. Bulletin of the British Museum (Natural History) Zoology. . Fig. 13 Belodontichthys dinema: A, palatine (right) in dorsal view; B, palatine and maxillary head (anterior view of articulation); C, maxilla (right) in lateral view (LILI 89002); D, Ompok bimaculatus, palatine with maxilla (right), shown in situ with respect to 1st infraorbital (BMNH : 171-8); E, Wallago attu, palatine and maxilla (right) in articulation and bound by connective tissue (double-dashed lines) LILI 89074. a well-developed opercular condyle; ventrally, the bone is indented by the foramen for the mandibularis
. Bulletin of the British Museum (Natural History) Zoology. . Fig. 13 Belodontichthys dinema: A, palatine (right) in dorsal view; B, palatine and maxillary head (anterior view of articulation); C, maxilla (right) in lateral view (LILI 89002); D, Ompok bimaculatus, palatine with maxilla (right), shown in situ with respect to 1st infraorbital (BMNH : 171-8); E, Wallago attu, palatine and maxilla (right) in articulation and bound by connective tissue (double-dashed lines) LILI 89074. a well-developed opercular condyle; ventrally, the bone is indented by the foramen for the mandibularis branch of the hyomandibular nerve and is covered by the properculum. The quadrate is large with (in cross-section) a triangular articular condyle whose articulatory surface is deeply divided (Fig. 17A). The posteroventral surface of the quadrate is covered by the lower part of the preoperculum. There are two pterygoid bones, an extensive posterior element which contacts, respectively, the anterior and dorsoanterior margins of the hyomandibular and quadrate, and a small, oblong element ligamentously suspended between the large pterygoid and the lateral ethmoid (ppt and apt, Fig. 17A). Comparisons Compared with other members of the Siluridae, Belodontichthys has a narrower hyomandibular with a more pronouncedly concave anterior border. The longitudinal lateral crest also has a marked concave anterior margin and its ventral surface serves as the site of insertion for the levator arcus palatini muscle and origin of the inner section of the adductor mandibulae muscle. A prominent longitudinal LAP crest also occurs in Ompok (Fig. 17E) but in other Siluridae apart from Wallago it is reduced to a narrow bar. In Wallago attu the width of the crest is such that it extends forward as a long pointed lamina of bone to overlap the posterolateral face of the large pterygoid (Fig. 17E), whereas in W. leeri the crest is much narrower and more closely resembles the condition in Silurus (Fig. 17C
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