Information related to the skeletal morphology of fish, especially the cranium, is still limited. It encourages researchers to conduct descriptive studies of the cranium of African catfish (Clarias gariepinus Burchell, 1822) collected from an aquaculture pond in Aceh. Each part of the cranium was digitally documented using Canon EOS 700D camera and edited using Adobe Photoshop CS6.
The study revealed that the African catfish™s cranium is identical to several fish species such as Platyclarias machadoi (Clariidae), Tor tambroides (Cyprinidae), and Kryptoglanis shajii (Kryptoglanidae). African catfish osteocranium was divided into two main parts neurocranium and splanchnocranium. The neurocranium is the portion of the skull that protects the brain and certain sense organs, while the splanchnocranium links to help the digestive and respiratory systems.
The neurocranium of the African catfish was composed of bones with a strong structure, thick and equipped with thorn-like protrusions on the dorsal part. The shape of the neurocranium of African catfish is similar to fish from the Pimelodidae family, such as Phractocephalus hemioliopterus. However, there is a difference between the Cyprinidae family, the Nemacheilidae family, and the Cichlidae family in the sense that fish from this family tend to have a non-rigid and thin with smooth surface. The morphological variation of the neurocranium of African catfish compared to another family might be closely related to the various characteristics of the habitat of fish. Pérez and Fabré revealed that the morphological differences between the neurocranium and otoliths of fish emerged as an adaptive (evolutionary) response to various environmental conditions (selective pressure) encountered. Catfish spend most of their life inhabiting the bottom layer of the waters. Furthermore, the head of catfish tended to receive intense water pressure for an extended period. Thus, catfish require a sturdy and thick neurocranium structure accompanied by small bumps on the dorsal part to reduce water pressure and mud. African catfish are known to have environmental conditions with high turbidity levels. Besides, African catfish tend to be actively foraged at night (nocturnal). This caused the African catfish’s vision system to be less developed than other sensory systems. Schmitz & Wainwright also stated that fish that foraged by not relying on the organ of vision generally had bones that makeup-less developed orbital regions.
The shape of splanchnocranium (ossa splanchnocranii) links with the feeding behavior and the respiratory system of fish. There were three regions of splanchnocranium directly related to African catfish feeding behavior: the maxillary region, the mandibular region, and the mandibular arcus region. Catfish tend to be carnivorous, so they require strong jaws with large mouth openings. During the mouth opening process, these three regions form a straight line to enlarge cavum brachialis. Thus, the process of sucking food could take place optimally. African catfish have a different respiratory organ called the arborescent organ. This organ is derived from modifying the second to fourth-gill arch to take oxygen from water and air. The presence of arborescent organs causes the African catfish™s arcus hyoideus region and the opercular apparatus to become undeveloped compared to other fish with other respiratory organs
Author: Yeni Dhamayanti
Detail information on the reseach can be viewed in:
