Amblyomma imitator, a New Species of Tick from Texas and Mexico, and Remarks on the Synonymy of A. cajennense (Fabricius) (Acarina-Ixodidae)

Abstract

Holotype: Female, from goat, Brownsville, Texas, February 8, 1934 (RML 10021) L. Demieville. In the Rocky Mountain Laboratory. Allotype: Male, data as for holotype. In the Rocky Mountain Laboratory. Paratypes: 3 males, 5 females, 7 nymphs with same data as holotype. 14 males, 12 females, from cow, Brownsville, Texas, May 18, 1935 (RML 11087) L. Demieville. 3 males, 7 females, 1 nymph, from man, El Baiito, near Valles, San Luis Potosi, Mexico, 1939 (RML 17459) R. Traub. Paratypes are deposited in the U. S. National Museum, Chicago Natural History Museum, Laboratorio de Entomologia de Instituto de Salubridad y Enfermedades Tropicales, Mexico, D.F., and the Rocky Mountain Laboratory. Over 700 other specimens examined, designated by the accession numbers assigned to them at the Rocky Mountain Laboratory, are as follows: 10036, 10048, 11049, 11060, 11063, 32241, 34576, 34585, 32165, 32172, 32175, 32180, 32178, 32169, 25328, 25329, 15492, 15493, 15494, 17470, 17467, 17458, 17461, 17465, 17468, 29974, 24010, 24011, 24015, 32160, 32176. These are all from Texas and Mexico, and from these hosts: man, dogs, horses, burros, cattle, goats, deer, peccary, opossum, Sciurus aureogaster, Meleagris gallopavo, Geococcyx californianus; some were from vegetation or the ground. Female: Resembles A. cajennense but tends to be smaller; differs particularly from it in lacking chitinous tubercles at the postero-internal angle of the festoons, and in details of the external genitalia. Length of holotype, excluding capitulum, 3.18; width 2.56. Length and width of largest and smallest unfed specimens seen, 3.49 by 2.67 and 2.87 by 2.15, respectively. Contour oval, broadest at about middle. Color of unfed specimens paler than usual in Amblyomma. Largest fed specimen seen is 9.74 long by 6.66 wide and both ends are equally broad. Capitulum: Length (holotype) 0.98; width of basis, 0.63. Details as in A. cajennense. Scutum: Triangular, 1.57 long by 1.70 wide (holotype); size ranges from about 1.34 by 1.52 to 1.84 by 1.90. Shape, grooves and punctations as in A. cajennense. Ornamentation variable in distinctness and extent; pattern, when well developed, as in Figure 1B, similar to that of A. cajennense, Figure 1D. Legs and Spiracular Plate: As in A. cajennense. Genital aperture: Located between coxae II as in A. cajennense. Genital apron overlaid posterolaterally on either side by a blunt flattened projection darker in color than the apron and adjacent integument, as illustrated in Figure 2A. In A. cajennense these projections are long and narrow as shown in Figure 2B. This differentiating character is easily observed in clean, unfed or fed, unmounted specimens properly lighted under 36x magnification. Male: Closely resembles A. cajennense and not always distinguishable from it with certainty but usually paler and tending to be narrower and smaller. Ornamentation variable in extent and definition; pattern, when well developed, as in Figure 1A and similar to that of A. cajennense as shown in Figure 1C. Length of allotype, excluding capitulum, 2.97; width 2.36. Largest and smallest specimens seen are 3.48 by 2.66 and 2.26 by 1.77, respectively. Nymph: Similar to A. cajennense except scutum shagreened instead of smooth and punctations somewhat larger, deeper, and more distinct.