Archaeorhynchus
Archaeorhynchus | |
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Fossil specimen, Paleozoological Museum of China | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | Avialae |
Clade: | Ornithothoraces |
Clade: | Euornithes |
Genus: | †Archaeorhynchus Zhou & Zhang, 2006 |
Species: | †A. spathula
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Binomial name | |
†Archaeorhynchus spathula Zhou & Zhang, 2006
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Archaeorhynchus (meaning "ancient snout") is a genus of beaked
Archaeorhychus is one of the earliest avialans known to have had a beak, and represents one of the most basal
Description
Archaeorhynchus was a medium-sized avialan,[1] measuring about 20 centimetres (7.9 in) long, hip height of 15.5 cm (6.1 in), and weight of 275 g (9.7 oz).[3] The three specimens have well-preserved skulls showing important anatomical information, including: slender maxilla and premaxilla, short nasals and discrete mandible elements.[2] The skull bones of the holotype were slightly dislocated due to transportation.[1] All three known fossil specimens have a preserved vertebrae column, although they are not entirely complete. However, when combining the three specimens together, the whole spine could be reconstructed. Based on reconstruction of the vertebrae, it was estimated that the backbone had 9 or 10 neck vertebrae and 9 or 10 tail vertebrae. The back vertebrae were not preserved.[2] Archaeorhynchus had slender and curved vertebral ribs (ribs that do not attach to the breastbone) with robust and strong bases.[2] The pectoral girdle had a robust and U-shaped wishbone, a slightly curved shoulder blade, a short and robust coracoid and a broad and deeply notched breastbone. The hips had an unfused ilium, a slender and curved pubis with a small pubic foot and a strap like ischium which is shorter than the pubis.[2]
The hind limb was shorter than the forelimb. The forelimbs had a
Feathers are preserved in the holotype and one of the two most recent finds, where they are associated with the neck, wing and tail regions.[2]
Relationships
Phylogenetic analysis conducted by Zhou & Zhang indicated that Archaeorhynchus was most closely related to ornithurines. This is based on the fact that the Archaeorhynchus shared advanced features with other ornithurines such as a U-shaped wishbone, a "keel" for flight muscle attachments along the full length of the breastbone, and a compressed and expanded first finger bone of the major manual digit. Nonetheless, Archaeorhynchus also retained primitive features including the lower jaw not being strongly forked at the back, and deep posterior notches in the sternum.[2] The holotype specimen also showed features which suggest powerful flight capability similar to modern birds.[1]
Diet
Scientists have hypothesized that the Archaeorhynchus had an herbivorous diet, due to the large numbers of
Life cycle
A 2021 study on a juvenile specimen shows that, much like Enantiornithes and megapodes, Archaeorhynchus probably demonstrated flight soon after birth.[4]
References
- ^ S2CID 85222311.
- ^ S2CID 86035166.
- ISBN 9780691190594. Retrieved 29 August 2022.)
{{cite book}}
: CS1 maint: multiple names: authors list (link - ^ Foth, C.; Wang, S.; Spindler, F.; Lin, Y.; Yang, R. (2021) "A Juvenile Specimen of Archaeorhynchus Sheds New Light on the Ontogeny of Basal Euornithines". Frontiers in Earth Science. 9: Article 604520 https://doi.org/10.3389/feart.2021.604520
External links
- oficina.cienciaviva.pt: Photo of holotype. Note gastroliths (indicated "GS"). Retrieved 2007-NOV-2.