The feather mites of the hoatzin Opisthocomus hoazin (Müller) (Aves: Opisthocomiformes), with the description of two new genera and six new species (Acari: Analgoidea, Pterolichoidea) Author Hernandes, Fabio A. Author Mironov, Sergey V. text Zootaxa 2015 4034 3 401 444 journal article 10.11646/zootaxa.4034.3.1 7c591ebc-507e-4ed0-9bfb-68c75dca4c30 1175-5326 242334 28877701-85F6-47B6-88DF-178E04AB16A6 Genus Hoazinacarus gen. nov. Type species: Hoazinacarus anisosetus sp. nov. Diagnosis. BOTH SEXES. Small-sized pterolichines. Idiosoma roughly ovate, egg-shaped, about 1.5 times longer than greatest width. Gnathosoma almost rectangular, slightly enlarged posteriorly. Prodorsal shield occupying mesal part of prodorsum and well developed posterior to scapular setae se, si . Two vertical setae vi present, long filiform, with bases close to each other. Scapular shields not developed dorsally. Humeral shields well developed, encompassing bases of setae c2, c3 and cp. Hysterosoma with extensive hysteronotal shield. Lateral sclerotized bands of hysterosoma absent. Scapular setae si well developed, thick stake-shaped with numerous additional spines in apical half, situated close to bases of corresponding setae se ; both pairs distant from body midline. Setae c2 thick spiculiform with numerous spicules; setae c3 thin spiculiform with smooth surface; humeral setae cp short filiform, much shorter than idiosoma width. Full set of hysteronotal setae occurring in pterolichids present. Cupules ia and im indistinct; hysteronotal gland openings gl well developed, situated posterior to setae e2 . Epimerites I fused into a Y. Bases of epimerites I, II simple, bases not modified, without inflations and connecting bridges. Legs I, II subequal. Tarsi I–IV without apicodorsal spines. Tarsi I, II without ventral extensions, subequal in length to corresponding tibiae. Tibiae, genua and femora of legs I–IV simple, without processes and extensions. Solenidia ω1 approximately at midlevel of tarsi I, II; setae ba near bases of corresponding solenidia ω1 . Solenidion σ2 of genu I absent, solenidion σ1 of genu I situated in basal part of segment. Condylophores normal (not strongly thickened in basal half). Ambulacral discs with smooth distal margin, with small apical extension on tarsi I, II. MALE. Opisthosomal lobes not expressed, opisthosoma widely rounded. Setae c2 d2, e2 thick stake-shape, with numerous additional denticles or spicules; setae f2 and ps1 short, with few branching spines; setae ps2 spiculiform; setae h1 minute filiform. Setae e1 short filiform, situated posterior to level of setae e2 and hysteronotal gland opening gl . Coxal fields I–IV open, without extensive sclerotized areas. Bases of trochanters I, II not flanked by narrow sclerotized bands connecting bases of epimerites. Genital apparatus between levels of trochanters III and IV. Genital papillae situated at level of genital arch apex. Paragenital apodemes absent. Adanal apodemes and shields absent. Anal discs present, circular; corolla smooth. Cupules ih absent. Legs III and IV subequal, not hypertrophied. Tarsus IV elongated, similar in form and size to tarsus III; modified setae d, e reduced to small alveoles. FEMALE. Hysteronotal shield split by narrow transverse band into two approximately equal pieces, covering almost entire dorsal surface of hysterosoma. Setae d2 large stake-shaped with numerous small spines; e2, f2, h1 short filiform; setae ps1, ps2 thin spiculiform, with numerous branching spines. Supranal concavity present, ovate. Oviporus situated at level of sejugal furrow. Epigynum present, semicircular, close to posterior tips of epimerites I and II. Copulatory opening terminal. Differential diagnosis. The new genus Hoazinacarus gen. n. has an unmistakable appearance within the family Pterolichidae and can be readily identified by the structure of scapular setae si , which in both sexes are stake-like with numerous spines branching out, and setae d2, e 2 in males and setae d 2 in females having the same structure. Within the family, this genus can be compared only with the genus Stakyonemus , having the same structure of scapular setae si and most lateral setae of the hysterosoma ( Figs. 21 A, 22A). Remarks. When mites were observed in ethanol before mounting in slides, the two pieces of the hysteronotal shield were often observed as articulated like a hinge, sometimes with an angle near 90 degrees. Observation of the live material is needed to clarify whether these mites actually can fold their dorsal shields and body in such a manner.