Ophidiotrichus 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

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 1953b, Bernini 1975) in having the following combination of character states. Integument pitted. Octotaxic system developed as 4 pairs of porose areas ( Fig. 10 ). Notogaster with 10 pairs of short setae; l and h series setae positioned lateral to porose areas ( Fig. 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 ). 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. 8B ). 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. 8B , arrow), visible by transparency in lateral mounts (see Fig. 3 D of Behan- Pelletier 2011). Indentation visible by transparency in ventral mounts ( Figs. 11 , 12A, C ). 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. 8B ); 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 c1. 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 c1, c3 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 (1953a) 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 (1953a) 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 (1953a) 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 (1953a). 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.

Figures

FIGURE 3. Ferolocella tessalata (Berlese), adult female, dorsal aspect, legs not illustrated, with arrow to squared base of interlamellar pocket. Scale bar = 50 µm.

FIGURE 10. Ophidiotrichus exastus Higgins, adult female, dorsal aspect, legs and rostral setae not illustrated. Scale bar = 50 µm.

FIGURE 11. Ophidiotrichus exastus Higgins, adult female, ventral aspect, legs and rostral setae not illustrated, with arrow to the tache pectorale. Scale bar = 50 µm.

FIGURE 8 A, B. Lateral aspect of podosoma of adult female, legs and notogaster removed: A, Joelia appalachia sp. nov., with arrow to lateral indentation on bothridium. B, Ophidiotrichus exastus Higgins, with arrow to ventral indentation in area of connection of pedotectum I to body wall. Scale bars = 50 µm.

FIGURE 12 A – D. Ophidiotrichus exastus Higgins, differential interference contrast microscope images of adults: A, ventral region anterior to middle of genital plate, with arrow to tache pectorale; B, detail of lateral of coxisternum in region of pedotectum II (PdII), with arrow to dens at tip of pteromorph folded over coxisternum; custodium and seta 4 c visible beneath; C, detail of tache pectoral e; D, detail of striae on anterior and lateral of coxisternum, tache pectoral e indicated with arrow. Scale bars: A – D = 25 µm.