Early development of the chondrocranium in Chrysichtys auratus (Pisces, Siluriformes, Claroteidae)

The inception and development of the cartilaginous cephalis skeleton of Chrysichthys auratus is
described from hatching to about 18 days post-hatching. At hatching, no skeletal structure is
present. Not until day 3 do clearly delimited cranial primordia become apparent. As in many
siluriforms, the neurocranium is platybasic from the start, the suspensorium constitutes, with
Meckel’s cartilage and the hyoid bar, a single cartilaginous element, and the junction between
the front and rear of the neurocranium is complete on day 4. By day 8 the quadratomandibular
joint has formed and the tectum posterius has appeared. Cartilage reduction first
affects the trabecular bars, then, markedly, the visceral arches. By day 18 the braincase floor
has almost disappeared.