Bellairsia

Bellairsia is an extinct genus of stem-squamate known from a single species, Bellairsia gracilis, from the Middle Jurassic (Bathonian) of England and Scotland. It is amongst the oldest squamates known. It was originally described in 1998 by Susan E. Evans from disarticulated individual bones, including the holotype dentary, collected from the Forest Marble Formation in Kirtlington Quarry, Oxfordshire, England. It was named in honor of British herpetologist and vertebrate anatomist Angus Bellairs. In 2022, a partial 70% complete skeleton was described from the equivalently aged Kilmaluag Formation of the Isle of Skye, Scotland. The partial skeleton had an estimated snout-vent length of around 6–7 centimetres (2.4–2.8 in). While originally considered a member of Scincomorpha, the 2022 study recovered it to be a stem-group squamate, with the phylogeny recovering it as part of a weakly supported clade also containing Huehuecuetzpalli and Oculudentavis.^[1][2]

Bellairsia Temporal range: Middle Jurassic Bathonian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Skull diagram
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Genus:	†Bellairsia Evans 1998
Species:	†B. gracilis
Binomial name
†Bellairsia gracilis Evans, 1998

Classification

Phylogeny after Talanda et al. (2022):

	Archosauromorpha Lepidosauromorpha †Paliguana †Megachirella †Fraxinisaura †Marmoretta crown-Lepidosauria †Sophineta Rhynchocephalia †Bellairsia †Oculudentavis †Huehuecuetzpalli stem-Squamata crown-Squamata

References

1. S. E. Evans. 1998. Crown group lizards (Reptilia, Squamata) from the Middle Jurassic of the British Isles. Palaeontographica Abteilung A 250:123-154
2. Tałanda, Mateusz; Fernandez, Vincent; Panciroli, Elsa; Evans, Susan E.; Benson, Roger J. (2022-10-26). "Synchrotron tomography of a stem lizard elucidates early squamate anatomy". Nature. 611 (7934): 99–104. doi:10.1038/s41586-022-05332-6. ISSN 0028-0836. PMID 36289329. S2CID 253160713.