Fagacarus Fain et Norton, 1979

KlimovK, Pavel B., Kolesnikov K, Vasiliy B., KhaustovK, Alexander A. & OConnor K, Barry M., 2024, A new mite species Fagacarus absalom sp. n. (Astigmata: Acaridae) from the Eastern Palearctic, with 18 rRNA molecular barcodes, Acarologia 64 (2), pp. 542-553 : 543-544

Genus Fagacarus Fain et Norton, 1979

Type species: Fagacarus verrucosus Fain et Norton, 1979 , by original designation.

Diagnosis — Adults. Chelicera with one setae; subcapitulum with paired hemispherical filter apparatus at sides of oral opening well developed, with oblique rows of spines. Grandjean’s organ reduced; dorsal setae long, rounded in cross-section, heavily barbed; setae ve, f 2 and c 3 absent, other idiosomal vi (, se, si, c 1, c 2, c p, d 1, e 1, d 2, e 2, h 1, h 2, h 3) setae present. Cuticle dorsally and in part ventrally with numerous raised protuberances forming a reticulate pattern. Tarsal setae ba I-II spiniform, situated near ω 1 ; setae ~~ aa absent. Genua I with two solenidia. Genual setae nG III absent. Female. copulatory opening separated from anus by distance greater than half of anus length. Male. genital apparatus located between tarsi IV, with widened posterior part. Anal suckers vestigial, ad 1 and ad 2 minute or reduced to alveoli; ps 3 situated at anterior level of anus. Tarsus IV with a dorsal crista.

Heteromorphic deutonymph. Gnathosoma with one pair basal setae on dorsal sides, palpal remnants without setae. Setae ve absent. Setae si, c 1, d 1, e 1 and h 1 longer than other dorsal setae. Setae 1a, 3a, 4a conoidal. Coxal fields II and III closed. Sternum long, free. Ventrum present. Attachment organ with conoidal setae ps 2 situated at posterior level of central suckers ad 1 +2, posterior to midline of ad 1+2 and anterior to ps 1. Bases of conoidal setae ps 1 and ps 2 with long subcuticular sclerites, distinctly extending beyond the posterior level of attachment organ. On tarsus I, solenidion ω 3 situated in common field with solenidion 1 ω ; setae ba I and aa absent. Tarsal seta e I with very large, triangle-shaped tip; e II needle-like, shorter than claw; e III-IV spiniform. Tarsal setae p, q III and IV with attenuate tips. On genu III, setae nG III and solenidion σ III absent.

Remarks — The genus Fagacarus is similar to the genus Schwiebea sharing the following character states. Adults: Grandjean’s organ is reduced; setae ve, c 3 and f 2 are absent; tarsal setae r IV, gT I-II and hT I-II are spiniform; tarsal setae aa are absent; tarsal setae ba I-II spiniform, situated at base of tarsus, adjacent to ω 1 ; tarsal setae e I-II are spiniform, massive. Female: adanal setae ad are absent; tarsal setae la I-II are spiniform; tarsal setae ra and la

I-II are subterminal. Male: the genital apparatus is posterior to anterior apodemes IV and close to the anus; tarsal setae f I-II are simple; solenidion φ IV is spiniform. Heteromorphic deutonymph: setae ve are absent; tarsal setae aa absent; solenidion σ III is absent.

The genus Fagacarus differs from Schwiebea by the following character states. Adults:

the subcapitulum has paired, hemispherical structures representing a filter apparatus (absent in Schwiebea ); the dorsal setae are heavily barbed (smooth or very finely barbed in Schwiebea koerneri ); the dorsal body is covered with raised, sclerotized protuberances (smooth in most Schwiebea , pitted in S. koerneri , or with small network of protuberances in nymphal stages of S. koerneri ). Male: the opisthosomal shield is absent (present in Schwiebea ); the anal suckers are vestigial (well developed in Schwiebea ); adanal seate ad 1 and ad 2 are minute or alveolar (ad 1 and ad 2 or their alveoli absent in Schwiebea ). Heteromorphic deutonymph: dorsal setae si, c 1, d 1, e 1 and h 1 are longer that other dorsal setae (subequal in Schwiebea ); palps of gnathosoma without setae (with a pair of setae in Schwiebea ); tarsal setae e I with a very large, triangle-shaped tips (setae e I rounded, not triangle-shaped Schwiebea in).