A systematic revision of the genus Neopterygosoma Fajfer, 2019 (Acariformes: Pterygosomatidae) with the description of a new species

A systematic revision of the scale mites of the genus Neopterygosoma Fajfer, 2019 (Acariformes: Pterygosomatidae) formerly placed in the genus Pterygosoma Peters, 1849, is presented. Two new natural species groups are established: the chilensis group for species found on Chilean liolaemid lizards (Sauria: Liolaemidae) and the patagonica group for N. patagonica (Dittmar de la Cruz, Morando & Avila, 2004) found on several Liolaemus spp. from Argentina. A neotype of N. patagonica is designated. A leg chaetotaxy model for tarsi-coxae I–IV is proposed for the genus. A key to all species of Neopterygosoma is provided and a full list of Neopterygosoma spp. with their updated host associations and distribution data is compiled. Additionally, a new species, N. schroederi n. sp. found on Liolaemus schroederi Müller & Hellmich, is described, including for the first time, description and illustrations of the immature stages of a species of Neopterygosoma.

Mites of the genus Neopterygosoma Fajfer, 2019 are associated with lizards of the genus Liolaemus (Sauria: Liolaemidae), and until recently they were placed in the genus Pterygosoma Peters, 1849 (see . In 2019, Fajfer reconstructed the phylogeny of the genus Pterygosoma based on the external morphology of the species using modern phylogeny methods (i.e. maximum parsimony and implied weighting) (Fajfer, 2019). As a result, the new genus Neopterygosoma was created for mites associated with South American lizards (Liolaemidae: Liolaemus). Currently, the genus includes six monoxenous species found on Chilean liolaemids, and one oligoxenous species, N. patagonica Dittmar de la Cruz, Morando & Avila, 2004, observed on several Liolaemus spp. (see . Until now, all the species descriptions were based solely on females, whereas immatures and males were not found. This paper describes Neopterygosoma schroederi n. sp. found on Liolaemus schroederi Müller & Hellmich (Sauria: Liolaemidae). The deutonymph, protonymph and larva are described for the first time for a species of the genus Neopterygosoma. The diagnosis for the genus is provided in Fajfer (2019), therefore it is not repeated here. However, two natural species groups are established for the genus and the updated diagnoses of all species are proposed. Additionally, a neotype is designated for N. patagonica. The leg chaetotaxy model for the genus is presented and a key to the species of Neopterygosoma is constructed. A full list of host-parasite associations is compiled.

Collection of material
The type-material of Neopterygosoma spp. was loaned from the AMU (Adam Mickiewicz University in Poznań, Poznań, Poland), ZISP (Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia) and ZMUC (Zoological Museum, University of Copenhagen, Copenhagen, Denmark). The new material used in this study was taken from dead lizards kept in jars with 70% ethanol in the ZSM (Bavarian State Collection of Zoology, Munich, Germany) and the NHM (Natural History Museum, London, UK). Each lizard's body was completely and carefully checked for mites under a dissecting microscope (Fig. 1).

Technique of slide mounting
All mites were collected from the lizard specimens kept in the institutions mentioned above and most of the loaned type-specimens were preserved in 70% ethanol. Then, the mites were cleared and softened in Nesbitt's solution at 45°C for 1-2 h and mounted in Hoyer's medium on a glass slide using the standard method (Krantz & Walter, 2009). The prepared slides were dried with the thermostat set at 50-55°C for 7-10 days, and studied using the microscope Olympus CKX41 with the Olympus cellSens Standard 1.16 software.

Terminology
The names of the leg and idiosomal setae in species descriptions follow Grandjean (1939Grandjean ( , 1944 as described by Norton (1977), while the names of the palpal setae follow Grandjean (1946). Grandjean's nomenclature was applied to the family Pterygosomatidae by Bochkov & OConnor (2006).
The scientific names of the lizards follow Uetz et al. (2019).
Family Pterygosomatidae Oudemans, 1910Genus Neopterygosoma Fajfer, 2019 Species group chilensis Diagnosis Body much wider (1.5-1.8 times) than long. Second pair of legs discernible shorter than others. Posteromedial part of idiosoma with several pairs of dorsomedian setae dm. Peripheral setae numerous and much longer than dorsal setae and situated medially and laterally. Leg setae l'GIV present. Setae tc' and tc'' of legs II-IV serrate.
Microhabitat: Under the ventral and lateral scales of the head, belly, and tail.  . A, Ventral view; B, Ventral view of the head and neck; arrow indicates mites under the scales; C, A single specimen under the host scale. Scale-bar: C, 1000 lm Distribution and host range: This group is associated with tree lizards of the genus Liolaemus (Sauria: Liolaemidae) from Chile. Species included: Neopterygosoma chilensis , N. cyanogasteri , N. formosus , N. levissima , N. ligare , N. ovata , N. schroederi n. sp. (

