Under a relatively low magnification of 193X, this scanning electron micrograph (SEM) provided a closer view of this male Dermacentor sp. tick found upon a cat in the suburbs of Decatur, Georgia, which measured approximately 3.5mm from its gnathosoma (i.e., capitulum), which is where its mouthparts are located, to the distal abdominal margin (PHIL 9961). PHIL 9959 revealed all this tick's legs, placing it into the Phylum Arthropoda, i.e., from jointed ( 'Arthro'), and legs ('poda'), as well as the Class Arachnida, for they've eight of these legs, unlike insects, which use six appendages to move about. From proximal to distal location, each leg is comprised of a coxa, trochanter 1, trochanter 2, a femur, patella, tibia, a two-sectioned tarsus, and a two-part pretarsus, i.e., a pulvillus and claw. Here we see the trochantofemoral joint of the arachnid's left 3rd leg, and the femoropatellar joint of its left 2nd leg.
CDC/ Callie Carr
November 27, 2012