Figure 4. Comparative scheme of the anterior region of the chondrocranium of Pipa arrabali in dorsal view, at three different stages, identifying the structures that were inferred a posteriori: light pink = quadratoethmoidal process; yellow = quadratoethmoidal ligamentum; blue = ligamentum quadratoethmoidal condrified; orange = processus lateralis trabeculae; green = olfactory nerve. Circle indicates the structure that corresponds to the pars alaris of the cartilago labialis superior. A, 35027-A (SVL: 3.51 mm—Stage II-2); B, 35055-A (SVL: 3.81 mm— Stage II-3); C, 35000-A (SVL: 5.30 mm—Stage II-4). The bar corresponds to 1 mm.