Ixodes aragaoi Fonseca, 1935

Onofrio, Valeria C., Ramirez, Diego G., Giovanni, Dalton N. S., Marcili, Arlei, Mangold, Atilio J., Venzal, José M., Mendonça, Ronaldo Z., Labruna, Marcelo B. & Barros-Battesti, Darci M., 2014, Validation of the taxon Ixodes aragaoi Fonseca (Acari: Ixodidae) based on morphological and molecular data, Zootaxa 3860 (4), pp. 361-370 : 364-367

Ixodes aragaoi Fonseca, 1935

Redescription. Male ( Figures 1–6 ). Gnathosoma : length from palpal apices to posterior margin of basis capituli 488 ± 11 (480–500). Basis capituli rectangular ( Figure 1 ), width 296 ± 22 (260–320); cornua absent. Ventral basis ( Figure 2 ) with three transversal lobes, one median, triangular, posteriorly displaced, and two lateral prominent. Palpi short and broad, total length 316 ± 27 (280–340), width 156 ± 9 (140–160); articles II and III similar in length. Hypostome length 288 ± 11 (280–300), width 180 ± 14 (160–200); with medium-sized lateral teeth, pointed, longer than median teeth; posterior crenulations arranged in lateral rows, lateral basal as a lobe, corresponding to nearly 1/3 length of hypostome.

Idiosoma : dorsal surface with long setae irregularly distributed, length from scapular apices to posterior body margin 1,712 ± 44 (1,680–1,760) maximum width 1,072 ± 52 (1,000–1,120). Scutum ( Figure 3 ) length 1,608 ± 33 (1,560–1,640), width 952 ± 33 (920–1,000); with deep punctations distributed in central region and lateral margins of median region; carinae absent; scapulae rounded; superficial cervical grooves diverging posteriorly. Ventral surface with long numerous setae; pregenital and median plates with punctations larger and deeper than those of other plates; median plate, length 816 ± 26 (780–840), width 636 ± 26 (600–660), with approximately 115 punctations; adanal plates, length 364 ± 17 (340–380), width 232 ± 18 (200–240); anal plate, length 320 ± 14 (300–340), width 264 ± 26 (220–280) ( Figure 4 ); genital aperture between coxae III; spiracular plates oval with approximately 10 rows of small goblets from macula to posterior margin; macula anterior and eccentric.

Legs: moderately long; coxa I with two spurs, internal spur very long, pointed, exceeding middle of coxa II, external spur very short and rounded, not exceeding of internal spur; coxae II–IV each with short rounded external spurs similar to external of coxa I, internal spurs absent. Tarsus I length 528 ± 18 (520–560) ( Figure 5 ); Haller’s organ as illustrated ( Figure 6 ). Tarsus IV length 464 ± 22 (440–500).

Female ( Figures 7–12 ). Gnathosoma : length from palpal apices to posterior margin of basis capituli 1,020 ± 32 (980–1,060). Basis capituli rectangular ( Figure 7 ) width 560 ± 24 (520–580); posterior margin slightly concave; porose areas separated, transversally elongated; cornua absent. Ventral basis ( Figure 8 ) narrowed posterior to auriculae, with straight posterior margin and lateral angles rounded; apparent transverse suture; auriculae short and slightly pointed. Palpi long, total length 800 ± 28 (760–820), width 216 ± 9 (200–220); article II broadly as long as article III, article length in decreasing order II (femur), III (genu), I (trochanter), IV (tibiotarsus). Hypostome length 660 ± 32 (620–700), width 196 ±17 (180–220); long and straight pointed; dental formula 4/4 for most of length, then 3/3 and 2/2 near base, corona with numerous denticles.

Idiosoma : dorsal surface with long setae. Total length from scapular apices to posterior body margin 2,224 ± 193 (2,000–2,400); maximum width 1,624 ± 46 (1,480–1,800). Scutum ( Figure 9 ) length 1,464 ± 67 (1,360–1,520), width 1,336 ± 67 (1,280–1,440); rounded, with few setae arranged on lateral margins of anterior region, few and deep punctations regularly distributed posteriorly and at lateral margins of median region; superficial cervical grooves; carinae absent; scapulae prominent. Ventral surface with long and numerous setae ( Figure 10 ); genital aperture between coxae IV; spiracular plate oval with approximately 5–6 rows of small goblets from macula to posterior margin ( Figure 11 ); macula anterior and eccentric.

Legs: moderately long; coxa I with two spurs, internal spur very long and sharp, similar to male, external spur very short as in male; coxae II–IV each with short and rounded external spurs, diminishing in size, internal spurs absent. Tarsus I 752 ± 27 (740–800), Haller’s organ with opened capsule similar to the male ( Figure 12 ); tarsus IV 664 ± 26 (620–680).

Measurements of coxa I internal spur of the types of I. pararicinus and I. aragaoi

Except for the coxa I internal spurs of I. pararicinus from Argentina, measured in this study, other measurements were not made for this species because they have already been presented in the original description ( Keirans et al. 1985). The length of the coxa I internal spur, from the posterior seta to the tip, in the male and female, is 163 ± 0.7 (162–164), and 230 ± 0.9 (229–231), respectively. In I. aragaoi the length of the coxa I internal spur, in male and female, is 188 ± 3 (185–191), and 273 ± 2 (270–274), respectively.

Phylogenetic analysis. The 16S rDNA sequences generated in the present study have been deposited in GenBank, and received the following accession numbers: KJ650032 for I. aragaoi ( 1 male and 1 female generated identical sequences); KJ650033 for I. pararicinus from Uruguay; and KJ650031 for I. fuscipes .

Phylogenetic relationships based on a partial sequence of the mitochondrial 16S rDNA gene ( Figure 13 ) segregated I. pararicinus from Argentina and Uruguay into different branches, with high divergence (8.99%). A similar divergence value was observed between I. pararicinus from Argentina and I. aragaoi (9.23%). However, I. pararicinus from Uruguay and I. aragaoi from Brazil were grouped within the same branch with low divergence values (1.59%).

Figures

FIGURE 13. Phylogenetic tree inferred from a partial sequence (435 characters, 113 parsimony informative) of the 16 S rRNA mitochondrial gene of 12 tick species of the Ixodes ricinus complex, using I. nipponensis as outgroup. Numbers at nodes are the support values for the major branches (bootstrap) derived from 500 replicates for maximum parsimony. Number within brackets are GenBank accession numbers.

FIGURES 1 – 6. Ixodes aragaoi male. 1. Gnathosoma, dorsal view, basis capituli rectangular (arrowed). 2. Gnathosoma, ventral view, lateral and ventral lobes (arrowed). 3. Scutum, deep punctations (arrowed). 4. Idiosoma ventral view, coxae I – IV, internal spur on coxa I similar to the female. 5. Tarsus I. 6. Haller’s organ, capsule (arrowed). Abbreviations: adp, adanal plate; ap, anal plate; mp, median plate. Scale-bars: 1 – 2, 75 µm; 3 – 4, 500 µm; 5, 50 µm; 6, 150 µm.

FIGURES 7 – 12. Ixodes aragaoi female. 7. Gnathosoma, dorsal view. 8. Gnathosoma, ventral view. 9. Scutum with deep punctations (arrowed). 10. Coxae I – IV, internal spur on coxa I (arrowed). 11. Spiracular plate oval. 12. Tarsus I, capsule of Haller’s organ (arrowed). Abbreviations: pa, porose area. Scale-bars: 7 – 8, 250 µm; 9 – 10, 500 µm; 11, 150 µm; 12, 250 µm.