M. Aminur Rahman and Tsuyoshi Uehara (2004) Interspecific hybridization and backcrosses between two sibling species of Pacific sea urchins (genus Echinometra) on Okinawan Intertidal Reefs. Zoological Studies 43(1): 93-111. Four genetically divergent Pacific sea urchins belonging to the genus Echinometra occur sympatrically and abundantly along the coast of Okinawa Island. Among them, the 2 most...

Bindin, a protein involved in sea urchin sperm-egg recognition and adhesion, is under positive selection in genera with sympatric species but evolves neutrally in genera in which all species are allopatric. This pattern has led to suggestions that reinforcement may be the source of the observed selection. Reproductive character displacement, or increased divergence of reproductive characters in...

Bindin is a gamete recognition protein known to control species-specific sperm-egg adhesion and membrane fusion in sea urchins. Previous analyses have shown that diversifying selection on bindin amino acid sequence is found when gametically incompatible species are compared, but not when species are compatible. The present study analyzes bindin polymorphism and divergence in the three closely r...

Abstract : Sea urchin (Echinometra mathaei) contains a compound of Echinochrome A, which is polyhydroxy naphthoquinone that known to be potential antioxidant. The antioxidant effect correlated with the antidiabetic activity associated oxidative stress conditions. aim this study was determine 70% Ethanol Extract sea on blood glucose levels in alloxan induced rats. This research an experimental u...

Species of the sea urchin genus Echinometra found on the two coasts of Panamá are recently diverged and only partially isolated by incomplete barriers to interspecific fertilization. This study confirms previous work that revealed incompatibility between the eggs of the Atlantic E. lucunter and the sperm of the other two neotropical species, whereas eggs of its sympatric congener E. viridis and...

Marine organisms exhibit substantial life-history diversity, of which egg size is one fundamental parameter. The size of an egg is generally assumed to reflect the amount of energy it contains and the amount of per-offspring maternal investment. Egg size and energy are thought to scale isometrically. We investigated this relationship by updating published datasets for echinoderms, increasing th...

Although eyes are generally considered necessary for image resolution, a diffuse photoreceptive system with directional sensitivity may also have this ability. Two species of the echinoid genus Echinometra were tested for spatial vision by examining their ability to locate and move towards targets of different sizes. The echinoids were significantly oriented (P<0.0001) towards a target with an ...