Rocky Mountain wood tick
Dermacentor andersoni
''Dermacentor andersoni'', commonly known as the Rocky Mountain wood tick, is a species of tick. It can cause tick paralysis. This tick is well known as a vector of the Rocky Mountain spotted fever rickettsia in the northwestern U.S. and Canada, the Colorado tick fever virus, and the bacteria which causes tularemia .
Diagnostic features:
* The larva only has three pairs of legs.
* The nymph has four pairs.
* A single pair of spiracular openings are seen close to the coxae of the fourth pair of legs .
* A terminal capitulum is visible from above in all hatched stages.
* A large sclerite called the scutum is present dorsally behind the capitulum. The scutum almost entirely covers the back of the male, but only partly covers the back of the female.
* Eyes, if present, are on the scutum.
* Sexual dimorphism in size and colour is frequent. The female is often larger.
* The posterior margin of opisthosoma is usually subdivided into sclerites called festoons.
* The pedipalps are rigid along the chelicerae, and are not leg-like.
Diagnostic features:
* The larva only has three pairs of legs.
* The nymph has four pairs.
* A single pair of spiracular openings are seen close to the coxae of the fourth pair of legs .
* A terminal capitulum is visible from above in all hatched stages.
* A large sclerite called the scutum is present dorsally behind the capitulum. The scutum almost entirely covers the back of the male, but only partly covers the back of the female.
* Eyes, if present, are on the scutum.
* Sexual dimorphism in size and colour is frequent. The female is often larger.
* The posterior margin of opisthosoma is usually subdivided into sclerites called festoons.
* The pedipalps are rigid along the chelicerae, and are not leg-like.