Diagnosis
Female [Based on the holotype, 1 paratype and 5 nontype females; Figs. 2, 3.] Gnathosoma. Fixed cheliceral digit short and with spinous process. Setae dF and dG serrate. Idiosoma 830-965 long, 1,280-1,520 wide. Antero-lateral part of dorsum with c.68 plumose setae grouped in cluster; setae increasing in length from anterior to posterior part of this cluster. Lateral to this cluster situated c.170-200 pairs of plumose setae. Among them 1 very long seta, 120 long, present on each lateral margin. About 20 pairs of serrate setae located anterior to each side of pseudanal area present. Lateral parts of idiosoma with slightly apically expanded setae. Peripheral series represented by 13 pairs of apically expanded setae. Venter with 12-18 pairs of plumose setae vm located anterior to genital area. Lateral parts covered with 39-42 pairs of setae increasing in length from ventral to lateral part of idiosoma. Shorter setae plumose, longer setae serrate at distal part. Peripheral series represented by 10-13 pairs of slightly serrate setae. Genital series represented by slightly serrate setae g1 and 5 pairs of pseudanal setae ps. Legs chaetotaxy is provided in Table 1. Coxal setae 3a filiform. Setation of tarsi I-IV is given in Table 2. Setae tc' and tc'' of legs II-IV serrate. All setae a' and a'' smooth, u' and u'' pectinate, vs' and vs'' bipectinate.
Plumose setae 17-21 pairs, located anterior to each side of pseudanal area. Postero-lateral part of idiosoma with 15 pairs of apically serrate setae. Peripheral series represented by 12-13 pairs of distally serrate setae. Venter with 14-18 pairs of setae vm, located anterior to genital area. All setae vm serrate, except for 1 pair of filiform setae situated laterally to genital area. Peripheral part of body with 20-25 pairs of postero-lateral setae and 9-10 pairs of peripheral slightly serrate setae situated posteriorly. Genital series represented by smooth setae g1 and 5 pairs of pseudanal setae ps. Legs chaetotaxy as in ovata group (Table 1). Coxal setae 3a slightly serrate. Setation of tarsi I-IV as in Table 2. Setae tc' and tc'' of legs II-IV slender and serrate only at distal margins.

Remarks
In the original description of the species ) some inaccuracies are mentioned, i.e. eyes are marked as absent but they are present, setae a' and a'' of tarsi I are marked as eupathidia but they are simple, setae it' and it'' are marked as simple but they are eupathidia.   Table 2, but additional seta present on tarsus IV.

Remarks
In the original description of the species ) some inaccuracies are mentioned, i.e. eyes are marked as absent but they are present, setae a' and a'' of tarsi I are marked as eupathidia but they are simple, setae it' and it'' are marked as simple but they are eupathidia.  Table 2.

Remarks
In the original description of the species ) some inaccuracies are mentioned, i.e. eyes are marked as absent but they are present, setae a' and a'' of tarsi I are marked as eupathidia but they are simple, setae it' and it'' are marked as simple but they are eupathidia.   (Table 1). Coxal setae 3a slightly serrate. Ventral setae of leg I serrate only at distal tip. Setation of tarsi I-IV as in Table 2.

Remarks
In the original description of the species ) some inaccuracies are mentioned, i.e. eyes are marked as absent but they are present, setae a' and a'' of tarsi I are marked as eupathidia but they are simple, setae it' and it'' are marked as simple but they are eupathidia.

