Ixodoidea

Using a pin as a reference tool, this photograph depicts a dorsal view of four Amblyomma maculatum ticks. From left to right, this group of four included a larval tick, a nymph, an adult male, and at far right, an adult female. Note that the head of the pin measures just under 2mm in diameter, while its full length measures 22mm.This tick specie is a known vector for Rickettsial organisms, Rickettsia parkeri, and Ehrlichia ruminantium, formerly Cowdria ruminantium. R. parkeri is a member of the spotted fever group of rickettsial diseases affecting humans, while E. ruminantium causes heartwater disease, an infectious, noncontagious, tick-borne disease of domestic and wild ruminants, including cattle, sheep, goats, antelope, and buffalo. Each life stage depicted here, can feed on human hosts, and can be infected with Rickettsia parkeri.Created: 2008

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.Created: 2006

Under a relatively low magnification of 98X, 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 joints of the arachnid’s left 3rd and 4th legs, and the femoropatellar joints of its left 2nd and 3rd legs.Created: 2006

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.Created: 2006

Under a relatively low magnification of 95X, 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 femur, patella, and tibia of arachnid’s left 2nd and 3rd legs.Created: 2006

Under a magnification of 3206X, four times greater than PHIL 9965, this scanning electron micrograph (SEM) depicted a dorsal view 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). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Revealed in this image is the base of the hypostome, which is one of the tick’s mouthparts that acts to pierce the host skin surface, thereby, anchoring the tick to the host as it obtains its blood meal. See PHIL 9964 for another view of the foliated hypostomal surface, which begins here as small scales.Created: 2006

Under a magnification of 3206X, four times greater than PHIL 9965, this scanning electron micrograph (SEM) depicted a dorsal view 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 (seen here) (i.e., capitulum), which is where its mouthparts are located, to the distal abdominal margin (PHIL 9961). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Revealed in this image is the base of the hypostome, which is one of the tick’s mouthparts that acts to pierce the host skin surface, thereby, anchoring the tick to the host as it obtains its blood meal. See PHIL 9964 for another view of the foliated hypostomal surface.Created: 2006

Under a magnification of 801X, this scanning electron micrograph (SEM) depicted a dorsal view 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 (seen here) (i.e., capitulum), which is where its mouthparts are located, to the distal abdominal margin (PHIL 9961). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Seen clearly in this image is the base of the hypostome, which is one of the tick’s mouthparts that acts to pierce the host skin surface, thereby, anchoring the tick to the host as it obtains its blood meal. See PHIL 9964 for another view of the foliated hypostomal surface.Created: 2006

Under a magnification of 3043X, approximately 8 times greater than PHIL 9963, this scanning electron micrograph (SEM) depicted a dorsal view 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). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Seen clearly in this image is the foliate covering of the tick’s skin-piercing hypostome, which is located in what appears to be a trough between its pedipalps.Created: 2006

Under a magnification of 380X, approximately 4 times greater than PHIL 9962, this scanning electron micrograph (SEM) depicted a dorsal view 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). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Seen clearly in this image is the tick’s pedipalps, between which is located its skin-piercing hypostome and chelicerae. Note PHIL 9964 for an additional view of this region under a greater magnification.Created: 2006

Under a magnification of 97X, this scanning electron micrograph (SEM) depicted a dorsal view 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 (seen here) (i.e., capitulum), which is where its mouthparts are located, to the distal abdominal margin (PHIL 9961). Note in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Seen clearly in this image are the tick’s pedipalps between which is located its skin-piercing hypostome and chelicerae. Note PHIL 9963 and 9964 for two additional views of this region under successively greater magnification.Created: 2006

Under a magnification of 193X, four times that of PHIL 9960, this scanning electron micrograph (SEM) depicted a dorsal view 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. Note here, and more so in PHIL 9959 and 9960, that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male. In female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. Seen clearly in this image are the ridges that run along the distal abdominal border, and are known as festoons, and are one of the identifying characteristics used to classify hard, or Ixodid ticks.Created: 2006

Under a low magnification of 49X, twice that of PHIL 9959, this scanning electron micrograph (SEM) depicted a dorsal view 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. Note that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male, whereas, in female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. The ridges running along the distal abdominal border are known as festoons.Created: 2006

