Application of Calcareous Spicules for the Identification of Sea Cucumbers in the Rocky Shores of Northern Persian Gulf

Abstract

Sea cucumbers as a large group of marine invertebrates have traditionally been demanded as a food with high nutritional value and for medicinal aims in Asia and the Middle East for many years. To identify and compare sea cucumber species in the tidal rocky northern coast of the Persian Gulf, samples were collected from six stations in the four seasons. Based on the results of morphological and microscopic aspects, two sea cucumber species were identified including, <em>Holothuria parva</em> and <em>Holothuria arenicola</em> from Holothuriidea, Echinodermata. Comparison based on the calcareous structures (spicules or calcareous ossicles), is an important key in the identification, as it displays obvious differences between both species. The most common type of spicule of <em>H. parva</em> was various forms of rod shape, and for <em>H. arenicola</em> was related to Buttony spicules. Overall, our results indicated that skeletal microscopic structure can be used in the taxonomy of sea cucumbers, and also established the important role of calcareous spicules as an identification key to distinguish sea cucumber species.