GROSS ANATOMY OF THE SPLANCHNOCRANIUM IN GREEN-WINGED MACAW

Abstract

A study was conducted on the gross features of the splanchnocranium of eight year old male Green-winged macaw and their morphological peculiarities were correlated with its possible functions. The horizontal plate of ethmoid was well developed and broad. The lacrimal was very large and the orbit was completely ringed with bone. The steeply down curved premaxilla with its hooked tip gave the distinctive character to the broad-based bill. The external nares were small and circular. The maxilla formed movable articulation with both the palatine and zygomaticus. The zygomaticus was rod like and formed a movable articulation with the maxilla cranially and quadrate caudally. The paired palatines were vertical in position and formed a strong bone of the upper jaw. The pterygoid was a rod like bone which articulated with only the palatine cranially and quadrate caudally. The quadrate was semicircular. The mandible was horse-shoe shaped with wide vertical thickened rami. The dentine presented a toothed-cutting edge to which the horny beak was attached.  The fronto-nasal synovial hinge joint was highly mobile and supported the well developed prokinesis seen in this bird.