Transcript Phylum Arthropoda, Subphylum Chelicerata

Phylum Arthropoda,
Subphylum Chelicerata
• Chelicerae are pointed appendages which are used
to grasp food
• Subphylum Chelicerata includes sea spiders (class
Pycnogonida) and arachnids (class Arachnida)!
Horseshoe Crabs
• Horseshoe crabs belong to class Merostomata
(“thigh mouth”)
• Appendages used for feeding at one end, and
for swimming/locomotion at the other
• Critically important
in coastal marine
food webs
– Why?
© Steffen Foerster Photography/ShutterStock, Inc.
Horseshoe crabs
• Oldest record of horseshoe crab fossils date
back 450 million years ago
• Horseshoe crab blood contains hemocyanin to
carry oxygen; blue
• Blood contains amebocytes which release a
clotting factor when
exposed to bacteria
– Used to detect
contamination in
medications
http://www-tc.pbs.org/wnet/wp-content/blogs.dir/3/files/2008/06/590_crash_blood.jpg