HORSESHOE CRAB
Classification:
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Cheilcerata
Class: Merostomata
Order: Xiphosurida
Family: Limulidae
Species: Polyphemus
Scientific Name: Limulus cyclops
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Cheilcerata
Class: Merostomata
Order: Xiphosurida
Family: Limulidae
Species: Polyphemus
Scientific Name: Limulus cyclops
Morphology
The body of a horseshoe crab is divided into three parts the prosoma, opisthosoma and telson. The prosoma is the front part of the horseshoe crab and it combines the head and thorax under the exoskeleton. The opisthosoma is attached to the prosoma with a hinge. The shell protects the gills and two genital pores under the horseshoe crab. The top of the shell has ridges. These are locations where muscles are attached to the inside of the shell. Two large eyes are located on the prosoma, and there other light receptors all over the horseshoe crabs body. The horseshoe crab has bilateral symmetry.
Where can horseshoe crabs be found?
- The Mangrove horseshoe crab is found in Southeast Asia
- The Atlantic horseshoe crab is found along the northwest Atlantic coast and in the Gulf of Mexico
- Tachypleus gigas is found in South and Southeast Asia
- Tachypleus tridentatus is found along East Asian coasts
Horseshoe crabs are the world's oldest creatures. They are estimated to be at least 300 million years old. The earliest horseshoe crab species were crawling the Earth's coastal seas for at least 100 million years before the dinosaurs even arrived. Since that time, thousands of other species have come and gone, but horseshoe crabs have survived and today remain much as they were those millions of years ago.
Why is a horseshoe crab important?
One importance of the horseshoe crab is it's blue blood. The reason it's blood is blue is because it's copper instead of iron based like our blood. That is why it's blue instead of red. The horseshoe crab blood is used to test drugs. So if you have ever had a tetanus shot, a flu shot or any kind of shot a horseshoe crab has made it possible without you getting sick or possibly dying.
fun facts
- It has been estimated that whelk fishermen use 20,000 to 25,000 horseshoe crabs per year as bait.
- Its tail is NOT a weapon.
- Limulus has four eyes - two small, simple eyes up forward and two larger, compound eyes (much like a fly's eyes) on either side of the shell.
- Limulus has one pair of feeding legs, four pairs of walking-feeding legs, and one longer pair of walking legs that shove the body forward.
- This is a crab that isn't a crab! It is distantly related to spiders and scorpions.
Vocabulary
- Prosoma- Is the front part of the horseshoe crab and it combines the head and thorax under the exoskeleton.
- Bilateral Symmetry- Symmetrical arrangement of an organism or part of an organism along a central axis, so that the organism or part can be divided into two equal halves.
- Opisthosoma-The abdomen of a horseshoe crab.
- Telson- The tail of a horseshoe crab.
- Horseshoe Crab- large marine arthropod of the Atlantic coast of North America having a domed carapace that is shaped like a horseshoe and a stiff pointed tail; a living fossil related to the wood louse.
Resources:
- http://www.horseshoecrab.org/med/med.html
- http://en.wikipedia.org/wiki/Horseshoe_crab
- http://seagrant.gso.uri.edu/factsheets/horseshoe_crab.html