Open Paleo

Jeholornis

Zhou & Zhang, 2002 juh-HOHL-OR-nis

From the Jehol Group (the Lower Cretaceous geological unit of western Liaoning, named after the historical region of Jehol/Rehe) plus Greek 'ornis' (bird); meaning 'Jehol bird'.

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Jeholornis is a genus of avialan dinosaurs that lived between approximately 122 and 120 million years ago during the early Cretaceous Period in China. Fossil Jeholornis were first discovered in the Jiufotang Formation in Hebei Province, China (in what was previously Rehe Province, also known as Jehol — hence the name) and additional specimens have been found in the older Yixian Formation.

Under dispute

The synonymy with Shenzhouraptor Ji and colleagues, 2002 is actively contested. Most workers (Ji and colleagues 2003; Zhou and Zhang 2006, 2007; Li and colleagues 2010; Lefèvre and colleagues 2014) accept the synonymy: Shenzhouraptor sinensis and Jeholornis prima are treated as the same species, with Jeholornis having ICZN priority because Nature carries a specific publication date (25 July 2002) while the Geological Bulletin of China is a monthly journal without a specific issue date. Wang and colleagues (2020) dissented, identifying multiple distinguishing characters and recovering Shenzhouraptor sinensis phylogenetically outside Jeholornis sensu stricto. The intake follows the majority position (Jeholornis senior, Shenzhouraptor junior synonym) while flagging the dispute.

Diagnosis

  1. Lachrymal T-shaped with two vertical, elongated pneumatic fossae.
  2. Mandibles robust with well-ossified (fused) symphysis.
  3. First phalanx of third manual digit approximately twice the length of the second phalanx, forming a bow-shaped structure together.
  4. Tail with at least twenty elongated caudal vertebrae behind the transition point, bearing distinctively elongated prezygapophyses and chevrons.
  5. Lateral trabecula of the sternum bearing a rounded fenestra at its distal end.
  6. Forelimb-to-hindlimb ratio (humerus + ulna + carpometacarpus over femur + tibiotarsus + tarsometatarsus) approximately 1.2.

Species (3)

Jeholornis prima Zhou & Zhang, 2002

Type species

From Latin 'prima' (first), in reference to the primitive appearance of the tail.

Holotype
IVPP V13274 , Institute of Vertebrate Paleontology and Paleoanthropology
Material
Nearly completely articulated skeleton preserved on five slabs, including a partially articulated skull and nearly complete postcranial bones; >50 ovules (Carpolithus) preserved in the stomach region as direct evidence of seed-eating.
Horizon
Jiufotang Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Dapingfang, Chaoyang City, Liaoning, China

Jeholornis palmapenis O'Connor et al., 2012

From Latin 'palma' (palm) and 'penis' (tail), in reference to the palm-tree-like appearance of the preserved caudal rectrices.

Holotype
SDM 20090109.1 , Museum in the Park
Material
Nearly fully articulated but incomplete skeleton (slab SDM 20090109.1 + counter slab SDM 20090109.2), missing pectoral girdle and forelimbs, with complete caudal integument.
Horizon
Jiufotang Formation, Aptian, Early Cretaceous , 121.4–113.2 million years ago
Locality
Jianchang, Liaoning, China

Jeholornis curvipes Lefèvre et al., 2014

From Latin 'curvus' (curved) and 'pes' (foot), in reference to the lateral deviation of the distal metatarsals in the holotype YFGP-yb2.

Holotype
YFGP-yb2 , Yizhou Fossil and Geology Park
Material
Almost completely articulated skeleton (housed at the Yizhou Fossil and Geology Park, specimen YFGP-yb2) including a partial caudal series; rostral skull, right forelimb and right hindlimb distal autopodia were reconstructed during preparation.
Horizon
Dawangzhangzi Member, Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Liaoning, China Lefèvre and colleagues (2014) give the horizon as the "Dakangpu Member (equivalent to the Dawangzhangzi Beds) of the Yixian Formation, lower Aptian", while dating the formation at "124.6 ± 0.3 Mya using U-Pb SHRIMP dating", which is Barremian on the ICS chart v2024/12. They give the type locality as "Yizhou Fossil and Geology Park, Liaoning Province", the name of the institution that holds the holotype.

Synonyms of the genus

Name Type Reason
Shenzhouraptor junior subjective Ji and colleagues (2002) erected Shenzhouraptor sinensis for LPM 0193 in the same Jiufotang Formation, only days before (and in a less precisely dated journal than) Zhou and Zhang's Jeholornis prima Nature paper. Ji and colleagues 2003, Zhou and Zhang (2006, 2007), Li and colleagues (2010), and Lefèvre and colleagues (2014) treat Shenzhouraptor sinensis as a junior subjective synonym of Jeholornis prima with Jeholornis given priority on ICZN grounds (specific Nature publication date over monthly Geological Bulletin of China). Wang and colleagues (2020) dissent (see dispute field).

