First Record of the Invasive Species Indothais malayensis (Gastropoda) and New Record of Isognomon bicolor (Bivalvia) in the Mediterranean Sea

Abd Ellah, Shahenaz

doi:10.21608/ejabf.2025.450212

First Record of the Invasive Species Indothais malayensis (Gastropoda) and New Record of Isognomon bicolor (Bivalvia) in the Mediterranean Sea

Author

Shahenaz Abd Ellah

10.21608/ejabf.2025.450212

Abstract

The present study reports the occurrence of two alien molluscan species in the Egyptian Mediterranean Sea. It documents the first record of the gastropod Indothais malayensis in both the Mediterranean Sea and Egypt, as well as a new record of the bivalve Isognomon bicolor in the Mediterranean Sea and its first occurrence in Egypt. In 2024, specimens of I. malayensis and I. bicolor were manually collected during a surveillance study of rocky shore molluscs in Abu Qir Bay, Alexandria, Egypt. Specimens were found in sediments associated with rocky shores and intertidal zones, at depths ranging from 0.4 to 0.6 meters. During sampling in October 2023, January 2024, April 2024, and July 2024, approximately 312, 298, 79, and 27 individuals per square meter of I. malayensis were collected, respectively. In the same periods, 45, 9, 15, and 3 individuals per square meter of I. bicolor were recorded. All specimens were identified to the species level based on morphological characteristics of the shell.

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