Figure 6 in Ontogeny and evolutionary significance of a new acrotretide brachiopod genus from Cambrian Series 2 of South China

Figure 6. Ontogenetic development of pedicle foramen of Palaeotreta shannanensis gen. et sp. nov. from the Shuijingtuo Formation of southern Shaanxi. A, B, juvenile with unrestricted pedicle notch, note raised propareas (arrows), ELI-XYB S4-3 AV-09; C, D, juvenile with unrestricted pedicle notch, ELI-XYB S4-3 AV-17; E–G, semicircular pedicle foramen soon to be enclosed, ELI-XYB S4-3 AV-05; H, raised propareas (arrows), ELI-XYB S4-3 AV-11; I–L, pedicle foramen, just enclosed with very short intertrough, XYB S4-3 AU-07; M, N, adult with enclosed pedicle foramen, showing the successive growth of propareas at the posterior margin of the metamorphic shell (arrow), ELI-XYB S4-3 AU-01; O, enclosed pedicle foramen is mostly outside the metamorphic shell, ELI-XYB S4-3 AV-07.