Horseshoes do not have much to do to pursue your nightmares. Their hard shell hides legs and mites, they use their long, prickly tail to turn over, and they bleed the milk-blue blood. Think of less "Sebastian of the Little Mermaid" and more of "Facehugger from Alien".
But it turns out that the horseshoe crab is not a magical cartoon crustacean or alien species ̵
Because Xiphosura's blood is so sensitive to toxins, scientists also collect their blood (which is a beautiful tint of the blue sky) to be used to test contamination in such things as medical equipment. (Blood is so valuable, researchers in Florida recently contacted the public to report on the observation of horseshoe crabs that mate the next full moon. Sorry, children, it seems that Disney World will have to wait!)
Now a new research paper, published by the University of Wisconsin-Madison and first reported by National Geographic, threw horseshoe crab in a new light. Investigating the ram of the genetic material, as well as data on genome sequencing projects, the researchers traced the origin of the genus tree of a horseshoe crab
Horseshoe crabs did not develop separately to spider-like on the ground, like spiders and scorpions. They are actually classified as aquatic spider-like.
"This particular part of the tree of life was quite difficult to solve," said Chief Researcher Jesús Ballesteros of National Geographic.
"But one of the things that marveled at this analysis is that regardless of how we process the data, we have consistently shown the same results … horseshoe crabs are always enclosed inside spider-shaped [on the family tree].
If you are arachnophobic, now you can conveniently add a horseshoe crab to the list of fears.
And if you are a person with eyes, you probably can.