Particularities of the bucco-pharyngeal apparatus in Zenarchopterus kampeni (Pisces : Hemiramphidae) and their probable significance in feeding

The present study shows several new anatomical particularities of the buccal and pharyngeal parts of the halfbeak Zenarchopterus kampeni. The upper buccal jaw consists of premaxillaries and maxillaries tightly joined by ligaments. A 10degrees lowering of the mandible leads to a 30degrees elevation of the upper jaw. The adductor mandibulae is reduced to bundles A(2) and Aomega. As in the Labridae, the lower pharyngeal jaw articulates with the scapular girdle. The upper pharyngeal jaw consists of distinct second pharyngobranchials followed by the third pharyngobranchials fused into a powerful posterior component. This part fits into and slides along a longitudinal ventral gutter of the neuroranium, thanks not only to the dorsal retractor muscles but also to specific retractors of the second pharyngobranchials. The power and dentition of the pharyngeal parts contrasts with the fragility of the buccal elements.