FOOD HABITS AND ULTRASTRUCTURE OF GASTRIC MILL OF THE GRAPSID CRAB, METOPOGRAPSUS MESSOR (FORSKAL, 1775) FROM THE RED SEA, EGYPT. | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 14, Volume 4, Issue 1, January 2000, Page 239-264 PDF (4.03 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2000.1650 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Awaad El-Sayed1; Fatma Fouda2; Ali El-Meaddawy1 | ||||
| 1Zoology Department, Faculty of Science, Al-Axhar University, Nasr City, Cairo | ||||
| 2Zoology Department, Girls College for Arts, Sciences and Education, Ain Shams University, Cairo. | ||||
| Abstract | ||||
| During the present study, the stomach contents of a medium-sized grapsid crab, Metopograpsus messor (Grapsidae, Brachyura) inhabiting different habitats (rocky, sandy-rock, and mangrove swamps) of the Red Sea (southern Aqaba Gulf) were examined by both frequency occurrence and percentage points. The results show that this species is opportunistic omnivore, with general food items consisting of algae (brown, red, green and blue green), benthic animals dominated by crustacean copepods, isopods, amphipods and other crustaceans,. in addition to foraminiferans, polychaetes and animal eggs, with few fragments of hydroids, bryzoans as well as organic debris and unidentified items. Higher plants including leaves and adventious roots of mangroves and seagrass leaves were also reported among stomach contents. Moreover, sediments were represented by considerable amounts at both different habitats and seasons. The types of foods were significantly different through various habitats and seasons. The gastric mill of the crab, which deals mainly with mechanical digestion was investigated by both light and scanning electron microscopes. It appeared as a very complex structure, composed of 6ossicles arising as internal thickening and calcification of dorsal and postero-lateral walls of the cardiac stomach. These ossicles are pterocardiac, propyloric, exopyloric, urocardiac, zygocardiac and lateral ossicles. The first three ossicles are very simple and used mainly for articulation; while the latter ones are greatly modified with conspicuous enlargement, forming a mammalian-like teeth in zygocardiac ossicle, simple ridges and denticles in urocardiac one, or with many grooves and plates provided with dense hairs and accessory spines as in lateral ossicle. All these ossicles are well articulated together, working in a regular pattern adapted to chewing, grinding, and processing of ingested food, | ||||
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