Open Paleo

Serendipaceratops

Rich & Vickers-Rich, 2003 seh-ren-DIP-uh-SEH-ruh-tops Disputed

From 'serendipitous', referencing the unexpected nature of the find (a ceratopsian found in Australia), and Greek 'keras' meaning 'horn' and 'ops' meaning 'face'; meaning 'serendipitous horned face.'

121.4–113.2 million years ago Aptian, Early Cretaceous
Early Cretaceous stages

Serendipaceratops is a genus of herbivorous ornithischian dinosaur, possibly an ankylosaur, from the early Cretaceous Period of Australia. The type species, S. arthurcclarkei, was named in 2003.

Under dispute

Rich and Vickers-Rich (2003) tentatively referred the ulna to Neoceratopsia. Agnolin and colleagues (2010) find no neoceratopsian synapomorphy, note proportions closer to ankylosaurs, and consider it a nomen dubium diagnosable only to Genasauria. Rich and colleagues (2014) answer with a morphometric study, finding the extreme compression of the ulnar midshaft a synapomorphy of Ceratopsia and the species valid on an emended diagnosis; Ryan and colleagues (2023) still describe the referral as challenged. Its validity and placement are both unsettled, and it is placed at Genasauria incertae sedis.

Diagnosis

  1. Ulnar midshaft extremely compressed mediolaterally (midshaft width ratio 2.06)
  2. Ulna long relative to its mediolateral width but short relative to its craniocaudal depth at the sigmoid fossa rim
  3. Proximal sigmoid region of the ulna narrow relative to the minimum transverse diameter of the midshaft
  4. Coronoid process projecting strongly anteriorly, at a high angle to the shaft
  5. Ulnar shaft narrow, with parallel medial and lateral sides
  6. Robust, mediolaterally inflated lateral tubercle and inflated anterolateral surface on the distal end of the ulna

Species

Serendipaceratops arthurcclarkei Rich & Vickers-Rich, 2003 Disputed

Type species

Named for science fiction writer Arthur C. Clarke, a personal friend of the describing authors and someone who first became interested in science as a child through a fascination with dinosaurs.

Holotype
NMV P186385 , Museums Victoria
Material
A left ulna, missing the region dorsal to the midpoint of the semilunar notch.
Horizon
Wonthaggi Formation, Aptian, Early Cretaceous , 121.4–113.2 million years ago
Locality
The Arch, Victoria, Australia

References

  1. Rich, T.; Vickers-Rich, P. (2003). Protoceratopsian? ulnae from Australia. Records of the Queen Victoria Museum Launceston 113: 1-12. doi:10.5281/zenodo.16207463 rich2003a
  2. Agnolín, F. L.; Ezcurra, M. D.; Pais, D. F.; Salisbury, S. W. (2010). A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities. Journal of Systematic Palaeontology 8(2): 257-300. Informa UK Limited. doi:10.1080/14772011003594870

    Finds no neoceratopsian synapomorphy in the ulna, notes proportions closer to ankylosaurs, and considers the genus a nomen dubium diagnosable only to Genasauria.

    agnolín2010a
  3. Poropat, S. F.; Upchurch, P.; Mannion, P. D.; Hocknull, S. A.; Kear, B. P.; Sloan, T.; Sinapius, G. H. K.; Elliot, D. A. (2014). Revision of the sauropod dinosaur Diamantinasaurus matildae Hocknull et al. 2009 from the mid-Cretaceous of Australia: Implications for Gondwanan titanosauriform dispersal. Gondwana Research 27(3): 995-1033. doi:10.1016/j.gr.2014.03.014

    Reports that a 2014 study renewed support for a ceratopsian identity after it had been met with skepticism.

    poropat2014a
  4. Ryan, M. J.; Micucci, L.; Rizo, H.; Sullivan, C.; Lee, Y. N.; Evans, D. C. (2023). A new Late Cretaceous leptoceratopsid (Dinosauria: Ceratopsia) from the Oldman Formation (Campanian) of Alberta, Canada. Windows into Sauropsid and Synapsid Evolution: Essays in Honor of Prof. Louis L. Jacobs 151-165. Dinosaur Science Center Press.

    Notes that the leptoceratopsid-like affinities reported for the ulnae have been challenged.

    ryan2023a
  5. Rich, T. H.; Kear, B. P.; Sinclair, R.; Chinnery, B.; Carpenter, K.; McHugh, M. L.; Vickers-Rich, P. (2014). Serendipaceratops arthurcclarkei Rich & Vickers-Rich, 2003 is an Australian Early Cretaceous ceratopsian. Alcheringa: An Australasian Journal of Palaeontology 38(4): 456-479. doi:10.1080/03115518.2014.894809

    Finds the ulnar midshaft compression a ceratopsian synapomorphy, rejects the nomen dubium, and gives an emended diagnosis; source of the diagnostic features.

    rich2014a