez, I.; Gianechini, F.; Apesteguía, S.; Makovicky, P. J.; Pittman, M. (2024). Body size and evolutionary rate analyses reveal complex evolutionary history of Alvarezsauria. Cladistics 41(2): 135-155. Wiley. doi:10.1111/cla.12600

    Found Heptasteornis an unstable taxon and pruned it from the reduced consensus.

    meso2024a
  4. Naish, D.; Dyke, G. J. (2004). Heptasteornis was no ornithomimid, troodontid, dromaeosaurid or owl: the first alvarezsaurid (Dinosauria: Theropoda) from Europe. Neues Jahrbuch für Geologie und Paläontologie - Monatshefte 2004(7): 385-401.

    Identified Heptasteornis as the first European alvarezsaurid.

    naish2004b
  5. Csiki, Z.; Grigorescu, D. (1998). Small theropods from the Late Cretaceous of the Hateg Basin (western Romania): an unexpected diversity at the top of the food chain. Oryctos 1: 87-104. Musée des Dinosaures d'Espéraza.

    Traces the holotype's provenance to the Sanpetru Formation of the Sibișel Valley, which the describing paper does not state. Regards the tibiotarsi as possibly from a non-maniraptoran tetanuran.

    csiki1998a
  6. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Recovered Heptasteornis as an alvarezsaurid.

    hartman2019a