A palatal bone which -- like many palatal bones -- may originally have developed as a dermal bone replacing part of the palatoquadrate, the primitive upper jaw. Like the palatine (also called dermopalatine), the ectopterygoid replaces the middle part of the autopalatine. It may be serially homologous with the palatine(s), but is somewhat specialized, being the last (most posterior in palatal view) of the series and bordering the fossa for the jaw muscles. In a typical tetrapod it abuts the palatine anteriorly, the maxilla laterally, the pterygoid or the fossa mandubuaris medially, and the fossa posteriorly. [ http://palaeos.com/vertebrates/glossary/glossaryE.html ]