Oxyoppia (Oxyoppiella) mustaciata, Kun, 2014

Kun, M. E., 2014, Oxyoppia Mustaciata N. Sp. From Andean Forests Of Northwestern Patagonia And Key To Oxyoppiinae From Argentina, Acarologia 54 (4), pp. 463-472 : 464-470

Oxyoppia (Oxyoppiella) mustaciata N. SP.

Measurements: Length of body 205 – 235 µm, Width of body 101 – 119 µm (number of measured specimens 45). Holotype 225 – 112 µm, Cerro Padre Laguna (Río Negro Province) November 2006, soil under N. antarctica .

Prodorsum ( Figs. 1a , 2 , 4 , 5 ) — Rostrum rounded dorsally but sharp laterally, unilaterally externally barbulated ro setae, length exceeding the distance between their alveoli, and the tip of the rostrum; lamellar setae 3-barbulated, slightly shorter than ro setae, about one third shorter than the distance between their alveoli and located near the middle of prodorsum but slightly nearer to in setae; in setae unbarbulated, shorter than the distance between their alveoli; ex setae one-barbulated longer than in setae; ro, le, ex and in decrease in size in this order; costulae with straight section converging to an abrupt inwards curved tapering section connected to the transcostula by a thin curved stretch ending in the alveoli of le setae; curved section of each costula almost connected to an arched lateral ridge directed outwards and then back toward the external border of prodorsum; two pairs of parallel sigilla between the insertion of the in setae, first anterior pair rounded, second posterior pair oval transversally elongated; one pair of toothlike interbothridial tubercles each opposite and posterior to in setae overlap the anterior margin of notogaster; sensillus with fusiform head, 8-aciculated externally and 11-aciculated internally, longest external acicules nearly as long as sensillus head width, internal acicules very short only seen with SEM microscope; bothridium border parallelly striated, striations well defined anteriorly, extended posteriorly and converging to a bundle closing the ring of bothridium and bundle slit arching backwards toward the notogaster, bordered by a postbothridic apophysis opposite to anterolateral border of notogaster next to humeral process ( Fig. 1 and indicated by an arrow in Fig. 5 ).

Gnathosoma ( Figs. 1 , 3 , 7 ) — Subcapitulum diarthric protected by the rostral tectum at rest with rectangular atelebasic rutella, forming distally short laminae with dorsal deep notch and ventrodistal tooth, oval chelicerae with two barbulated setae, hypostomal setae h shorter than a and m, h smooth, a and m finely barbulated, mentum with a U shaped thick carina.

Notogaster ( Figs.1a , 2 , 5 ) — Oval, smooth, anterior margin rounded, slender humeral processes standing opposite to posterior bothridial bundle and postbothridic apophysis of the abaxial anterior region of epimera 3, posterior margin rounded; ten pairs of thin setae, c2 small and thin, pointing laterally outwards, spiniform with SEM, length less than one sixth of la; insertions of lm, lp and h2 are located behind that corresponding to la, h3 and p3; setae p2 pointing outwards and backwards; lyrifissures ia opening internally to setae c2, im are oblique and anterior to h3.

Ventral region ( Figs.1b , 3 ) — Borders of epimera 4 arched reaching not far than half of the genital shield; epimeric gutters 4 adaxially widening and ending close to the circumgenital opening, sagittal region of epimera connected to the narrow sternal furrow, apodemes 1, 2 and sejugal visible; half apodemes 2 higher than sejugal, epimeral setal formula 3-1-3-3, setae smooth and thin, setae 3b and 4b are the longest; genital plates smaller than anal, 5 pairs of short genital setae, separated in two groups, three anterior and fifth pairs arranged adaxially, fourth pair separated from the midline, one pair of aggenital setae separated and behind the genital plates, three pairs of adanal and two pairs of anal setae, anal and adanal setae 1 or 2-barbulated, ad3 preanal, ad1 postanal, iad in "paraanal" ( Subías & Balogh 1989) position, slightly behind ad2. In the coxisternal region a large scalelike pedotectum I covers nearly all the femoro-trochanteral articulation on first leg ( Figs 5 and 6 ).

