Stibarokris annae n. sp. from Ciconia maguari (Gmelin) (Ciconiiformes: Ciconiidae), a new species of quill mites (Acariformes: Syringophilidae) exhibiting dimorphism of females.

A new quill mite species having dimorphic females Stibarokris annae n. sp. (Acariformes: Syringophilidae) is described from the maguari stork Ciconia maguari (Gmelin) (Ciconiiformes: Ciconiidae) from Uruguay. "S-form" females of S. annae differ from S. phoeniconaias Skoracki & OConnor, 2010 by the hysteronotal shield not reaching setal bases d1 (vs hysteronotal shield bearing setal bases d2 and d1 in S. phoeniconaias), the length ratio of setae ag1:ag2:ag3 1:1-1.4:2-2.4 (vs 1:1:1.2-1.3), the genital setae g1 2-2.5 times as long as g2 (vs g1 1.4-1.8× as long as g2), the fan-like setae of legs III-IV with 15-17 tines (vs with 6-8 tines) and the length of setae f2 (230-255 vs 295-370 µm), h1 (25-30 vs 45-55 µm), ag1 (125-165 vs 245-285 µm) and ag2 (145-180 vs 245-270 µm). "C-form" females of S. annae are distinguishable from S. phoeniconaias ("C-form") by the longitudinal branch of the peritremes with 14-16 chambers (vs 12-13 chambers in S. phoeniconaias), the propodonotal shield weakly sclerotised and punctate along its lateral borders (vs well sclerotised and apunctate), the hysteronotal shield represented by an oval area covered by delicate striations (vs distinct hysteronotal shield), genital setae g1 1.5-1.8 times as long as g2 (vs g1 and g2 subequal in length), the fan-like setae p' and p" with 10 tines (vs with 5 tines) and the length of setae ve (120-130 vs 185-195 µm), si (120-130 vs 220 µm), se (180-200 vs 245-295 µm), c1 (180-195 vs 270-285 µm), d2 (180-205 vs 265-270 µm), d1 (195-205 vs 255-285 µm) and e2 (195-215 vs 285-320 µm).