New Species and Records of Scale Mites (Acariformes: Pterygosomatidae) from Geckos (Squamata: Gekkonidae and Caprodactylidae)

Two new species of pterygosomatid mites parasitizing geckos of the families Gekkonidae and Caprodactylidae are described: Geckobia africana n. sp. from Cnemaspis africana (Werner) from Tanzania and Geckobia milii n. sp. from Underwoodisaurus milii (Bory De Saint-Vincent) from Australia. The former species is the most similar to Geckobia loricata Berlese, 1892, but differs by the presence of the propodonotal shield reduced to small platelets, slender and blunt-pointed setae in the posterolateral part of the idiosomal venter and the absence of thick serrate ventral setae in posterior part of the idiosoma. For the latter species and Geckobia simplex Hirst, 1926, a new species group is established based on the analysis of chaetotaxy of legs I–IV. Mites of this new species group differ from the indica group by the presence of five setae on tibiae I–III and setae l'GI, l”GIV, dFI, dFII, and lFIII. Species of the genus Geckobia are recorded from hosts of the genera Cnemaspis Strauch and Underwoodisaurus Wermuth for the first time.


Introduction
Mites of the family Pterygosomatidae Oudemans, 1910 (Acariformes: Prostigmata), are one of the most diverse group of permanent parasites of reptiles. They are represented by highly specific (mono-or stenoxeous) ectoparasites of lizards (Squamata: Sauria), with the exception of Geckobia enigmatica Bertrand and Pedrono, 2000, found on tortoises (Testudines: Testudinidae) [1], and species of the genus Pimeliaphilus Trägårdh, 1905, found on terrestrial arthropods [2]. To date, the family Pterygosomatidae includes 182 species grouped into nine genera recorded from all zoogeographical regions, except for the Antarctica [3,4].
Within the Pterygosomatidae the genus Geckobia Mégnin, 1878, is the most species-rich with 73 species and subspecies. About two-thirds of the species are arranged into four species groups based on a trochanter-tibia chaetotaxy of legs I-IV [4,5], i.e., latasti, haplodactyli, ovambica, and indica, and into groups 0, j based on differences in a tarsal chaetotaxy of legs I [4][5][6]. However, about one-third of the species of the genus Geckobia is not assigned to any of the groups due to their unique morphological characters or vague descriptions.
Below, I describe two new species of the genus Geckobia from the infraorder Gekkota: Geckobia africana n. sp. found on African gecko Cnemaspis africana (Werner) (Gekkonidae) from Tanzania and Geckobia milii n. sp. associated with thick-tailed gecko Underwoodisaurus milii (Bory De Saint-Vincent) (Carphodactylidae) from Australia. According to the leg chaetotaxy pattern, the former species belongs to Geckobia group 1 established by Jack [5] (the latasti group of Fajfer [4]) whereas for the latter species and Geckobia simplex Hirst, 1926, I propose a new species group based on its unique morphology. Species of the genus Geckobia  are recorded herein from hosts of the genera Cnemaspis and Underwoodisaurus for the first time.

Materials and Methods
All mites were collected form geckos preserved in 70% ethanol in the Zoological Museum, University of Copenhagen, Denmark. The mites, before mounting in Hoyer's medium, were cleared and softened in Nesbitt's solution at 50 ∘ C for 1-3 hours. Then, the mites were studied using the light microscope Olympus BH-2 with differential interference contrast (DIC) illumination and drawings were made using a camera lucida drawing attachment. All measurements are given in micrometres as the data for the holotype followed by the ranges for the paratypes. Nomenclature of the leg and idiosomal setae follows Grandjean [7,8], and names of the palpal setae follow Grandjean [9] as adapted to the family Pterygosomatidae by Bochkov & OConnor [10]. The scientific names of the lizards follow Uetz and Hošek [11].
Specimen depositories and reference numbers are cited using the following abbreviations: ZMUC Etymology. The species name is derived from the species name of the host and is a noun in apposition.
Differential Diagnosis. This new species is the most similar to Geckobia loricata Berlese, 1892 described from Tarentola mauritanica (Linnaeus) (Gekkota: Phyllodactylidae) [12]. In females of both species the eyes are present, the setation of tibiae-coxae I-IV and tarsi I-IV is the same and the scale-like Remarks. The species of the simplex group are the most similar to the indica group from Gekkonidae from South Africa [5]. In females of both groups, the shape of the idiosoma is nearly circular, the arrangement of dorsal idiosomal setae is very similar, and setae dF are stout and dG filiform. The simplex group differs from the indica group by the following features. In females of the simplex group five setae on tibiae I-III are present and setae l'GI, l"GIV, dFI, dFII and lFIII are present, whereas in females of the indica group, four setae on 6 BioMed Research International Etymology. The species name is derived from the species name of the host and is a noun in apposition.
Differential Diagnosis. This new species is the most similar to Geckobia simplex Hirst, 1926 described from Hemidactylus leschenaultia Duméril & Bibron (Gekkonoidea: Gekkonidae) from India [13]. In females of both species, the idiosoma is nearly circular in shape and almost as wide as long, the propodonotal shield is present, the ventral setae are slender; the setation of tibia-trochanter IV and tarsi I-IV is the same. This new species differs from G. simplex by the following features: the propodonotal shield is triangular with slightly concave anterior margin and bears 10 setae, the eyes are absent, the dorsal anterior setae are much shorter than the posterior setae and seta a" of tarsi I is present. In G. simplex, the propodonotal shield is reniform with concave the posterior margin and bears about 36 setae, the eyes are present, the anterior dorsal setae are almost as long as the posterior setae, and seta a" of tarsi I is absent.

Data Availability
The data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest
The author declares that they have no conflicts of interest.