underthehedge:

typhlonectes:

It takes guts for a sea spider to pump blood

These arthropods’ unusual digestive system can act like a heart and gills

by Susan Miller

A newfound way of delivering oxygen in animal circulatory systems depends mostly on food sloshing back and forth in the guts.

This
discovery came in sea spiders, or pycnogonids, which can look like legs
in search of a body.

Their spookily long legs hold stretches of
digestive tract, which wouldn’t fit inside the creatures’ scrap of an
abdomen. Waves of contraction sweeping up and down the leggy guts cause
blood outside the guts to move too, evolutionary physiologist Art Woods
of the University of Montana in Missoula said January 8 at the annual
meeting of the Society for Integrative and Comparative Biology. 

As lumpy
surges of partly digested food rise and fall, blood that has picked up
oxygen by diffusion whooshes to the rest of the body, Woods proposed…

(read more: Science News)

photograph: Timothy Dwyer (PolarTREC 2016), Courtesy of ARCUS

Sea spiders are just “An Arthropod but every time you look at it it gets more nonsensical”.

Seriously, they basically traded their whole body in for more leg. How many legs? Four pairs, or sometimes six why not. No body so to speak of? Just cram the digestive tract down the legs. No room for leg muscles? Don’t worry, each muscle is just like, one cell, literally one. Tiny body and super long legs how will the heart get blood going round those legs? Just, just use the fuckin digestive tract you shoved down there.

Evolution is pretty much the art of leaping from one ridiculous mistake to another, trying to stay ahead of whatever your last fuck up was. But this is bordering on something from a cartoon where a character is trying to fix a mess and every fix causes further problems that need fixing, until there’s dishes hidden under the couch, a dent in the wall hidden behind a painting and a cupboard stuffed so full it’s about to explode.