Assertion: american horseshoe crab | /r/HasProperty | valuable keystone species
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text: The American horseshoe crab (Limulus polyphemus) is a valuable keystone species distributed across the Atlantic Coast of the United States and the Gulf of Mexico (Botton and Haskin, 1984; Botton and Ropes, 1989; Walls et al., 2002; Botton, 2009; Sekiguchi and Shuster, 2009).