First comprehensive taxonomic account of Salmacis bicolor L. Agassiz in L. Agassiz & Desor, 1846 (Echinodermata: Echinoidea) from Manbar Island, Makran Coast, Pakistan

Abstract

The present study provides the first comprehensive morphological and taxonomic account of Salmacis bicolor L. Agassiz in L. Agassiz & Desor, 1846 from Pakistan, based on recently collected specimens from the intertidal rocky shore of Manbar Island along the Makran coast, Balochistan. Although earlier reports documented the occurrence of this species in Pakistan, subsequent works either omitted it or offered only photographic records without accompanying morphological descriptions. The examined specimens exhibit diagnostic characteristics consistent with global accounts of the species, including a hemispherical to subconical test; interambulacral plates with zig-zag sutures; crenate but non-perforated tubercles arranged in horizontal series; and cylindrical, finely striated spines, banded in red with yellowish, violet, or green hues, typically with red bases. These observations confirm the presence of S. bicolor along the Makran coast and constitute the first verified morphological description of the species from Pakistan. This study not only substantiates earlier fragmentary records but also contributes to the expanding baseline knowledge of echinoid diversity in the northern Arabian Sea, highlighting the need for further investigations that integrate both morphological and molecular approaches.