Praoppiella oanae MIKO et MOUREK, 2012

Miko, Ladislav, Mourek, Jan, Meleg, Ioana N. & Moldovan, Oana T., 2012, Oribatid Mite Fossils From Quaternary And Pre-Quaternary Sediments In Slovenian Caves I. Two New Genera And Two New Species Of The Family Oppiidae From The Early Pleistocene, Acta Musei Nationalis Pragae Series B 68 (1 - 2), pp. 23-34 : 28-30

Praoppiella oanae MIKO et MOUREK sp. nov.

D i a g n o s i s: Praoppiella with auricular interbothridial tubercles, relatively short, smooth and claviform sensillus and weakly developed axial notogastral tubercles. Rostrum rounded, pedotectum I well developed and postbothridial enantiophysis with both anterior and posterior tubercle present.

M e a s u r e m e n t s: Body of the single available individual (holotype) damaged and partly deformed, enabling only approximate measurements. Length of body 230 Μm, length of prodorsum 80 Μm. Maximum width of notogaster about 140 Μm, maximum width of prodorsum (between tips of pedotecta I) 80 Μm.

G e n e r a l c h a r a c t e r s: Body yellowish-reddish brown coloured. Surface densely covered by dirt and other artefacts, allowing neither detailed study of fine structures, nor observation and reliable identification of many setal insertions. Surface of lateral parts of prodorsum and podosoma with granulation, rugged or granulated surface also apparent on ventral plate.

P r o d o r s u m: ( Text-fig. 4A , Pls 3A, E). Triangular, with slightly elongated rostral part. Rostral margin broadly rounded, with particular form (Pl. 3F): anterior border rounded, forming more transparent band; at inner edge of band, where cuticle appears thicker and coloured, with jagged, dentate cuticular pattern, integrated within the rostral cuticle. Short and relatively straight lamellar costulae running anteromediad, reaching slightly beyond insertions of interlamellar setae, followed by indistinct line almost reaching insertions of lamellar setae ( Text-fig. 4A , Pl. 1A). Interbothridial tubercles distinct, large, auricular. Bothridia relatively very large, cup-like, positioned near anterior edge of notogaster, without postbothridial lobe or attached tubercle. However, a pair of tubercles (postbothridial enantiophyse, Text-fig. 4E ) present behind bothridia, loosely connected with bothridial base by thickened cuticle. Prodorsal setae lost from the studied individual, but a seta-like structure observed ( Text-fig. 4 A ) in location of right lamellar seta. Rostral setae inserted close to the jagged cuticular structure of rostrum, lamellar and interlamellar setae insert- ed at normal positions as in other Oppiellinae . Sensillus ( Text-fig. 4E , Pls 3D, E) relatively short, claviform (or clubshaped), about 37 Μm long. Head about the same length or slightly shorter than the stalk, with lighter part observable in some views in transmitted light ( Text-fig. 4E ), indicating most probably spoon-like invagination of surface from medial side (perhaps artefact). Second sensillus missing. Pedotecta I present, relatively well developed.

N o t o g a s t e r: ( Text-figs 4 C-D, Pl. 3B). Rounded, broadly oval. External (postbothridial, humeral) pair of tubercles on anterior margin more strongly developed, broad, rounded, U-shaped or triangular, blunt, with short but observable crista running posteriad. Central pair of tubercles weakly developed, present as a short, rounded or semicircular ridge just on the border of notogaster (Pl. 3C). Notogastral setae not preserved, insertions not easily identifiable. Insertions of 10 pairs of notogastral setae assumed ( Text-fig. 4 C ), pair c2 relatively far behind anterior margin of notogaster. Additional pores or insertion-like structures observed on notogaster, but unclear if should be assumed to be artefacts or real structures.

V e n t r a l p a r t: ( Text-fig. 4B ). Very difficult to observe in our individual. Discidium not prominent, broadly rounded. Genital and anal plates lost; size of apertures and mutual distance as usual in Oppiidae , anal aperture much larger than the genital one. Epimeral border 4 developed as quite distinct, broad transversal ridge, slightly bent forward anterior to genital opening. Insertions of epimeral setae hardly identifiable, only insertions of 4a, 4b and 4c more clearly visible, these being inserted in one row anteri- or to the epimeral border IV. Insertions 3a and perhaps also 1b found as indicated in Text-fig. 4 B . Adanal and aggenital setae inserted in usual positions.

L e g s: Lost from the single available specimen, only trochanters III and IV preserved but without setae (Pl. 3A, E), thus setal insertions impossible to identify.

M a t e r i a l e x a m i n e d: Single damaged individual (holotypus) found in clastic Pleistocene sediments of the Račiška cave in Classical Karst (Kras), Slovenia (sample R4 , same as R quadrituberculatus ) . The holotype mounted in Canada balsam is preserved in the acarological collection of the Senckenberg Museum in Goerlitz , Germany .

D e r i v a t i o n o m i n i s: The genus name refers to the similar recent genus Oppiella . Prefix Pra - in genus name is an equivalent to ”ancient“ in several Slavic languages, the species name is dedicated to colleague and coauthor Oana Moldovan from the Emil Racovita Institute of Speleology, Romania, who discovered the material and provided it for study.

R e m a r k s: The rostrum of this species has a quite peculiar structure. The denticulate pattern on the margin of the rostral cuticle resembles the rostral teeth of recent Suctobelbella species. Presence of a much weaker, thin, transparent external band, forming a complete, rounded rostral tectum, may represent either an ancient or derived state of rostrum development. As the cuticle of this specimen is generally heavily damaged, the possibility that the structure is an artefact also cannot be excluded.

Figures

Text-fig. 4. Praoppiella oanae MIKO et MOUREK gen. et sp. nov. (holotype). A – dorsal view of the body (notogaster largely detached from body, rostral part of prodorsum partly invaginated); B – ventral view; C – dorsal view of detached part of notogaster; D – anterior margin of notogaster as drawed before detachment from the rest of the body; E – bothridium and sensillus. Bars indicating 50 µm (for A,B, C and D, above) and 25 µm (for E, below). For explanation of acronyms see page 31.