Life Stages and Phylogenetic Position of the New Scale-Mite of the Genus Neopterygosoma (Acariformes: Pterygosomatidae) from Robert’s Tree Iguana †

SIMPLE SUMMARY: This research presents a description of a new ectoparasitic scale-mite species, Neopterygosoma robertmertensi sp. n., collected from a Robert’s tree iguana (Liolaemus robertmertensi) from Argentina. For the first time, the description of females was accompanied by the description of the male and juvenile stages. The morphology of all post-embryonic stages of this species was analyzed in detail using scanning electron microscopy. Additionally, we conducted a phylogenetic analysis to determine its position within the genus and created an updated identification key for all Neopterygosoma species. The findings show that N. robertmertensi sp. n. is a part of the chilensis group and is a sister taxon to all Neopterygosoma spp. collected from Liolaemus pictus and L. chiliensis. ABSTRACT: A new pterygosomatid mite species, Neopterygosoma robertmertensi sp. n. (Acariformes: Pterygosomatidae) was collected from two specimens of Liolaemus robertmertensi (Liolaemidae) from Argentina. This new species is described based on active stages: adults (female and male) and juveniles (deutonymphs, protonymphs, and larvae) and quiescent stages (nymphchrysalis, deutochrysalis and imagochrysalis). The changes in morphological characters that occur during the ontogeny of N. robertmertensi have been analyzed in detail. A difference in larval sex morphology was observed for the first time in the family Pterygosomatidae (female larvae differ from male larvae in terms of the shape and size of the idiosoma and the position of the genital area). This new mite species is most similar to N. cyanogasteri but can be distinguished by the presence of different leg chaetotaxy patterns of genua IV and femora IV, four to six genital setae, three to five dorsomedial setae, and two to three ventromedial setae. Phylogenetic analysis was conducted based on 120 morphological characters of all Neopterygosoma spp. and four outgroup species using the maximum parsimony approach. The results indicated that this species is nested within mites of the chilensis group of Neopterygosoma associated with host species of the section chiliensis of Liolaemus s. str. An updated diagnosis of the chilensis group of Neopterygosoma and an identification key for all species of this genus has been provided.