Navaornis

Navaornis is an extinct genus of enantiornithean birds from the Late Cretaceous Adamantina Formation of Brazil. The genus contains a single species, N. hestiae, known from a well preserved skull and skeleton.^[1]

Navaornis Temporal range: Late Cretaceous (late Santonian–early Campanian), 85–75 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil material of Navaornis (white and light grey in "b") and an unnamed specimen (dark grey)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Avialae
Clade:	†Enantiornithes
Genus:	†Navaornis Chiappe et al., 2024
Species:	†N. hestiae
Binomial name
†Navaornis hestiae Chiappe et al., 2024

Discovery and naming

Preserved holotype skull and diagram

Three-dimensional cranial reconstruction of Navaornis

The Navaornis fossil material was discovered in 2016 in sediments of the Adamantina Formation ('William's Quarry' bonebed, Bauru Group) in São Paulo State, southeastern Brazil. The holotype specimen comprises a complete skull with an associated postcranial skeleton. A single basicranium described in 2022 was also referred to Navaornis based on its similarities with the holotype.^[1][2]

In 2024, Chiappe et al. described Navaornis hestiae as a new genus and species of enantiornithean birds based on these fossil remains. The generic name, Navaornis, combines "Nava"—honoring William Nava, the discoverer of the holotype and type locality—with the Greek word "ornis", meaning "bird". The specific name, hestiae, references the Greek goddess Hestia, who is considered to be both the oldest and youngest Olympian—similar to the archaic phylogenetic position of Navaornis combined with its modern skull morphology.^[1]

Classification

In their phylogenetic analyses, Chiappe et al. (2024) recovered Navaornis as a derived member of the extinct Cretaceous bird clade Enantiornithes, clustering with Yuornis and Gobipteryx, two other edentulous birds with beaks. However, they noted that due to the low support for specific enantiornithean relationships, this grouping may not represent a legitimate toothless clade. Their results are displayed in the cladogram below:^[1]

Enantiornithes

Protopteryx Orienantius Eopengornis Parapengornis Shenqiornis Junornis Gretcheniao Sulcavis Zhouornis Longusunguis Bohaiornis Qiliania Parabohaiornis Vescornis Neuquenornis Pengornis Eoenantiornis CUGB P1202 (indeterminate unnamed enantiornithean)[3] Concornis Elsornis Longipteryx Shanweiniao Longirostravis Rapaxavis Fortunguavis Iberomesornis Eoalulavis Cathayornis Eocathayornis Gobipteryx Yuornis Navaornis

References

1. Chiappe, Luis M.; Navalón, Guillermo; Martinelli, Agustín G.; Carvalho, Ismar de Souza; Miloni Santucci, Rodrigo; Wu, Yun-Hsin; Field, Daniel J. (2024-10-30). "Cretaceous bird from Brazil informs the evolution of the avian skull and brain". Nature. 635 (8038): 376–381. doi:10.1038/s41586-024-08114-4. ISSN 1476-4687. PMC 11560842.
2. Chiappe, Luis M.; Navalón, Guillermo; Martinelli, Agustín G.; Nava, William; Field, Daniel J. (2022-09-28). "Fossil basicranium clarifies the origin of the avian central nervous system and inner ear". Proceedings of the Royal Society B: Biological Sciences. 289 (1983). doi:10.1098/rspb.2022.1398. ISSN 0962-8452. PMC 9515635. PMID 36168759.
3. Peteya, Jennifer A.; Clarke, Julia A.; Li, Quanguo; Gao, Ke-Qin; Shawkey, Matthew D. (2017). Gabbott, Sarah (ed.). "The plumage and colouration of an enantiornithine bird from the Early Cretaceous of China". Palaeontology. 60 (1): 55–71. Bibcode:2017Palgy..60...55P. doi:10.1111/pala.12270. ISSN 0031-0239. S2CID 89530170.