First record of the alpheid shrimp Arete dorsalis (Decapoda: Alpheidae) associated with the sea urchin Echinostrephus molaris from the Makran Coast, Pakistan

Abstract

The study reports the first occurrence of Arete dorsalis Stimpson, 1860 from Pakistan, based on four specimens collected on 14 December 2024 from Garyan Beach, Jiwani, along the Makran Coast. The shrimp was found living among the spines of the echinoid Echinostrephus molaris, representing the first documented association between these two species in the northern Arabian Sea. Morphological examination of all collected individuals showed complete conformity with published descriptions of A. dorsalis, confirming the identification with confidence. This discovery extends the species known distribution within the Indo-West Pacific and emphasizes the role of echinoid microhabitats in supporting cryptic alpheid diversity. The present finding contributes to the knowledge of Pakistan's marine decapod fauna and highlights the need for targeted surveys of host-associated organisms to better document the region's biodiversity.