Ornithothoraces

Reconstruction of Vorona berivotrensis, by Kawekaweau.

Belongs within: Avialae.
Contains: Ornithurae.

The Ornithothoraces is the clade uniting the modern birds with the Enantiornithes, a clade of stem birds that was significant in the Cretaceous but did not survive the end of the Mesozoic. The name 'Ornithothoraces' refers to the develop of an enlarged, keeled sternum allowing a greater surface for the attachment of the flight muscles. The Enantiornithes were morphologically and ecologically diverse, including both toothed and toothless forms. They exhibited a distinct mode of fusion of the foot bones from the lineage leading to modern birds, with the metatarsals fusing from the ankle towards the toes instead of from the midpoint towards both ends as in the latter lineage (Padian 2004). Other early Ornithothoraces include Vorona berivotrensis from the Late Cretaceous of Madagascar.

Synapomorphies (from Clarke 2004): Eight or nine ankylosed sacral vertebrae; ossified sternal plates fused with projected keel; scapula and coracoid unfused; angle between coracoid and scapula at glenoid 90° or less; scapula tapering distally; humerus with ventral tubercle and capital incisure present, transverse groove present (developed as discrete, depressed scar on proximal surface of bicipital crest or as slight transverse groove), bicipital crest developed as anterior projection relative to shaft surface in ventral view; distal end of dorsal condyle of ulna with dorsal trochlear surface developed as semilunate ridge; semilunate carpal and metacarpals completely fused proximally; pisiform process present; tibia/tarsal formed condyles equal in anterior projection.

<==Ornithothoraces C04
    |  i. s.: Kuszholia Nessov 1992 P04
    |           `--K. mengi Nessov 1992 P04
    |--Vorona Forster, Chiappe et al. 1996 ZZ05, P04
    |    `--V. berivotrensis Forster, Chiappe et al. 1996 P04
    `--+--Ornithuromorpha P04
       |    |--Archaeorhynchus GC13
       |    `--+--Patagopteryx Alvarenga & Bonaparte 1992 C04, P04
       |       |    `--P. deferrariisi Alvarenga & Bonaparte 1992 P04
       |       `--+--Schizooura GC13
       |          `--+--Jianchangornis GC13
       |             `--Ornithurae C04
       `--Enantiornithes C04
            |  i. s.: Nanantius Molnar 1986 P04
            |           `--N. eos Molnar 1986 P04
            |         Aberratiodontus Gong, Hou & Wang 2004 [Aberratiodontuidae, Aberratiodontuiformes] GHW04
            |           `--*A. wui Gong, Hou & Wang 2004 GHW04
            |         Zhyraornis Nessov 1984 P04
            |           |--Z. kashkarovi Nessov 1984 P04
            |           `--Z. logunovi Nessov 1992 P04
            |         ‘Ichthyornis’ minusculus Nessov 1990 (n. d.) C04, P04
            |         Alexornis Brodkorb 1976 P04
            |           `--A. antecedens Brodkorb 1976 P04
            |         Avisaurus Brett-Surman & Paul 1985 P04
            |           |--A. archibaldi Brett-Surman & Paul 1985 P04
            |           `--A. gloriae Varricchio & Chiappe 1995 P04
            |         Boluochia Zhou 1995 P04
            |           `--B. zhengi Zhou 1995 P04
            |         Eocathayornis Zhou 2002 P04
            |           `--E. walkeri Zhou 2002 P04
            |         Eoenantiornis Hou, Martin et al. 1999 P04
            |           `--E. buhleri Hou, Martin et al. 1999 P04
            |         Gurilynia Kurochkin 1999 P04
            |           `--G. nessovi Kurochkin 1999 P04
            |         Halimornis Chiappe, Lamb & Ericson 2002 P04
            |           `--H. thompsoni Chiappe, Lamb & Ericson 2002 P04
            |         Kizylkumavis Nesson 1984 P04
            |           `--K. cretacea Nessov 1984 P04
            |         Lectavis Chiappe 1993 P04
            |           `--L. bretincola Chiappe 1993 P04
            |         Lenesornis Kurochkin 1996 P04
            |           `--L. maltshevskyi (Nessov 1986) [=Ichthyornis maltshevskyi] P04
            |         Otogornis Hou 1994 P04
            |           `--O. genghisi Hou 1994 P04
            |         Sazavis Nessov & Yarkov 1989 P04
            |           `--S. prisca Nessov & Yarkov 1989 P04
            |         Soroavisaurus Chiappe 1993 P04
            |           `--S. australis Chiappe 1993 P04
            |         Yungavolucris Chiappe 1993 P04
            |           `--Y. brevipedalis Chiappe 1993 P04
            |         Enantiornis Walker 1981 P04
            |           |--E. leali Walker 1981 P04
            |           |--E. martini Nessov & Panteleyev 1993 P04
            |           `--E. walkeri Nessov & Panteleyev 1993 P04
            |         Liaoxiornis Hou & Chen 1999 [=Lingyuanornis] D07
            |           `--L. delicatus SD11
            |         Longirostravis ZZ05
            |         Iberomesornis Sanz & Bonaparte 1992 P04
            |           `--I. romerali Sanz & Bonaparte 1992 P04
            |         Noguerornis Lacasa-Ruiz 1989 P04
            |           `--N. gonzalezi Lacasa-Ruiz 1989 P04
            |--Protopteryx Zhang & Zhou 2000 GC13, P04
            |    `--P. fengningensis Zhang & Zhou 2000 P04
            `--+--Pengornis GC13
               `--+--Longipteryx Zhang, Zhou et al. 2001 GC13, ZZ01 [Longipterygidae, Longipterygiformes]
                  |    `--*L. chaoyangensis Zhang, Zhou et al. 2001 ZZ01
                  `--Euenantiornithes P04
                       |  i. s.: Sinornis Sereno & Rao 1992 P04
                       |           `--S. santensis Sereno & Rao 1992 P04
                       |         Eoalulavis Sanz, Chiappe et al. 1996 P04
                       |           `--E. hoyasi Sanz, Chiappe et al. 1996 P04
                       |--+--Neuquenornis Chiappe & Calvo 1994 ZZ05, P04
                       |  |    `--N. volans Chiappe & Calvo 1994 P04
                       |  `--+--Gobipteryx Elżanowski 1974 ZZ05, P04
                       |     |    `--G. minuta Elżanowski 1974 [incl. Nanantius valifanovi Kurochkin 1996] P04
                       |     `--Concornis Sanz & Buscalioni 1992 ZZ05, P04
                       |          `--C. lacustris Sanz & Buscalioni 1992 P04
                       `--Cathayornithiformes LH07
                            |--Cathayornis Zhou, Jin & Zhang 1992 ZZ05, P04
                            |    `--C. yandica Zhou, Jin & Zhang 1992 P04
                            `--Alethoalaornis Li, Hu et al. 2007 [Alethoalaornithidae] LH07
                                 `--*A. agitornis Li, Hu et al. 2007 LH07

