Nanodectes Mironov, 2008

Mironov, Sergey V., Literak, Ivan & Čapek, Miroslav, 2008, New feather mites of the subfamily Pterodectinae (Acari: Astigmata: Proctophyllodidae) from passerines (Aves: Passeriformes) in Mato Grosso do Sul, Brazil, Zootaxa 1947, pp. 1-38 : 31-32

Genus Nanodectes Mironov gen. n.

Type species: Nanodectes formicivorae Mironov sp. n.

Both sexes. Moderately elongated pterodectines. Vertical setae ve absent. Hysterosomal setae d1, d2, e2, f2 absent. Prodorsal shield covering most part of prodorsum, with well developed posterior angles. Scapular shields narrow. Humeral shields present. Setae c2 situated dorso-laterally on humeral shields. Setae wa, la and ra approximate to each other and situated at midlevel of tarsi I, II. Seta gT of tibia I in proximal half of seg- ment. Setae cG and mG on genua I, II setiform. Solenidion σ 1 of genu I subequal to solenidion ω 3 on tarsus I. Femora I, II usually bear ventral crests, other segments of these legs without processes and other modifications. Seta sR of trochanters III present; solenidion σ 1 of genu III present. Supranal concavity present.

Male. Epimerites I fused into a narrow V, fused part not connected with epimerites II. Coxal fields II–IV open; epimerites II and IV without extensive sclerotized areas. Opisthosomal lobes roughly angular. Terminal cleft as a wide inverted V; narrow interlobar membrane present. Setae h3 long setiform, situated on lobar apices. Setae h1 situated anterior to bases of opisthosomal lobes. Setae ps1 setiform, minute. Genital arch reduced, represented by sclerotized ring at base of aedeagus, base of genital apparatus at level of trochanters IV; aedeagus sword-shaped. Genital papillae anterior to base of genital apparatus. Pregenital apodeme, paragenital apodemes, genital shield and other sclerotized structures around genital apparatus absent. Setae 4a situated on soft tegument of coxal fields IV. Opisthoventral shields present, narrow. Corolla of anal suckers with indentation. Adanal shields present, situated antero-lateral to anal suckers. Setae ps3 situated anteromesal to anal suckers, noticeably approximate to anal opening. Setae g and ps3 arranged in longitudinal rectangle or inverted narrow trapezium. Legs I slightly thicker than legs II. Legs III and IV subequal in size and form. Solenidia ϕ of legs III, IV subequal. Tarsus IV without apical claw-like process, setae d and e buttonlike.

Female. Epimerites I fused into a narrow V or U. Lobar region of opisthosoma clearly separated from remaining part of opisthosoma; opisthosomal lobes well developed, with long terminal appendages. Hysteronotal shield split dorsally into anterior and lobar shields. Macrosetae h2 with spindle-like basal part and filiform apical part. Epigynum horseshoe-shaped, large. Translobar apodemes present. Legs I slightly thicker and longer than legs II. Legs III, IV subequal in size. Solenidia ϕ of tibiae III much longer than on tibiae IV.

Hosts: Birds of the family Thamnophilidae (Passeriformes) .

The genus is monotypic.

Differential diagnosis. The genus Nanodectes easily differs from all known pterodectine genera by loss of four pairs of hysterosomal setae (d1, d2, e2, f2) in both sexes and reduction of genital arch in males. This odd pterodectine genus combines several features of the Pterodectes and Trochilodectes generic groups. On the one hand, in males of Nanodectes , setae ps3 are situated antero-mesal to the anal suckers and adjacent to the anal opening. This feature occurs in the Proterothrix complex ( Proterothrix, Neodectes Park et Atyeo, 1971 and Megalodectes Park et Atyeo, 1971 ) that is quite probably a plesiomorphic state of this character of the subfamily, because this position of setae ps3 is common for most representatives of the superfamily Analgoidea . On the other hand, in both sexes of Nanodectes , setae wa, ra, la are situated at the midlevel of on tarsi I, II, and solenidion σ 1 on genua I is subequal in length to solenidion ω 3 on tarsi I, which are diagnostic features of the Trochilodectes group.

Etymology. Contraction of nano (dwarf, pygmy in Greek) and Pterodectes , to point out the relatively small size of these pterodectines, masculine.