Paroppia patagonica n.

Kun, M. E., 2012, The Genus Paroppia (Acari: Oribatida) In The Neotropical Region: Paroppia Patagonica N. Sp. From Andean Forests Of Northwestern Patagonia, Argentina, Acarologia 52 (4), pp. 411-418 : 412-417

Paroppia patagonica n. sp.

Measurements — Length of body: 262 – 294 µm, Width of body: 126 – 149 µm

Prodorsum ( Figs. 1a, 1d , 2a, 2c, 2d , 3a ) — Rostrum somewhat narrow, with a hyaline lip, short and barbulated rostral setae, longer than their mutual distance, exceeding by less than one quarter of their length the tip of the rostrum, with alveoli united by a small transverse ridge; lamellar setae located in the middle of prodorsum; no lamellar lines; rostral, lamellar, inter-lamellar and exobothridial setae decrease in size in this order; lamellar setae almost as long as the rostral setae and longer than their mutual distance; inter-lamellar setae are two thirds as long as the lamellar setae and shorter than their mutual distance; exobothridial setae thick, very small and less than one fifth of the length of inter-lamellar setae, exobothridial surface covered with granules; four parallel pairs of interlamellar sigillae, first pair anterior external and smaller than the others, second pair internal greater than the others, third and fourth pairs smaller than second but bigger than first, all forming a distinct T shape; bothridia borders provided with two or three sub-parallel striae, less defined anteriorly and longitudinally grooved posteriorly; groove continued outside the bothridium by a slit curving outwardly and bordered anteriorly by a granulated region ( Fig. 2c ), and posteriorly by a postbothridic apophysis according to Grandjean (1960) ( Fig. 1c ); shortly aciculated elongated fusiform sensilla with pointed tip.

Gnathosoma ( Figs. 2a, 2b ) — Subcapitulum anarthric, imperfectly protected by the rostral tectum when retracted, with pantelebasic rutella ( Grandjean 1957), elongated without teeth, rectangular, forming distally elongated laminae with dorsal deep notch, ventrodistal angle with a small notch; chelicerae elongated with both movable and fixed digits, each with two sharply hooked teeth, incurvation opposed between digits, tightly locking at rest ( Fig. 2a ).

Notogaster ( Figs. 1a, 1b, 1c , 2d , 3a ) — Notogaster oval, smooth, anterior margin pointed and protruding on the prodorsum; posterior margin of male pointed ( Figs. 1b , 2d ), female rounded ( Fig. 1a ); ten pairs of setae, nine pairs scanty distally barbulated, approximately similar in length, setae p1 thinner than the others and pointing outwards from the longitudinal body axis, setae c2 about one sixth as long than the others, represented by microsetae just parallel and internal to lyrifissure ia, insertions of setae lm, lp and h2 slightly anterior to corresponding insertions of la, h3 and p3 respectively; lyrifissure im anterior to setae h3.

Ventral region ( Figs. 1b , 2b , 3b ) — Epimeral border III absent; epimera III and IV fused, with weak alveolar sculpturing, epimeral setae formula 3-1-3- 3; space between epimera II concave, epimeral setae smooth and thin, 1c and 4c longer than the others; acetabula IV situated behind epimeral border IV ( Grandjean 1952, Norton and Behan-Pelletier 2009), genital plates smaller than anal ones, four pairs of small and thin genital setae, one pair anterior near median line, one pair median on each plate and two posterior pairs aligned perpendicularly to longitudinal body axis near posterior margin; two anal setae smooth and thin; adanal setae ad3 located in preanal position, ad 1 in postanal position; lyrifissure iad paraanal and flanked by setae ad2, surface of this region smooth without distinct sculpturing.

Legs ( Figs. 4 , 5 ) — Legs slender, monodactylous, chaetotactic formulae I: 1-5-2(1)-4(2), 18(2)-1, II: 1-5- 2(1)-4(1)-13(2)-1, III 2-4-1(1)-3(1)-13-1, IV 1-2-2-3(1)- 10-1. The solenidia classified according to Grandjean (1935) are tactile solenia: σ I, Φ 1I, Φ IV; baculiform solenidia ω 1I, Φ 2I, σ II, σ III, Φ III; ceratiform solenidia ω 2I, ω aII, ω pII, Φ II; tibia I extended into a long process bearing distally solenidion Φ 1I and basally solenidion Φ 2I.

Type Material — Holotype female and two paratypes, one female and one male from Cerro Padre Laguna 18-X-2006, 41°22’00"S, 71°31’05"O, Río Negro Province, Argentina. Specimens fixed in 50 % ethylic alcohol-lactic acid, mounted in Hoyer’s medium, will be deposited in the Acari Collection at Museo de La Plata , La Plata, Argentina. Five gold sputter-coated paratypes together with 7 paratypes stored in 2 parts of 80 % ethylic alcohol - 1 part lactic acid, will be kept at the laboratory of the Zoology Departament of Centro Regional Universitario Bariloche (Universidad Nacional del Comahue).

Remarks — This species can be clearly separated from other Paroppia by the following combination of characters: tip of the rostrum with hyaline lip, sensillus with elongated aciculated fusiform head and with pointed tip, four pairs of sigillae between interlamellar setae forming a t-shaped array, seta c2 present but very short. P. patagonica n.sp. shares with P. lebruni and Taiwanoppia (Paragloboppia) senegalensis ( Mahunka, 1975) , formerly included under the genus Paroppia (cf. Mahunka 1992), four pairs of genital setae and the tibia I extended into a long process at the end of which tactile solenidion Φ 1I is placed. The solenidion Φ 2I inserted at the base of the tibial process is thick and spiniform (baculiform type) in P. patagonica , while in P. lebruni and T. senegalensis it is setiform (ceratiform type). The sensillus of T. senegalensis with short stem, long erected aciculae, head widened sub-globose distally pointed and exobothridial setae longer than c2 separates T. senegalensis from P. patagonica n.sp. Excluding P. lebruni , all Paroppia species share apparently anarthric subcapitula. According to former generic keys of Subfamily Oppiinae (Subias and Balogh 1989; Balogh and Balogh 1992), the old subgenus Vietoppia (Paragloboppia) , established today as Taiwanoppia (Paragloboppia) (see Subías 2004, Subías 2011), has five pairs of genital setae. Conflicting keys leading to subgenus Taiwanoppia (Paragloboppia) should be revised because T. senegalensis has only four pairs of genital setae. Reassigning T. senegalensis to Paroppia senegalensis based on the unique tibial process, the aciculated sensillus and the four pairs of genital setae, could be a possible outcome after thorough revision of other Taiwanoppia species. Although chelicerae are not pelopsiform in P. patagonica , the uncommon shape of the anarthric subcapitulum with narrow pantelebasic rutella suggests a transition to the suctorial type ( Grandjean 1957). The rather disjunct generic distribution suggests Paroppia is an old taxon with a Gondwanan origin.

Figures

FIGURE 1: Paroppia patagonica n. sp. (SEM): a – female dorsal view; b – male ventral view; c – lateral view; d – partial view of prodorsum (otherwise indicated bar = 100 µm).

FIGURE 2: Paroppia patagonica n. sp. (SEM): a – lateral view of camerostome; b – ventral view of camerostome; c – pseudostigmatic organ; d – male dorsal view (otherwise indicated bar = 100 µm).

FIGURE 3: Paroppia patagonica n. sp., female: a – dorsal view; b – ventral view.

FIGURE 4: Paroppia patagonica n. sp., female. Right Legs I-IV Antiaxial view.

FIGURE 5: Paroppia patagonica n. sp., adult. Antiaxial view of right leg I (SEM).