Two species of sea urchins (Colobocentrotus atratus and Echinometra mathaei) commonly co-occur on wave-swept intertidal shores in the Indo West Pacific. E. mathaei is a typical spiny urchin and is confined to cavities in the rock. In contrast, C. atratus has an unusual morphology, in which the spines are much reduced, and is found on substrata fully exposed to wave-induced velocities and accele...

This study sought to understand short-term spatial changes in accretion and erosion on (experimental) carbonate blocks on three coral reefs of the Ryukyu Islands, Japan. The principal objectives were to differentiate net accretion/erosion according to season, location, depth and substrate-type. At all locations the summer season showed more positive net weight changes and higher coralline algal...

This report shows for the first time, the evidence of IL6 gene in an Echinodermata, so in an Invertebrate. It recalls also the existence of IL2 gene, we have found also in the Ophuirid: Ophiocomina nigra, the sister of the Asterid: Asterias rubens. All these animals belong to Echinodermata.

The purpose of this paper is to describe the main characteristics of macroinvertebrate species in response to environmental forcing factors. Overall, 23 species of Mollusca, 4 species of Arthropods, 3 species of Echinodermata and 3 species of Annelida were identified at the 9 sampling stations during four sampling periods. Individual species of Mollusca constituted 36.4% of the total abundance,...

Members of the phylum Echinodermata, commonly known as echinoderms, are exclusively marine invertebrates. Among the Echinodermata, sea cucumber belongs to the family Holothuroidea. The sea cucumber Stichopus (Apostichous) japonicus (Selenka) is an invertebrate animal inhabiting the coastal sea around Korean, Japan, China, and Russia. Sea cucumber has a significant commercial value, because it c...

Sea Urchin is one of the most useful tools in developmental biology studies because this organism has the simplest kind of developmental stages. We aimed to determine developmental stages and timetable of Echinometra mathaei embryo (the species of Persian Gulf). The spawning of E. mathaei was induced by 0.5M KCl injection (1ml) into the coelomic cavity. After fertilization, embryos were placed ...

The mechanisms of formation of biogenic magnesium-rich calcite remain an enigma. Here we present ultrastructural and compositional details of ossicles from the seastar Pisaster giganteus (Echinodermata, Asteroidea). Powder X-ray diffraction, infrared spectroscopy and elemental analyses confirm that the ossicles are composed of magnesium-rich calcite, whilst also containing about 0.01 % (w/w) of...

Sea Urchin is one of the most useful tools in developmental biology studies because this organism has the simplest kind of developmental stages. We aimed to determine developmental stages and timetable of Echinometra mathaei embryo (the species of Persian Gulf). The spawning of E. mathaei was induced by 0.5M KCl injection (1ml) into the coelomic cavity. After fertilization, embryos wer...

THE UTILIZATION dur ing starvation of the nutrient reserves in the gut of a temperate water sea urchin , Strongylocentrotus purpuratus, was measured by Lawrence et al. (1966) . There have been no investigations of the utilization of reserves in the gut of tropical urchins, although the level of reserves in the gut of several tropical species has been reported (Giese et al., 1964; Lawrence, 1967...