Embryos of therizinosauroid theropods from the Upper Cretaceous of China: Diagnosis and analysis of ossification patterns

Martin Kundrát, Arthur R I Cruickshank, Terry W. Manning, John Nudds

    Research output: Contribution to journalArticlepeer-review


    Exceptionally complete, in ovo dinosaur embryos from the Upper Cretaceous of China are analysed. Ossification patterns of these embryos suggest that they died during the final third of their development. The therizinosauroid identity of the embryos follows from: (1) an edentulous premaxilla with a sharp downturned edge; (2) dentary with a lateral shelf; (3) teeth with fan-shaped crowns, with a few marginal cusps; (4) humerus with a massive deltopectoral crest extending proximally, with a pointed proximomedial tuberosity; (5) ilium with an expanded and hooked preacetabular process; (6) strongly curved hypertrophied manual unguals tapering to sharp points. These embryos are closest to two Chinese therizinosauroids, Neimongosaurus yangi Zhang et al. 2001 and Erliansaurus bellamanus Xu et al. 2002. An elongated narial opening, reduced basipterygoid process, low cervical neural spines, a transversely narrow pubic apron, and a pubic foot expanded anteriorly are found in these embryos and are synapomorphies uniting the Therizinosauroidea and the Oviraptorosauria. Fusion of cervical and caudal neural arches and centra, complete ossification of thoracic ribs and ilium, possible co-ossification of tibia and fibula, fused pubes, complete meta- and acropodial elements, together with small portions of unossified epiphyses of long bones suggest an advanced precociality of these embryos. © 2007 The Authors.
    Original languageEnglish
    Pages (from-to)231-251
    Number of pages20
    JournalActa Zoologica
    Issue number3
    Publication statusPublished - Jul 2008


    • Development
    • Embryo
    • Ontogeny
    • Ossification
    • Phylogeny
    • Precociality
    • Systematics
    • Therizinosauroidea
    • Theropoda


    Dive into the research topics of 'Embryos of therizinosauroid theropods from the Upper Cretaceous of China: Diagnosis and analysis of ossification patterns'. Together they form a unique fingerprint.

    Cite this