Under a high magnification of 3862X, this scanning electron micrograph (SEM) depicted the recessed base of a singe seta, or 'hair' emanating from the dorsum of an unidentified 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. Setae are chitinous exoskeletal adnexae which are sensorial in nature, sensing environmental changes in temperature, movement, i.e., wind, and chemistry, i.e., pheromones.
CDC/ Callie Carr
November 27, 2012