Notable specimens

  • STM2-51

    Shandong Tianyu Museum of Nature reproductive

    Referred specimen that preserves round structures in the body cavity interpreted as ovaries, offering rare evidence of the reproductive anatomy of this early avialan.

    Zheng et al. (2013)

References

  1. Zhou, Z.; Zhang, F. (2002). A long-tailed, seed-eating bird from the Early Cretaceous of China. Nature 418(6896): 405-409. doi:10.1038/nature00930

    Original description of Jeholornis prima on holotype IVPP V13274 from the Jiufotang Formation; the type specimen preserved >50 stomach-region seeds documenting seed-eating.

    zhou2002a
  2. Ji, Q.; Ji, S. A.; You, H. L.; Zhang, J. P.; Yuan, C. X.; Ji, X. X.; Li, J. L.; Li, Y. X. (2002). A new avialian bird - Shenzhouraptor sinensis gen. et sp. nov. - from the Mesozoic of northeastern China. Geological Bulletin of China 21(7): 363-369.

    Describes Shenzhouraptor sinensis on LPM 0193 from the Jiufotang Formation; most subsequent workers treat Shenzhouraptor as a junior subjective synonym of Jeholornis.

    ji2002a
  3. Zhou, Z.; Zhang, F. (2003). Jeholornis compared to Archaeopteryx, with a new understanding of the earliest avian evolution. Naturwissenschaften 90(5): 220-225. doi:10.1007/s00114-003-0416-5

    Comparative anatomy of two new juvenile Jeholornis prima specimens (IVPP V13553, V13550), documenting progressive tooth reduction and tail morphology relative to Archaeopteryx.

    zhou2003a
  4. O'Connor, J. K.; Sun, C.; Xu, X.; Wang, X. L.; Zhou, Z. (2012). A new species of Jeholornis with complete caudal integument. Historical Biology 24(1): 29-41. doi:10.1080/08912963.2011.552720

    Erects Jeholornis palmapenis on SDM 20090109.1, diagnosed by toothed maxilla, strongly convex ilium dorsal margin, and a fan of 11 palm-frond-shaped caudal rectrices.

    o'connor2012a
  5. Lefèvre, U.; Hu, D.; Escuillié, F.; Dyke, G.; Godefroit, P. (2014). A new long-tailed basal bird from the Lower Cretaceous of north-eastern China. Biological Journal of the Linnean Society 113(3): 790-804. doi:10.1111/bij.12343

    Erects Jeholornis curvipes on YFGP-yb2 from the Yixian Dakangpu Member (~124.6 Ma); synonymizes Shenzhouraptor sinensis with J. prima.

    lefèvre2014a
  6. Wang, X.; Cau, A.; Luo, X.; Kundrát, M.; Wu, W.; Ju, S.; Guo, Z.; Liu, Y.; Ji, Q. (2020). A new jeholornithiform exhibits the earliest appearance of the fused sternum and pelvis in the evolution of avialan dinosaurs. Journal of Asian Earth Sciences 199: 104401. doi:10.1016/j.jseaes.2020.104401

    Describes Kompsornis longicaudus and re-evaluates Shenzhouraptor sinensis as a distinct valid species outside Jeholornis sensu stricto; the dissenting view in the synonymy debate.

    wang2020b
  7. Zheng, X.; O'Connor, J.; Huchzermeyer, F.; Wang, X.; Wang, Y.; Wang, M.; Zhou, Z. (2013). Preservation of ovarian follicles reveals early evolution of avian reproductive behaviour. Nature 495(7442): 507-511. doi:10.1038/nature11985 zheng2013a
  8. Zhou, Z.; Zhang, F. (2006). Mesozoic birds of China — a synoptic review. Vertebrata PalAsiatica 44(1): 74-98.

    Reviewed Mesozoic birds of China, including Jeholornis.

    zhou2006a
  9. Li, D. S.; Sullivan, C.; Zhou, Z. H.; Zhang, F. C. (2010). Basal birds from China: a brief review. Chinese Birds 1(2): 83-96. doi:10.5122/cbirds.2010.0002 li2010c
  10. Ji, Q.; Ji, S. A.; You, H. L.; Zhang, J. P.; Zhang, H. B.; Zhang, N. J.; Yuan, C. X.; Ji, X. X. (2003). An Early Cretaceous avialian bird, Shenzhouraptor sinensis from western Liaoning, China. Acta Geologica Sinica (English Edition) 77(1): 21-27. doi:10.1111/j.1755-6724.2003.tb00106.x ji2003b
  11. Zhou, Z.; Zhang, F. (2007). Mesozoic birds of China — a synoptic review. Frontiers of Biology in China 2(1): 1-14. doi:10.1007/s11515-007-0001-y zhou2007b