Editing Tuatara (section)

==== Eyes ====
The eyes can [[Accommodation (eye)|focus]] independently, and are specialised with three types of photoreceptive cells, all with fine structural characteristics of retinal [[cone cell]]s<ref>{{cite journal |vauthors=Meyer-Rochow VB, Wohlfahrt S, Ahnelt PK |year=2005 |title=Photoreceptor cell types in the retina of the tuatara (Sphenodon punctatus) have cone characteristics |url=https://www.sciencedirect.com/science/article/abs/pii/S0968432805000521 |journal=Micron |volume=36 |issue=5 |pages=423–428 |doi=10.1016/j.micron.2005.03.009 |pmid=15896966}}</ref> used for both day and night vision, and a ''[[tapetum lucidum]]'' which reflects onto the retina to enhance vision in the dark. There is also a third eyelid on each eye, the [[nictitating membrane]]. Five visual [[opsin]] genes are present, suggesting good [[colour vision]], possibly even at low light levels.<ref name="Gemmell2020">{{cite journal |vauthors=Gemmell NJ, Rutherford K, Prost S, Tollis M, Winter D, Macey JR, Adelson DL, Suh A, Bertozzi T, Grau JH, Organ C, Gardner PP, Muffato M, Patricio M, Billis K, Martin FJ, Flicek P, Petersen B, Kang L, Michalak P, Buckley TR, Wilson M, Cheng Y, Miller H, Schott RK, Jordan MD, Newcomb RD, Arroyo JI, Valenzuela N, Hore TA, Renart J, Peona V, Peart CR, Warmuth VM, Zeng L, Kortschak RD, Raison JM, Zapata VV, Wu Z, Santesmasses D, Mariotti M, Guigó R, Rupp SM, Twort VG, Dussex N, Taylor H, Abe H, Bond DM, Paterson JM, Mulcahy DG, Gonzalez VL, Barbieri CG, DeMeo DP, Pabinger S, Van Stijn T, Clarke S, Ryder O, Edwards SV, Salzberg SL, Anderson L, Nelson N, Stone C |date=August 2020 |title=The tuatara genome reveals ancient features of amniote evolution |journal=Nature |volume=584 |issue=7821 |pages=403–409 |doi=10.1038/s41586-020-2561-9 |pmc=7116210 |pmid=32760000 |doi-access=free}}</ref>