Legs ( Fig. 9 ) — Legs moniliform, slender and monodactylous, chaetotactic formula: for setae, from trochanters to ambulacra: I (1-5-2-4-18-1), II (1-5-2-4-13-1), III (2-3-1-3-13-1), IV (1-2-2-3-10-1); for solenidia, from genua to tarsi: I (1-2-2), II (1-1-2), III (1-1-0), IV (0-1-0). The proral setae are lacking on tarsi II, III and IV as occurs usually for other Oppiidae ( Grandjean 1953; Subías and Arillo 1998).

A brief proximal apophysis directed dorsally on trochanter I and other two proximal and laterally directed on femur II, one sharp and the other blunt ( Fig 6 ) and another is typically seen dorsally on trochanter III (Figs. 2,9). In tarsus IV seta pv" is fanlike ( Figs. 8 , 9 ) as it occurs in other Oppiidae ( Lee and Subías 1991) . Setae pl are lacking on tarsi I.

Solenidia according to Grandjean (1935), tactile: σ I, Φ1 I, σ II, Φ III, Φ IV; baculiform: ωa II, ωb II, σ III; ceratiform: ω1, I ω2 I, Φ II and piliform: Φ2 I. Solenidial formula from genua to tarsi: I (1-2-2), II (1-1- 2), III (1-1-0), IV (0-1-0), usual as for other Oppiidae ( Grandjean 1935, Wauthy and Ducarme 2006, Kun 2012).

Remarks — Oxyoppia mustaciata is related to O. suramericana with whom it shares the same biotopes but differs in last having cuspis or lamellar apophysis and straight prodorsum lateral ridges converging to the lamellar cuspis. In O. mustaciata prodorsum lateral ridges are not straight but curved in all their length. O. mustaciata has a unique connection loop between costulae and transcostula involving the insertion of lamellar setae, second pair of translamellar sigilla oval transversally elongated, setae in is unbarbulated (one barbulated in O. suramericana ) shorter and stiff setae c2 (long and curved in O. suramericana ), humeral processes rounded (flat in O. suramericana ), notogastral setae la are anterior to lm and obliquely located (laterally in O. suramericana ), different shape of femoral II proximal apophysis. As it also occurs in other small Oppiidae pl setae are lacking on tarsi I and III. The loss of setae in the legs of O. mustaciata could be related to its small size and presence in edaphic deep soil habitats as was already pointed out for Neoppia discreta and other Oppiidae ( Subías & Arillo 1998) . Coincidently with previous literature about O. suramericana , specimens of O.mustaciata are smaller than those belonging to the sympatric species O. suramericana .

Etymology — Species name refers to transcostula aspect which jointly with le setae seems a moustache.

Figures

FIGURE 1: O. mustaciata n. sp., female. a - Dorsal view; b - Ventral view; bar 100 µm

FIGURE 2: O. mustaciata n. sp. (SEM) – Female dorsal view; bar 100 µm

FIGURE 4: O. mustaciata n. sp. (SEM) – View of prodorsum; bar 10 µm.

FIGURE 5: O. mustaciata n. sp. (SEM) – Lateral view; bar 50 µm. PI pedotectum I.

FIGURE 3: O. mustaciata n. sp. (SEM) – Female ventral view; bar 100 µm

FIGURE 7: O. mustaciata n. sp. (SEM) – View of subcapitulum; bar 20 µm.

FIGURE 6: Oxyoppia mustaciata n. sp. (SEM) – Partial view of prodorsum; bar 10 µm; arrow indicates apophysis on Fe II. PI: pedotectum I.

FIGURE 9: O. mustaciata n. sp. – Right legs I-IV, antiaxial view.

FIGURE 8: O. mustaciata n. sp. (SEM) – Partial view of notogaster bar 20 µm; arrow indicates trochanteral apophysis on right third leg.