Under a low magnification of 23X, this scanning electron micrograph (SEM) depicted a dorsal view 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. Note that the entire dorsum of this tick’s abdomen is covered by its tough scutum, or shield, categorizing it as a male, whereas, in female Ixodid-species ticks, the scutum only partially covers the dorsal abdomen. The ridges running along the distal abdominal border are known as festoons.Created: 2006

This illustration depicts the festoons found on the abdomen of Dermacentor and Anocentor Ixodidae hard ticks.Created: 1976

This illustration depicts a female Boophilus tick from the ventral view showing its ridged palpi, and indented fore coxae.Created: 1976

This illustration depicts tick morphology associated with the presence of a laterally extended basis capituli.Created: 1976

This illustration shows an Otobius soft tick from the ventral view with its reduced hypostome and granular integument.Created: 1976

This illustration depicts the integumentary structure found on the dorsum of the Otobius and Antricola soft ticks.Created: 1976

This photograph depicted a dorsal view of an adult female western blacklegged tick, Ixodes pacificus, which has been shown to transmit Borrelia burgdorferi, the agent of Lyme disease, and Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis (HGA), which was previously known as human granulocytic ehrlichiosis (HGE), in the western United States. The small scutum, or tough, chitinous dorsal abdominal plate, does not cover its entire abdomen, thereby allowing the abdomen to expand many times when this tick ingests its blood meal, and which identified this specimen as a female. The four pairs of jointed legs, places these ticks in the Phylum Arthropoda, and the Class Arachnida.Created: 2006

This photograph depicted a dorsal view of an adult female western blacklegged tick, Ixodes pacificus, which has been shown to transmit Borrelia burgdorferi, the agent of Lyme disease, and Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis (HGA), which was previously known as human granulocytic ehrlichiosis (HGE), in the western United States. The small scutum, or tough, chitinous dorsal abdominal plate, does not cover its entire abdomen, thereby allowing the abdomen to expand many times when this tick ingests its blood meal, and which identified this specimen as a female. The four pairs of jointed legs, places these ticks in the Phylum Arthropoda, and the Class Arachnida.Created: 2006

The blacklegged ticks, I. pacificus, (depicted here), and I. scapularis, are known vectors for the zoonotic spirochetal bacteria Borrelia burgdorferi, which is the pathogen responsible for causing Lyme disease. The ticks, inoculated with the bacterium when they bite infected mice, squirrels and other small animals, subsequently pass the pathogens to their human victims when they obtain a blood meal.B. burgdorferi bacteria can infect several parts of the body, producing different symptoms at different times. Not all patients with Lyme disease will have all symptoms, and many of the symptoms can occur with other diseases as well. If you believe you may have Lyme disease, it is important that you consult your health care provider for proper diagnosis.Created: 2005

This photograph depicts a dorsal view of both a female (Lt), and male (Rt) Rocky Mountain wood tick, Dermacentor andersoni. This tick specie is a known North American vector of Rickettsia rickettsii, which is the etiologic agent of Rocky Mountain spotted fever. Note the smaller size of the female’s scutum compared to the male’s larger scutum. From the Latin word for shield, the scutum, i.e., dorsal shield, covers only a small part of the female’s dorsal surface, thereby, enabling her abdomen to expand, becoming engorged during feeding. The male’s scutum covers his entire dorsal surface, and is mottled with brown markings overall, while the female’s small scutum sports an almost entirely a cream-colored gray surface.Created: 2008

This photograph depicts a dorsal view of a male Rocky Mountain wood tick, Dermacentor andersoni. This tick specie is a known North American vector of Rickettsia rickettsii, which is the etiologic agent of Rocky Mountain spotted fever.Rocky Mountain spotted fever, like all rickettsial infections, is classified as a zoonosis. Zoonoses are diseases of animals that can be transmitted to humans. Many zoonotic diseases require a biological vector (e.g., a mosquito, tick, flea, or mite) in order to be transmitted from the animal host to the human host. In the case of Rocky Mountain spotted fever, ticks are the natural hosts, serving as both reservoirs and vectors of R. rickettsii. Ticks transmit the organism to vertebrates primarily by their bite. Less commonly, infections may occur following exposure to crushed tick tissues, fluids, or tick feces.See PHIL 10869, for a side-by-side comparative view of both a male and female D. andersoni tick.Created: 2008