Fig. 3: Tooth development in a 1 day-old Alligator mississippiensis hatchling (ROM R7964).

a Right dentary of ROM R7964. b Scanning electronic microscopic image of the small embryonic tooth sectioned in (d) (white arrow) showing larger replacement tooth visible in lingual view. c Scanning electronic microscopic image of replacement tooth sectioned in (e) (white arrow) in lingual view. d Thin section of the left dentary of ROM R7964 showing implantation of small, embryonic tooth. The large space lingual to the tooth housed the replacement tooth in (b) that fell out during thin sectioning. e Thin section taken two tooth positions distally from (d) showing size of erupting replacement tooth. f Drawing of (d) showing mode of implantation of embryonic tooth (t1 in red) and position of replacement tooth (t2 in blue). Gray and white indicate jawbone and attachment tissues respectively. g Drawing of erupting tooth in (e). h Enlarged image of embryonic tooth in (d) showing dental tissues. i Enlarged image of replacement tooth in (e) showing dental tissues. Abbreviations: cd, circumpulpal dentine showing dentinal tubules; de, dentine; en, enamel; md, mantle dentine; t1, older embryonic tooth; t2, younger replacement tooth.