Fenestrobates Balogh and Mahunka 1969

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 : 259-260

Fenestrobates Balogh and Mahunka 1969

Type species: Fenestrobates capucinus Balogh and Mahunka, 1969, p.62

Oribatella (Fenestrobates) capucinus ( Balogh and Mahunka, 1969) Subías, 2004, p. 172 .

Diagnosis. Adult. Species comprising this genus are unique among Oribatellidae ( Grandjean 1953 b, Bernini 1978) in having the following combination of character states. Integument micropunctate/microfoveolate. Lamella and pedotectum I with fine, long longitudinal striae. Rostrum medially with longitudinal ridge; rostral tectum with small u-shaped indentation medially. Notogaster flat to slightly convex anteriorly. Pteromorph with small dens ventrodistally; without ridges anteriorly on notogaster lateral of bothridium. Lenticulus absent. Octotaxic system as four pairs of porose areas. Notogaster with 10 pairs of short to long setae. Lamellae long, broad, with large, medially converging cusps; cusps with large medial and lateral dentes; translamella very short or absent; interlamellar pocket present or absent. Interlamellar setae positioned medially or laterally on posterior of lamella. Bothridium flask-shaped with indentation laterally. Genal tooth broad, subtriangular in shape, with dens ventrodistally, without longitudinal ridge ventrally. Tutorium curved, lamelliform; cusp rectangular or subrectangular, with teeth distally and dorsodistally, lying parallel to dorsal contour of prodorsum in lateral aspect, extending well anterior to insertion of rostral seta. Epimeral setal formula 2(3)–1–3–2, 2 or 3 pairs of setae on epimere I; seta 4c absent. Setae 3b, 3c and 4b, or 3b and 3c only, thick, barbed, very long. Ventral depression between pedotectum I and the lateral body wall distinctly flask-shaped, extending into podosoma ( Figs. 2 , 16 ), such that in lateral aspect invagination extending well ventral of level of pedotectum II. Pedotectum II with or without blunt tooth posterolaterally. Custodium present, with short free distal point. Chelicera chelate-dentate. Mentum with narrow tectum, overlaying insertion of seta m, without recurved ridge distally. Palp setal formula 0–2–1–3–9(+ω); eupathidium acm subequal in length to solenidion, forming double horn with solenidion along length. Axillary saccule present at base of palp. Humerosejugal porose organ Ah expressed as concave porose area, with distinct margin; Am diffuse porose area; Al porose. Six pairs of genital setae. Aggenital seta and its alveolus absent. Anal setae well spaced or together on anterior half of plate. Postanal porose area present. Legs monodactylous. Trochanter III with one seta; femur III with seta l’ present; seta v' of genua I and II present. Setae l” of genua I and II thicker, more heavily barbed and longer than setae l’ on these segments. Trochanter and femur IV each with ventral carina, that of femur IV with dens ventrodistally. One or two anterodorsal spines present on tibia I close to, or between, solenidia φ 1 and φ 2.

Immatures. Unknown.

Reproductive Mode. Based on data from the type series of F. marauni sp. nov., species of Fenestrobates are bisexual.

Remarks. 1. The name Fenestrobates refers to the “fenestrate tectum” with “the large rounded foramina” that Balogh and Mahunka (1969) considered covered the epimeral region. This was a misinterpretation of the ventral depression between pedotectum I and the lateral body wall which is unusally developed in Fenestrobates . This distinct concave depression or indentation (pdp) is found in all genera of Oribatellidae . Grandjean (1956 a) illustrated this indentation for Joelia fiorii ( Coggi, 1898) and then ( Grandjean 1956 b) discussed it extensively, noting its position ventrally between pedotectum I and the lateral body wall. In Ophidiotrichus Grandjean, 1953 , Joelia Oudemans, 1906 and Fenestrobates this depression can be seen to various extent with transmitted light in ventral mounts as a thickened, circular region. Grandjean (1956 b, his Figs B, C) gave the term ‘ tache pectorale ’ (Pe) for this region. In Fenestrobates this concave depression is very large and flask-shaped, extending ventral of the level of pedotectum II, almost reaching ventrally to the coxisternum, and giving appearance of foramen when viewed in transmitted light ventrally (compare pdp in Figs 2 and 3 and Figs 16 and 19 ). As Grandjean (1956 b) noted this depression does not conform to the shape of the femur or to leg setae. The position of this depression may be related to the opening of trachea I in the acetabulum of leg I, and it may function as part of a plastron system in a manner similar to those of other oribatid taxa, e.g., some Ameroidea ( Chen et al. 2004). This depression is unknown outside Oribatellidae . It is absent from species of Adoribatella Woolley, 1967 , previously considered a member of Oribatellidae (Behan-Pelletier 2013) . Its absence in species of Tectoribates Berlese, 1910 is one of the arguments given for removal of that genus from Oribatellidae ( Behan-Pelletier & Walter 2013) .

