Caption
Micro-computed tomography and histology of the non-synovial otic joint in hatchling (a-d), juvenile (e-h) and adult American alligator (i-l) demonstrate the unique morphology of the articulation between the condylar otic process of the quadrate capped with primary articular cartilage, and the fibre-filled cotyle of the squamosal. Three-dimensional CT reconstructions are shown in a hatchling (a), juvenile (e) and an adult alligator (i). Red lines indicate planes of CT and histological sections in (b,f and j), and (c,g and k), respectively, followed by higher magnifications in (d, h, and l). Specimen numbers: OUVC10606 in (a,b), MUVC-AL050 in (c,d), MUVC-AL623 in (e,f), MUVC-AL075 in (g,h), MUVC-AL721 in (i,j), MUVC-AL039 in (k,l). ac, articular cartilage; b, bone; cc, calcified cartilage; dct; dense connective tissue; fc, fibrocartilage; hc, hyaline cartilage; lct, loose connective tissue; pz, proliferative zone; Qu, quadrate; scb, subchondral bone; Sq, squamosal.