Search

The species Ixodes aragaoi Fonseca was described as Ixodes ricinus aragaoi, and later placed in synonymy with Ixodesaffinis. However, this synonymy was rejected and the subspecies was elevated to species, and named as I. aragaoi. Someresearchers did not consider the validity of I. aragaoi and maintained the synonymy proposed until 1998 when I. aragaoiwas revalidated, and it was suggested that Ixodes pararicinus could be a synonym. The aim of this study was to confirmthe taxonomic validity of I. aragaoi by means of redescription of adults and molecular analysis. Morphological studieswere performed by optical and scanning electron microscopy; types of I. aragaoi were compared with those of I. pararicinusfrom Argentina, and also with material of I. pararicinus from Uruguay and I. affinis from the United States. Mitochondrial16S rDNA sequences were obtained for determining phylogenetic relationships based on maximumparsimony. Morphological and molecular differences between I. aragaoi, I. pararicinus from Argentina, and I. affinis confirmthe validity of the first each of these species. The morphological similarities of I. pararicinus from Uruguay with I.aragaoi, and the small distance of nucleotide sequences between them, confirm that the Uruguayan ticks are in fact I. aragaoiand expand the geographical distribution of this species. Based on the specimens of Ixodes examined in the presentstudy, from the same locality of the types of I. ricinus rochensis in Uruguay, we agree with the synonymy of this subspecieswith I. aragaoi as previously reported. Finally, our analyses indicate that both I. aragaoi and Ixodes fuscipes, anotherSouth American tick species, belong to the I. ricinus complex, currently composed of 19 species. Fil: Onofrio, Valeria C.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil Fil: Ramirez, Diego G.. Universidade de São Paulo; Brasil Fil: Giovanni, Dalton N. S.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil Fil: Marcili, Arlei. Universidade de São Paulo; Brasil Fil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina Fil: Venzal, José M.. Universidad de la República; Uruguay Fil: Mendonça, Ronaldo Z.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil Fil: Labruna, Marcelo B.. Universidade de São Paulo; Brasil Fil: Barros-battesti, Darci M.. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; Brasil

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 16 S rDNA sequences generated in the present study have been deposited in GenBank, and received the following accession numbers: KJ 650032 for I. aragaoi (1 male and 1 female generated identical sequences); KJ 650033 for I. pararicinus from Uruguay; and KJ 650031 for I. fuscipes. Phylogenetic relationships based on a partial sequence of the mitochondrial 16 S 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%)., Published as part of Onofrio, Valeria C., Ramirez, Diego G., Giovanni, Dalton N. S., Marcili, Arlei, Mangold, Atilio J., Venzal, Jos�� M., Mendon��a, 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, pp. 361-370 in Zootaxa 3860 (4) on pages 364-367, DOI: 10.11646/zootaxa.3860.4.4, http://zenodo.org/record/229298, {"references":["Fonseca, F. (1935) Notas de Acareologia XV. Ocorrencia de sub-especie Ixodes ricinus (L., 1758) no Estado de Sao Paulo (Acarina, Ixodidae). Memorias do Instituto Butantan, 9, 131 - 135.","Keirans, J. E., Clifford, C. M., Guglielmone, A. A. & Mangold, A. J. (1985) Ixodes (Ixodes) pararicinus, n. sp. (Acari: Ixodoidea: Ixodidae), a South American cattle tick long confused with Ixodes ricinus. Journal of Medical Entomology, 22, 401 - 407."]}