*Type species of generic name indicated

REFERENCES

[C04] Clarke, J. A. 2004. Morphology, phylogenetic taxonomy, and systematics of Ichthyornis and Apatornis (Avialae: Ornithurae). Bulletin of the American Museum of Natural History 286: 1–179.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[GC13] Godefroit, P., A. Cau, Hu D.-Y., F. Escuillié, Wu W. & G. Dyke. 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature 498: 359–362.

[GHW04] Gong E., Hou L. & Wang L. 2004. Enantiornithine bird with diapsidian skull and its dental development in the Early Cretaceous in Liaoning, China. Acta Geologica Sinica (English Edition) 78 (1): 1–7.

[LH07] Li L., Hu D.-Y., Duan Y., Gong E.-P. & Hou L.-H. 2007. Alethoalaornithidae fam. nov., a new family of enantiornithine bird from the Lower Cretaceous of western Liaoning. Acta Palaeontologica Sinica 46 (3): 365–372.

[P04] Padian, K. 2004. Basal Avialae. In: Weishampel, D. B., P. Dodson & H. Osmólska (eds) The Dinosauria 2^nd ed. pp. 210–231. University of California Press: Berkeley.

[SD11] Sun, G., D. L. Dilcher, H. Wang & Z. Chen. 2011. A eudicot from the Early Cretaceous of China. Nature 471: 625–628.

[ZZ01] Zhang F., Zhou Z., Hou L. & Gu G. 2001. Early diversification of birds: evidence from a new opposite bird. Chinese Science Bulletin 46 (11): 945–949.

[ZZ05] Zhou, Z., & F. Zhang. 2005. Discovery of an ornithurine bird and its implications for Early Cretaceous avian radiation. Proceedings of the National Academy of Sciences of the USA 102: 18998–19002.

Last updated: 1 August 2017.