Morel (1965a) considered Ixodes arabukiensis a probable synonym of Ixodes djaronensis, and Camicas et al. (1998) accepted that synonymy, but both species are treated as provisionally valid in Guglielmone et al. (2009, 2014), Guglielmone & Nava (2014) and here. Ixodes arabukiensis is not listed in Kolonin (2009), probably because that author considered this tick a synonym of Ixodes djaronensis.
17. Ixodes arboricola Schulze & Schlottke, 1929b. Oriental: 1) China (south); Palearctic: 1) Afghanistan, 2) Armenia, 3) Austria, 4) Azerbaijan, 5) Belarus, 6) Belgium, 7) Bulgaria, 8) China (north), 9) Croatia, 10) Czechia, 11) Denmark, 12) Egypt, 13) Estonia, 14) Finland, 15) France, 16) Georgia, 17) Germany, 18) Great Britain, 19) Hungary, 20) Israel, 21) Italy, 22) Kyrgyzstan, 23) Latvia, 24) Lithuania, 25) Moldova, 26) Mongolia, 27) Netherlands, 28) Norway, 29) Poland, 30) Portugal, 31) Romania, 32) Russia, 33) Slovakia, 34) Slovenia, 35) Spain, 36) Sweden, 37) Switzerland, 38) Turkey, 39) Ukraine (Hoogstraal 1973 a, Ogandzhanian 1984, Martyn 1988, Jaenson et al. 1994, Trilar 2004, Cringoli et al. 2005, Kolonin 2009, Paulauskas et al. 2010, Chen et al. 2010, Kiefer et al. 2010, Monerris et al. 2011, Federova 2012, Krčmar 2012, Nowak-Chmura & Siuda, 2012, Petney et al. 2012, Keskin et al. 2014, Estrada-Peña et al. 2017, Hornok et al. 2020a, Tsapko 2020, Rubel et al. 2021, Rubel & Brugger 2022, Sormunen et al. 2022).
The diagnosis of Ixodes arboricola in Clifford & Hoogstraal (1965) was considered tentative by these authors, and there are morphological differences between the redescriptions of this tick by Filippova (1977) and Clifford & Hoogstraal (1965), as well as between these and other redescriptions, such as those in Yu et al. (1997), as discussed in Guglielmone et al. (2020). Consequently, the geographic distribution of Ixodes arboricola should be regarded as provisional. This uncertainty is underscored by the fact that there are several synonyms of Ixodes arboricola, as detailed in Guglielmone & Nava (2014).
Camicas et al. (1998) treated Ixodes arboricola as a Palearctic species, but there are records published after 1998 for the Oriental Zoogeographic Region, specifically the Chinese province of Guangxi recognized in Chen et al. (2010), Zhang, G. et al. (2019), Zhang, Y.K. et al. (2019), and here. However, Zhao et al. (2021) did not include Guangxi within the range of this tick.
The presence of Ixodes arboricola in Mongolia was not recognized in Černý, J. et al. (2019), but this species is tentatively included here as a Mongolian tick.
Guglielmone et al. (2014, 2017) believed that more than one species may exist under the name Ixodes arboricola.
18. Ixodes arebiensis Arthur, 1956b. Afrotropical: 1) Democratic Republic of the Congo (Elbl & Anastos 1966 b, Kolonin 2009).
19. Ixodes ariadnae Hornok, 2014 in Hornok et al. (2014). Palearctic: 1) Belgium, 2) Germany, 3) Hungary, 4) Romania (Estrada-Peña et al. 2017, Sándor et al. 2019, Hornok et al. 2020 a, Rubel et al. 2021).
20. Ixodes asanumai Kitaoka, 1973. Oriental: 1) Japan (Ryukyu Islands); Palearctic: 1) Japan (except the Ryukyu Islands) (Kolonin 2009, Takano et al. 2014, Guglielmone & Robbins 2018).
Camicas et al. (1998) treated Ixodes asanumai as occurring only in the Oriental Region, but this tick had previously been found in the Palearctic Zoogeographic Region, as shown in Kitaoka (1973).
21. Ixodes aulacodi Arthur, 1956b. Afrotropical: 1) Benin, 2) Burkina Faso, 3) Cameroon, 4) Central African Republic, 5) Democratic Republic of the Congo, 6) Gabon, 7) Ghana, 8) Guinea, 9) Ivory Coast, 10) Nigeria, 11) Rwanda, 12) South Africa, 13) Zambia (Morel & Mouchet 1965, Aeschlimann 1967, Morel 1978, Ntiamoa-Baidu et al. 2004, Kolonin 2009, Pourrut et al. 2011, Uilenberg et al. 2013, Chitimia-Dobler et al. 2016, Horak et al. 2018).
22. Ixodes auriculaelongae Arthur, 1958c. Afrotropical: 1) Democratic Republic of the Congo, 2) Tanzania, 3) Zambia (Elbl & Anastos 1966b, Yeoman & Walker 1967, Colbo 1973, Tandon 1991, Kolonin 2009).
23. Ixodes auritulus Neumann, 1904. Australasian: 1) Australia, 2) New Zealand; Nearctic: 1) Canada, 2) USA; Neotropical: 1) Argentina, 2) Brazil, 3) Chile, 4) Colombia, 5) Costa Rica, 6) Ecuador, 7) Guatemala, 8) Panama, 9) Peru, 10) Uruguay, 11) Venezuela; remote islands: 1) Pacific Ocean Islands (south) of Chatham and Antipodes (Arthur 1960b, Wilson 1967 a, Roberts 1970, Jones et al. 1972, Keirans & Clifford 1978, González et al. 2005, Heath et al. 2011, Lindquist et al. 2016, Cicuttin et al. 2017, Carvalho et al. 2020, Guglielmone et al. 2020, 2021).
Records of Ixodes auritulus from South Pacific islands are based on Heath et al. (2011) and are named Ixodes auritulus zealandicus, most probably a species in itself (see note below).
Camicas et al. (1998, under the name Scaphixodes auritulus) and Guglielmone et al. (2014) listed this species as found in the Afrotropical Region, but records from that region have not been confirmed and the Afrotropics are excluded from the range of Ixodes auritulus (Guglielmone et al. 2020, 2021). There are also controversial records of Ixodes auritulus from the Antarctic Peninsula and South Atlantic and Indian Ocean islands that are not included in the range of this tick. Kolonin (2009) and Castrezana (2010) included Papua New Guinea and Mexico, respectively, within the range of Ixodes auritulus; however, the presence of this tick in those countries has not been confirmed, and Mexico and Papua New Guinea are provisionally excluded from its range.
Arthur (1960b), González-Acuña et al. (2005), Guglielmone et al. (2020, 2021) and others treated Ixodes auritulus as a name for a species complex, an opinion also endorsed here.
Note: the literature review for this monograph was completed on March 31, 2022. Subsequently, Apanaskevich et al. (Zootaxa, 5173, 1-73; August 5, 2022) confirmed that the name Ixodes auritulus has historically been applied to a species complex containing at least nine taxa distributed in the Australasian, Nearctic and Neotropical Zoogeographic Regions. However, these taxa are not discussed here.