Oribatellidae Jacot, 1925

Ermilov, Sergey G. & Behan-Pelletier, Valerie M., 2014, Revision of Fenestrobates (Acari, Oribatellidae) with description of F. marauni sp. nov., from South America, and new diagnosis for Oribatellidae, Zootaxa 3827 (2), pp. 258-272 : 268-270

Oribatellidae Jacot, 1925

Diagnosis. Adult. Poronotic Brachypylina with the following character states. Prodorsum. Lamellae long, broad, with large cusps, medially converging, diverging or contiguous; cusps with or without medial and lateral dentes; translamella variable in width and depth, with or without medial tooth, or translamella absent. Bothridium flaskshaped with indentation laterally. Notogaster. Immovable pteromorphs with small dens anteroventrally. Notogaster anteriorly flattened to convex, with or without ridges lateral of bothridium. Lenticulus present or absent. Pair of cavities on notogaster present or absent. Octotaxic system as four pairs of porose areas or saccules; usually without sexual dimorphism, when present that of male modified, and number of porose areas reduced. Notogaster with 10 to 14 pairs of short to very long setae. Lateral podosomal and epimeral regions. Genal tooth subtriangular to subrectangular in shape, with or without dens ventrodistally, with or without ridge ventrally. Tutorium lamelliform, narrow to wide, cusp rectangular or subrectangular, with dentes distally, lying parallel to dorsal contour of prodorsum in lateral aspect, extending or not anterior to insertion of rostral seta, or cusp of tutorium absent. Humerosejugal porose organ Ah discrete, expressed as porose area or saccule; Am diffuse porose area; Al when present expressed as porose area or saccule. Custodium usually present, with short to long, free distal point. Epimeral setal formula 3–1–3–3 or 2(3)–1–3–2 or 3–1–3–2 or 2–1–3–2 or 3–1–2–2; seta 4c present or absent. Setae 3b, 3c and sometimes 4b ( Fenestrobates capucinus ), and 4c (most species of Oribatella ) thick, spinous, very long. Pedotectum I large. Ventral depression between pedotectum I and the lateral body wall varying from small Ushaped depression to large flask-shaped pit depending on genus. Pedotectum II with or without blunt tooth posterolaterally or paraxially. Gnathosoma . Axillary saccule present at base of palp. Subcapitulum diarthric. Chelicera chelate-dentate, with 2 cheliceral setae; (chelicera elongated in one species of Oribatella and Joelia ). Mentum with or without tectum, with or without recurved ridge distally. Palp setal formula 0–2–1–3–9(+ω) or 0–2–1–3–8(+ω); eupathidium acm subequal in length to solenidion, forming double horn with solenidion along length or distally (in Oribatella quadridentata Banks 1895 solenidion almost 2.5 × length of acm). Anogenital region. Six pairs of genital setae. Aggenital seta present or absent. Two pairs anal setae; three pairs adanal setae. Postanal porose area present (data for Siciliotrichus Bernini, 1983 unknown). Legs monodactylous, heterobidactylous or heterotridactylous. Trochanter III with seta l’ present or absent; femur III with seta l’ present or absent; seta v' of genua I and II present or absent. Genua I and II with or without small cusp ventrodistally. Setae l” of genua and tibiae I and II thicker, more heavily barbed and longer than setae l’ on these segments. One or two anterodorsal spines present or not on tibia I close to, or between, solenidia φ 1 and φ 2.

