Fig. 3: Comparative analysis of patterns of dental ontogeny.
From: Dental evidence for extended growth in early Homo from Dmanisi
a, Dental ontogenetic schedule by tooth type (Dmanisi, red; humans, green; chimpanzees (captive individuals), blue; dark/light hues indicate crown/root formation periods; small squares indicate estimated eruption time). Error bars (±1 s.d.) drawn at crown initiation and completion, tooth emergence and root completion (data represent n = 25 independent human population-level studies and n = 10 independent studies on chimpanzees; see source data for details). The symbols below the abscissa indicate estimated mean ages at M1 emergence in other great apes (captive gorillas, orange triangle; captive orangutans, orange square) and in fossil hominins (A. afarensis, circle; A. africanus, + sign; P. robustus, Y sign; early Homo, × sign). b, PCA of dental maturation patterns (DMS-PCA) (Dmanisi, red trajectory; humans, green dots and trajectory; captive known-age chimpanzees, blue dots and trajectory; numbers on trajectories indicate age in years; wild-living chimpanzees, blue circles; wild-living bonobos, blue diamonds; wild/captive gorillas, open/filled orange triangles; wild/captive orangutans, open/filled orange squares; A. afarensis, black circles (Dikika, AL333-105); A. africanus, + signs (Sts24, Taung); P. robustus, Y signs (DNH107, SK63); early Homo, × signs (KNM-ER1590, ZKD B-I4, KNM-WT 15000)). Each data point summarizes the maturation states of teeth I1–M3 of a given dentition. Insets show maturation patterns at selected locations in PC space. At comparable ages (6 years), the posterior dentition in humans is delayed compared to chimpanzees. At similar stages of advancement along the ontogenetic trajectory (chimpanzees: 6 years; humans: 9 years), the anterior dentition of chimpanzees appears relatively delayed compared to that of humans48. For data sources, see Supplementary Data 4.
