horseshoe crab
Ancient marine arthropod
A horseshoe crab is a marine arthropod with a hard, horseshoe-shaped shell and a long, pointed tail.
Despite the name, it's more closely related to spiders and scorpions than to true crabs.
Horseshoe crabs have existed for hundreds of millions of years with little evolutionary change.
Their blue, copper-based blood is used in medical testing for bacterial contamination.
Mid-Atlantic coastal estuary
- estuaryTidal mixing zone
- intertidalZone between high and low watermarks
- shorelineLand-water boundary
- brackishMildly salty water
Atlantic coast · Gulf of Mexico · sand flats · tidal · coastal · benthic · shallow water · mudflat
Protective dorsal exoskeleton
- compound eyesMulti-lensed visual organs
- chitinArthropod shell polymer
- exoskeletonExternal skeletal structure
- moltingPeriodic shedding of covering
segmented · photoreceptors · ventral · dorsal · shell · cephalothorax
Organism unchanged since prehistory
- ancientVery old indeed
- primordialExisting from the start
- ancestralOf one's forebears
- evolutionSpecies changing over generations
survivor · relic · extant · Paleozoic · Ordovician · unchanged · timeless · trilobite
Aristocratic descent
- coagulationLiquid solidifying into mass
- pharmaceuticalManufactured medicinal compound
- vaccine safetyProtection from immunization risks
- bacterial contaminationHarmful microbes present
pyrogen · FDA · immunology
Releasing eggs to reproduce
- shorebirdsCoastal avian foragers
- eggsReproductive cells in shells
- migrationMovement to new territory
- conservationPreventing waste or loss
threatened · overharvesting · bait · whelk · food web · keystone · nesting · full moon
Delaware Bay
Mid-Atlantic coastal estuary
- estuaryTidal mixing zone
- intertidalZone between high and low watermarks
- shorelineLand-water boundary
brackish · Atlantic coast · Gulf of Mexico · sand flats · tidal · coastal · benthic · shallow water · mudflat · mangrove
carapace
Protective dorsal exoskeleton
- compound eyesMulti-lensed visual organs
- chitinArthropod shell polymer
- exoskeletonExternal skeletal structure
molting · segmented · photoreceptors · ventral · dorsal · shell · cephalothorax
living fossil
Organism unchanged since prehistory
- ancientVery old indeed
- primordialExisting from the start
- ancestralOf one's forebears
evolution · survivor · relic · extant · Paleozoic · Ordovician · unchanged · timeless · trilobite · lineage
blue blood
Aristocratic descent
- coagulationLiquid solidifying into mass
- pharmaceuticalManufactured medicinal compound
- vaccine safetyProtection from immunization risks
spawning
Releasing eggs to reproduce
- shorebirdsCoastal avian foragers
- eggsReproductive cells in shells
- migrationMovement to new territory
conservation · threatened · overharvesting · bait · whelk · food web · keystone · nesting · full moon · spring tide
- Horseshoe Crabs
- Merostomessea scorpion, sea scorpions
- animalscat, dog, bird, fish, cow
- ocean lifeocean, sea, sea creatures, shark, sea life
- sea lifeshark, whale, dolphin, salmon, jellyfish
- arthropodsarthropod, arthropods, Arthropoda, insects, insect
horseshoe crabblue crab
Swimming crab, Atlantic coast
king crab · Dungeness crab · lobster · crayfish · shrimp
crabby, crabs, horseshoe, crabbed, horseshoes, crabbing, crabwise, horseshoeing, horseshoed