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. 2018 Nov 7;285(1890):20181792. doi: 10.1098/rspb.2018.1792

Figure 1.

Figure 1.

Tooth attachment in stem and crown mammals (Synapsida). (a) Cladogram of the evolutionary relationships of the major taxa within Synapsida (modified from [5,20,25]). (b–l) thin sections showing tooth attachment tissues in major synapsid groups. (b) The sphenacodontid Dimetrodon (ROM 6039). (c) An indeterminate dinocephalian (BP/1/4851). (d) The anomodont Diictodon (ROM 52624). (e) A second individual of Diictodon (ROM 52624). (f) An indeterminate gorgonopsian (NMT RB404). (g) An indeterminate therocephalian (BP/1/7257). (h) The same therocephalian, but an adjacent tooth position. (i) The derived therocephalian Bauria (BP/1/2523). (j) The cynodont Cynognathus (BP/1/6097). (k) The cynodont Diademodon (BP/1/4652). (l) The extinct ungulate mammal Hyopsodus (USNM 595273). (m) A stained section of the periodontium in an extant badger (Taxidea). (n) Illustrated the arrangement of the attachment tissues of the gomphosis in Synapsida. ab, alveolar bone (grey); ac, acellular cementum (blue); cc, cellular cementum (blue); de, dentine; jb, jawbone; pdl, periodontal ligament (red). Asterisks indicate spaces formerly occupied by periodontal ligament in life.