Ophidiotrichus Grandjean, 1953, Grandjean, 1953

Behan-Pelletier, Valerie M., 2013, Adoribatella, Ferolocella, Joelia and Ophidiotrichus (Acari, Oribatida, Oribatellidae) of North America, Zootaxa 3637 (3), pp. 254-284: 271-272

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Ophidiotrichus Grandjean, 1953


Ophidiotrichus Grandjean, 1953  

Type species: Oribata tecta Michael, 1884   , p. 251

Combinations/Synonymy: Oribata tecta Michael, 1884   , Luxton 1989, p. 88 Notaspis connexus   var. borussicus Sellnick, 1908   , p. 31; Evans 1954, p. 809 Oribates connexus Berlese, 1904   , Luxton 1989, p. 88; Subías 2004, p. 170; Weigmann 2006, p. 361.

Diagnosis. Adult. Species comprising this genus are unique among Oribatellidae   (Grandjean 1953 b, Bernini 1975) in having the following combination of character states. Integument pitted. Octotaxic system developed as 4 pairs of porose areas ( Fig. 10 View FIGURE 10 ). Notogaster with 10 pairs of short setae; l and h series setae positioned lateral to porose areas ( Fig. 10 View FIGURE 10 ). Lamellae long, broad, with large cusps, medially fused for proximal third to three-quarters of length; cusps usually with small medial and lateral dentes. Interlamellar seta short to four-fifths length of lamella, setiform. Lamellar seta short, thick, heavily barbed ( Fig. 10 View FIGURE 10 ). Bothridial wall flask-shaped, with indentation laterally. Dorsophragmata paired. Genal tooth broad, subrectangular in shape, with longitudinal ridge laterally, with or without dens ventrodistally ( Fig. 8 B View FIGURE 8 A, B ). Tutorium narrow, lamelliform, lying parallel to dorsal contour of prodorsum in lateral aspect, extending or not anterior to insertion of rostral seta;cusp narrowly triangular and tapering to point, or narrowly rectangular, with 3–4 dentes distally. Pedotectum I with distinct, deep concave indentation in ventral wall ( Fig. 8 B View FIGURE 8 A, B , arrow), visible by transparency in lateral mounts (see Fig. 3 View FIGURE 3 D of Behan- Pelletier 2011). Indentation visible by transparency in ventral mounts ( Figs. 11 View FIGURE 11 , 12A, C View FIGURE 12 A – D ). Epimeral setal formula 3 - 1-3 - 2 or 3 - 1-3 - 3. Custodium present, with short, free distal point. Axillary saccule present at base of palp. Chelicera chelate-dentate, large relative to size of body. Palp setal formula 0–2 – 1–3 – 9 (1); eupathidium acm subequal in length to solenidion, forming double horn with solenidion along length. Seta m of gena subequal in size and shape to seta a. Humerosejugal porose organ Ah expressed as porose area ( Fig. 8 B View FIGURE 8 A, B ); porose area Al present or absent, when present expressed as porose area. Legs monodactylous. Femur III with seta l’ present (where setation has been studied); seta v' of genua I and II present. Setae l” of genua I and II and tibia II thicker, more heavily barbed and shorter than other setae on these segments. Without anterodorsal spines close to, or between, solenidia φ 1 and φ 2 on tibia I.

Immatures. Apopheredermous, with scalps of preceding instar maintained away from dorsal integument by modified setae da and dorsally directed setae dp and c 1. Setae da serpentine in shape with flattened tip. Only setae da and dm found beneath scalp, seta dp positioned outside scalp and more laterally than in other nymphal Oribatida   , including known nymphal Oribatella   . Body colorless, cuticle without plicae or sclerites. All or most gastronotic setae long; setation usually unideficient: larva with 11 or 12 pairs, protonymph deutonymph and tritonymph with 15 pairs (adult loses c 1, c 3 and d series). 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. 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. Grandjean (1953 a) proposed Ophidiotrichus   as a replacement name for Tectoribates   auct. (= of some authors). Tectoribates Berlese 1910   , with Sphaerozetes (Tectoribates) proximus Berlese 1910   as type species, was and is valid, but the original description was poor and the type species could not be found at the time of Grandjean’s study. Grandjean (1953 a) noted that several authors, beginning with Sellnick (1928), wrongly considered Oribata tecta Michael   as the type species of Tectoribates   . However, as Grandjean pointed out, O. tecta Michael   is not similar to S. (T.) proximus   , and though both concepts of Tectoribates   were maintained in the literature, only Tectoribates Berlese   , with Sphaerozetes (Tectoribates) proximus Berlese   as type species, is valid. Fortuitously, the type species, Sphaerozetes (Tectoribates) proximus Berlese   , was subsequently rediscovered and thoroughly redescribed by Bernini (1973). Tectoribates   is the subject of ongoing research as there are undescribed species in North America (Behan-Pelletier & Walter, in prep.).

Grandjean (1953 a) proposed Oribates connexus Berlese, 1904   as type species of Ophidiotrichus   , primarily because he had representatives of all stages of this species. His redescription of O. connexus   focused on immatures, which he illustrated in his usual incomparable manner. Besides O. connexus   , there are a number of species of Ophidiotrichus   described: O. tectus (Michael, 1884)   from England, O. vindobonensis Piffl, 1961   from Austria, described as a subspecies of connexus   , but considered a valid species by Weigmann (2006); O. exastus Higgins, 1965   from eastern USA (redescribed below), O. ussuricus Krivolutsky, 1971   from the Russian Far East, O. oglasae Bernini, 1975   from Italy, O. corsicanus Bernini & Avanzati, 1983   from Corsica, and O. borussicus (Sellnick 1908)   . The latter was originally considered a variety of connexus   , but it was subsequently compared with type material of O. tectus   by Evans (1954, p. 809), who considered it a synonym of O. tectus   . But disagreement on the synonymy of O. connexus (Berlese 1904)   with O. tectus (Michael)   continued. As Luxton (1989) noted, inaccuracies in Michael’s illustration of O. tectus   (illustrated as tridactylous, but the type material is monodactylous) were noted by Grandjean (1932, p. 304) and Evans (1954, p. 809), but were not noted by Grandjean (1953 a). Luxton (1989) redescribed O. tecta   based on Michael’s material at the British Museum of Natural History and designated a lectotype. Luxton (1989) did not specifically note the synonymy of O. connexus   and O. tectus   , but Krivolutsky (1975) established the synonymy of O. connexus var. borussicus   with O. tectus   . This synonymy was recognised by Subías (2004, p. 170) and Weigmann (2006, p. 361); after having examined a specimen of O. tectus   from Ireland I also concur.