Fig. 2.

Three-dimensional reconstruction of the cranial cartilages of a stage 46 Xenopus laevis larva in frontal view. The unique infrarostral (ir) and suprarostral (sr) cartilages support the lower and upper jaw, which are composed of Meckel’s cartilage (mc) and the palatoquadrate (pq). The infrarostral cartilages articulate over a novel intramandibular joint with Meckel’s cartilage in the lower jaw and the suprarostral cartilages are fused with the cornua trabeculae (ct) in the upper jaw of X. laevis. In other frog larvae (such as Bombina orientalis), the suprarostral cartilages form separate cartilages that articulate rostrally with the trabecular horns. Cartilage: ct, cornua trabecula (trabecular horn); ir, infrarostral; mc, Meckel’s cartilage; pq, palatoquadrate; sr, suprarostral.