Looks like a mithrax. Don't they come in other colors besides *emerald* ?
Body shape is the same.
http://z.about.com/d/saltaquarium/1/0/G/A/kcollinsemeraldcrab_400.JPG" alt="" />
Check [IMG]http://images.google.com/imgres?imgurl=http://www.bio.georgiasouthern.edu/GR-inverts/images/Mithraxhispidus4.jpg&imgrefurl=http://www.bio.georgiasouthern.edu/GR-inverts/grlist.html%3Fspp%3DMithraxhispidus%26filaindex%3D1&h=375&w=500&sz=46&hl=en&start=17&um=1&tbnid=vM0H2olrTYB-_M:&tbnh=98&tbnw=130&prev=/images%3Fq%3Dred%2Bmithrax%2Bcrab%26um%3D1%26hl%3Den%26rls%3DGGLG,GGLG:2005-31,GGLG:en%26sa%3DN">this link</a>
[IMG]http://www.bio.georgiasouthern.edu/GR-inverts/images/Mithraxhispidus1.jpg alt="" />