Statolith Based Species Identification Method for Two Sepiidae Species from the Gulf of Kuwait

Abstract

El-Naggar, Marwa Abobakr, Yassien, Mohammed Hamed and Manaf Behbehani

The morphology of cephalopod statolith is closely related to its function, it is determined by the functional role of each of its parts together with complexly structured inner space of statocysts. Owing to a lack of previous reports concerning the ultra- structure and morphology of the equilibrium organs and statoliths in cephalopods of the Arabian gulf , a comprehensive study was therefore designed to explore the functional morphology of statocysts and statoliths of the broad club Sepia latimanus, and the pharaoh cuttlefish Sepia pharaonis using SEM in Kuwaiti waters. Significant differences are found in the external morphology of statoliths of the two species. The statolith of S. latimanus is typically demersal type statoliths characteristic of nearbottom decapods, while that of S. pharaonis is a pelagic type statoliths, these results demonstrate the strong impact of statolith morphology on the abundance of cephalopods and their distribution. The present study revealed the differentiation of the crystals forming the external surface of the statoliths of the two species under investigation, this surface is the site of interaction between the statolith and the statocyst. The results of this study will provide an essential basis for future investigations in the field, this may provide us with better understanding of yet unknown migration patterns of various cephalopod species.

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