Open Paleo

Anchiornis

Xu et al., 2009 an-kee-OR-niss

From Greek 'anchi' meaning 'near' and 'ornis' meaning 'bird', meaning 'near bird', reflecting its close morphological similarity to modern birds.

165.3–149.2 million years ago Callovian–Kimmeridgian, Middle Jurassic–Late Jurassic
Middle Jurassic and Late Jurassic stages

Anchiornis is a genus of small, four-winged paravian dinosaurs, with only one known species, the type species Anchiornis huxleyi, named for its similarity to modern birds. Anchiornis fossils have been found only in the Tiaojishan Formation of Liaoning, China, in rocks dated to the Late Jurassic, about 160 million years ago. It is known from hundreds of specimens, and given the exquisite preservation of some of these fossils, it became the first Mesozoic dinosaur species for which almost the entire life appearance could be determined, and an important source of information on the early evolution of birds.

Diagnosis

  1. Ventral surface of the coracoid sculptured by numerous small pits.
  2. Extremely short ischium, less than one-fourth of femoral length.
  3. Tibiotarsus approximately 150% of femur length, substantially longer proportionally than any other known non-avian theropod.
  4. Manual phalanx II-1 much thicker than all other manual phalanges and nearly as thick as the ulna.
  5. Estimated body mass of approximately 110 grams, making it the smallest known non-avian theropod at time of description.

Species

Anchiornis huxleyi Xu et al., 2009

Type species

Named for Thomas Henry Huxley, an early proponent of biological evolution and one of the first to propose a close evolutionary relationship between birds and dinosaurs.

Holotype
IVPP V14378 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Articulated skeleton missing only the skull, anterior and middle cervical vertebrae, and posterior caudal vertebrae, with faint feather impressions on slab and counter slab.
Horizon
Tiaojishan Formation, Callovian–Kimmeridgian, Middle Jurassic–Late Jurassic , 165.3–149.2 million years ago
Locality
Yaolugou, Liaoning, China Xu and colleagues (2009) place the holotype at Yaolugou in lacustrine deposits they date only as uncertainly Jurassic to Cretaceous, naming no unit. Godefroit and colleagues (2013) give the same locality as "Yaolugou, Jianchang, western Liaoning, China; Middle-Late Jurassic Tiaojishan Formation", noting that "The Tiaojishan formation is widely exposed in this area", and Hu and colleagues (2009) give the Tiaojishan for a referred specimen from nearby Daxishan.

Notable specimens

  • STM 0-214

    Shandong Tianyu Museum of Nature exceptional preservation

    Very well preserved specimen showing visible color patterns; photographed for a 2011 National Geographic article and used in a study of Anchiornis covert feathers and wing anatomy.

    Longrich et al. (2012)

  • BMNHC PH828

    Beijing Museum of Natural History exceptional preservation

    Nearly complete skeleton preserving extensive feathers and a head crest, used in a 2010 melanosome survey to map nearly the entire life coloration, making Anchiornis the first Mesozoic dinosaur for which almost the full life color was reconstructed.

    Li et al. (2010)

  • YFGP-T5199

    Yizhou Fossil and Geology Park exceptional preservation

    Nearly complete skeleton used for a scanning electron microscope study of feather microstructure and melanosomes; the 2015 survey found only gray-black melanosomes, contrasting the earlier rufous-crest reconstruction of BMNHC PH828.

    Lindgren et al. (2015)

References

  1. Xu, X.; Zhao, Q.; Norell, M.; Sullivan, C.; Hone, D.; Erickson, G.; Wang, X.; Han, F.; Guo, Y. (2009). A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin. Science Bulletin 54(3): 430-435. Elsevier BV. doi:10.1007/s11434-009-0009-6 xu2009c
  2. Li, Q.; Gao, K. Q.; Vinther, J.; Shawkey, M. D.; Clarke, J. A.; D'Alba, L.; Meng, Q.; Briggs, D. E. G.; Prum, R. O. (2010). Plumage color patterns of an extinct dinosaur. Science 327(5971): 1369-1372. doi:10.1126/science.1186290 li2010b
  3. Longrich, N. R.; Vinther, J.; Meng, Q.; Li, Q.; Russell, A. P. (2012). Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi. Current Biology 22(23): 2262-2267. doi:10.1016/j.cub.2012.09.052 longrich2012a
  4. Lindgren, J.; Sjövall, P.; Carney, R. M.; Cincotta, A.; Uvdal, P.; Hutcheson, S. W.; Gustafsson, O.; Lefèvre, U.; Escuillié, F.; Heimdal, J.; Engdahl, A.; Gren, J. A.; Kear, B. P.; Wakamatsu, K.; Yans, J.; Godefroit, P. (2015). Molecular composition and ultrastructure of Jurassic paravian feathers. Scientific Reports 5: 13520. doi:10.1038/srep13520 lindgren2015a
  5. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

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

    jones2026c
  6. Hu, D.; Hou, L.; Zhang, L.; Xu, X. (2009). A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature 461(7264): 640-643. Springer Science and Business Media LLC. doi:10.1038/nature08322 hu2009a
  7. Godefroit, P.; Demuynck, H.; Dyke, G.; Hu, D.; Escuillié, F.; Claeys, P. (2013). Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature Communications 4(1). Springer Science and Business Media LLC. doi:10.1038/ncomms2389

    Places the Yaolugou locality in the Tiaojishan Formation.

    godefroit2013a