2. Adults of all Oribatellidae , including Fenestrobates , have lamellae with large cusps. The type species, Fenestrobates capucinus has a small interlamellar pocket as is found in many species of Oribatella , but absent from others; it is very small, easily overlooked, and was not illustrated by Balogh and Mahunka (1969).

3. Adults of oribatellid genera have a flask-shaped bothridium with an indentation laterally, as has Fenestrobates . This has been described clearly for Oribatella berlesei ( Michael, 1898) ( Bernini 1977, Plate I, Fig. 3 ), Fberninia helenae ( Bernini, 1975) ( Bernini 1975, Plate XIII, 1), Siciliotrichus siculus Bernini, 1983 ( Bernini 1983, Fig. 2b ), Joelia fiorii ( Grandjean 1956 a, Fig. 2A ), and Ophidiotrichus exastus Higgins, 1965 (Behan- Pelletier 2013).

4. The humerosejugal porose organ Ah is usually developed as a discrete porose area in oribatellid species, including species of Fenestrobates , though it is a saccule in Oribatella quadridentata Banks, 1895 . Similarly Al is developed in all oribatellids examined for this porose area, other than O. quadridentata ( Behan-Pelletier 2011) , and is found in Fenestrobates .

5. A striking feature of Fenestrobates species is the long spinous form of epimeral setae 3b and 3c. In F. capucinus , seta 4b also is spinous. Such development of these setae is rare in Oribatella but is found in O. rossicus , redescribed below. In contrast, a long spinous seta 4c is found in Fberninia , Ferolocella and many species of Oribatella . This character is variable in other families of poronotic Brachypylina , e.g., in the chamobatid genus Xiphobates Pavlichenko, 1993 , epimeral setae 4b and 4c can be spinose, but not setae of epimere III.

6. The postanal porose area is expressed in all Oribatellidae , including Fenestrobates . This character also is expressed in all known Tegoribatidae and most representatives of Ceratozetoidea and Galumnoidea.

7. The sharp dens anteroventrally on the pteromorph in Fenestrobates ( Fig. 3 ) is a character state expressed to some extent in all Oribatellidae . In species of Joelia there is no distinct dens, rather the pteromorph is pointed anterventrally, similar to that in the ceratozetoid Lamellobates reticulatus Behan-Pelletier, 1998 . Such a dens is not found in other Ceratozetoidea (species in Ceratozetidae , Punctoribatidae , Zetomimidae examined), in Tegoribatidae ( Hypozetes , Tegoribates , Tectoribates examined), or in Achipteriidae ( Achipteria , Parachipteria and Dentachipteria examined).

8. An anterodorsal spine between solenidia φ 1 and φ 2 on tibia I was incorrectly considered an apomorphy of oribatellid genera by Behan-Pelletier (2013). This character state is present in species of the tegoribatid genus Tectoribates , and is absent from the oribatellid genus Ophidiotrichus (its presence in Siciliotrichus is unknown).

9. Two other species, both from Russia, have been ascribed to this genus: Fenestrobates rossicus Krivolutsky, 1974 and F. vicinus Ryabinin 1975 . These are redescribed below and considered members of Oribatella sensu stricto. Therefore, Fenestrobates is only known from South America.

Figures

FIGURES 1–3. Fenestrobates marauni sp. nov., adult: 1—dorsal view; 2—ventral view (legs not illustrated); 3—lateral view. Scale bar 100 µm.

FIGURES 16–20. Fenestrobates marauni sp. nov. Differential interference contrast microscope images of adult, 16–18: 16—lateral, showing pedotecta I and II (Pd I, Pd II), flask shaped depression (pdp), humerosejugal porose area Ah (four layers combined); 17—lamellae and posterior of prodorsum, showing dorsophragmata; 18—detail of notogastral integument and porose area Aa. Fenestrobates capucinus Balogh and Mahunka. Differential interference contrast microscope images of adult, 19, 20: 19—coxisternum, showing flask shaped indentation of pedotectum I seen in ventral aspect (four layers combined); 20—rostrum, lateral orientation, showing medial ridge, tutorium (tu) (specimen with ventral teeth), genal tooth, (three layers combined).