Immature. Apopheredermous, with scalps of preceding instar maintained away from dorsal integument by modified setae da and dorsally directed h 1 ( Oribatella ), or modified setae da and dorsally directed setae dp and c 1 ( Ophidiotrichus ). Setae da usually showing modification for attachment of scalp of preceding instar, may be serpentine in shape with flattened tip ( Ophidiotrichus ). Axillary saccule present, where investigated. Body usually colorless, cuticle without plicae; hysterosomal sclerites present or absent. Gastronotal setation usually unideficient; larva with 11 or 12 pairs, protonymph with 14 or 15 pairs, deutonymph and tritonymph with 13 or 15 pairs. Setae dm and dp subequal in length to da in all immatures, or much shorter than da in deutonymph and tritonymph, or dm and dp (one species), or c 1 and dm (one species) absent from deutonymph and tritonymph. Pair of humeral organs present laterally in sejugal region. Without apodemato-acetabular tracheal system or porose homologues. Paraprocts atrichous in larva, protonymph and deutonymph. Genital setal formula (larva to adult): 0–1–3–5–6. Aggenital setal formula 0–0–1–1–1, or aggenital seta absent. Opisthonotal gland present in all instars. Cupule development normal. Bothridium and bothridial seta fully formed in all instars. Setation of protonymphal leg IV normal (0–0–0–0–7). Larva to deutonymph with circular line of dehiscence, such that dorsal scalp separates from ventral piece at ecdysis.

Remarks. The adult diagnosis given is based on that of Grandjean (1953 b), the extensive research of Bernini (1975, 1978, 1983) publications by Shtanchaeva & Subías (2009), Behan-Pelletier (2011, 2013), Behan-Pelletier & Walter (2012), Ermilov & Anichkin (2012) and Seniczak & Seniczak (2013).

The immature diagnosis is mainly based on immatures of Oribatella and Ophidiotrichus . Immatures of Ophidiotrichus tectus ( Michael, 1884) were described by Grandjean (1953b). Immatures of Fenestrobates and other oribatellid genera, Fberninia , Ferolocella , Siciliotrichus are unknown, but the presumed deutonymph of Joelia fiorii ( Coggi, 1898) was described by Grandjean (1956 b). The seminal paper by Grandjean (1953 a) on immatures of O. calcarata (C.L. Koch, 1835) is the framework for any evaluation of oribatellid immatures, which, as Behan-Pelletier and Walter (2012) noted, continue to surprise in their variation. For example, Seniczak and Seniczak (2013) describe immatures of Oribatella calcarata that do not bear scalps. Furthermore, some nymphs they examined lacked notogastral setae c 1 and dm.

Ignorance of immatures of most oribatellid genera undoubtedly contributes to disagreement in the literature as to the number of genera that should be included in Oribatellidae , for example, Schatz et al. (2011; 10 genera) and Subías (2014; 8 genera). Subías (2014) included Cuspidozetes Hammer, 1962 , Ferolocella Grabowski, 1971 , Joelia Oudemans, 1906 , Novoribatella Engelbrecht, 1986 , Ophidiotrichus Grandjean, 1953 , Oribatella , Prionoribatella Aoki, 1975 and Siciliotrichus Bernini, 1983 . Fberninia Özdikmen, 2008 and Fenestrobates are considered subgenera of Oribatella by Subías (2014), though we treat them as genera, herein. Overall we follow Subías’ (2014) concepts with the following reservations.

We consider Cuspidozetes a member of Ceratozetidae . Hammer (1962) noted that femora I and II of the type species, C. armatus Hammer, 1962 , are similar to those of Melanozetes and Fuscozetes . Furthermore, her illustration of tibia and tarsus I of this species shows a setiform seta l”, whereas this seta is spinous in all genera of Oribatellidae .

Aoki (1975) described Prionoribatella as being similar to Oribatella but with: the lamellar cusp having a small inner tooth and a large and broad outer tooth; lamellar seta inserted closer to the inner tooth; legs monodactylous; and the rostrum pointed, without incisions. These characters states have been found in other species of Oribatella ( Behan-Pelletier 2011, Shtanchaeva & Subías 2009), and we consider Prionoribatella a subgenus of Oribatella .

Engelbrecht (1986) proposed Novoribatella with Tectoribates transcriptus Mahunka, 1985 as type species, and described three additional species, all well illustrated. None shows the ventral depression between pedotectum I and the lateral body wall, the character state that is a distinct apomorphy for Oribatellidae . Species of Novoribatella have a morphology closely related to that of Tectoribates , recently revised for North America by Behan-Pelletier and Walter (2013). It is possible that Novoribatella is also a member of the Tegoribatidae , as has been proposed by the latter authors for Tectoribates .