Diagnosis
Female [Based on the holotype and 1 paratype; Fig. 12.] Gnathosoma. Swollen, proximal part of cheliceral base shorter than slender distal part. Palpal femur with serrate seta dF, palpal genu with seta dG serrate only at distal part. Subcapitular setae n smooth. Idiosoma 620-650 long, 1,080-1,090 wide. Dorsum. Antero-medial part with c.90 setae grouped in cluster. Lateral to this cluster, c.150 setae present on each side. Among these setae 2-3 longer setae, 85 long, present on each lateral margin of dorsum. Plumose setae, 17-21 pairs, located anterior to each side of pseudanal area. Postero-lateral part of idiosoma with setae slightly expanded on tips. Peripheral series represented by 12 or 13 pairs of setae, discernibly serrate only distally. Venter with 10-13 pairs of finely serrate setae vm located anterior to genital area. Peripheral part of idiosoma with 24-27 pairs of postero-lateral slightly plumose setae and 15 pairs of weakly serrate setae situated posteriorly. Genital series represented by slightly serrate setae g1 and 5 pairs of pseudanal setae ps. Legs chaetotaxy as in Table 1, coxae with additional setae 1a. Setae 1a and 3a situated on intercoxal area. Coxal setae 3a slightly serrate. Ventral setae of legs I almost filiform, with barely discernible serration. Setation of tarsi I-IV as in Table 2.

Remarks
In the original description of the species ) some inaccuracies are mentioned, i.e. eyes are marked as absent but they are present, setae a' and a'' of tarsi I are marked as eupathidia but they are simple, setae it' and it'' are marked as simple but they are eupathidia.

Species group patagonica
Diagnosis: Body circular, only 1. Peripheral series represented by 2 pairs of setae, located near genital region. Venter with 3-6 pairs of slightly serrate setae vm. Peripheral part of body with about 9-13 pairs of postero-lateral plumose setae and 4-6 pairs of posterior plumose setae. Genital series represented by 1 pair of slightly serrate setae g1 and 4 pairs of serrate pseudanal setae ps. Chaetotaxy of legs given in Table 1. Coxal setae 3a and 3d slightly serrate. All setae on each podomere slender and slightly plumose, except for thick and plumose setae dFI-IV. Setation of tarsi I-IV as in Table 2.

Remarks
In accordance with Article 75.3 of the International Code of Zoological Nomenclature (ICZN 1999(ICZN , 2012, I designated one of the female specimens as a neotype of Neopterygosoma patagonica for the purpose of clarifying the taxonomic status of the species. Originally, this species was insufficiently described by Dittmar de la Cruz et al. (2004). The authors in their type-series included five males (all designated as holotypes) and five females; no data about their exact localities were provided. These specimens were deposited at the Insect Genomics Laboratory, Brigham Young University, Provo, Utah, USA, but to my knowledge, none of the original type-series from this collection are extant (Dittmar de la Cruz, personal communication). Then, a thorough redescription of the species was made by Fajfer (2014); however, no neotype was designated by the author. Therefore, based on the close morphological similarity of the newly collected mites and the specimens redescribed by Fajfer (2014) to the original description of the species (Dittmar de la Cruz et al., 2004), I designate a neotype (Reg. no. UKSW-PTE2.1) and present a diagnosis of the species above.
Key to species of Neopterygosoma Fajfer, 2019 1a Body much wider than long (1.5-1.8 times). Second pair of legs discernibly shorter than others. Peripheral setae much longer than dorsal setae situated medially and laterally. Leg setae l'GIV present ……………………... 2 (chilensis group) 1b Body only slightly wider than long (1. Fixed cheliceral digit spinous ……………… ……………………………….. N. cyanogasteri 5b Fixed cheliceral digit reduced to rounded structure ……………….…………………………. 6 6a Coxal fields I with 2 setae. Gnathosoma situated apically ……………………………………… 7 6b Coxal fields I with 3 setae. Gnathosoma displaced on dorsal side ………………… N. ovata 7a Antero-median setae increase in length from the anterior to the posterior part of setal cluster. Setae a' and a'' of tarsi I slightly serrate. Setae v'TrI-IV serrate. Setae 3a smooth ………………………… ……….……………………………. N. levissima 7b Antero-median setae subequal in length. Setae a' and a'' of tarsi I smooth. Setae v'TrI-IV with barely discernible serration. Setae 3a serrate ………………………………………. N. ligare Ethical approval All applicable institutional, national and international guidelines for the care and use of animals were followed. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.