Physobates spinipes Hammer, 1962

Fredes, Natalia A. & Martínez, Pablo A., 2016, Revision of Physobates (Acari, Oribatida, Tegoribatidae) and redescription of Physobates spinipes Hammer, 1962 with comments on tegoribatid genera, Zootaxa 4098 (1), pp. 191-200 : 192-197

Physobates spinipes Hammer, 1962

Physobates spinipes Hammer, 1962

Physobates spinipes: Hammer (1962, 74, Fig. 68) Physobates spinipes: Balogh & Csiszár (1963, 465) Physobates spinipes: Covarrubias (1967, 104) Physobates spinipes: Fredes et al. (2009 , 93) Physobates spinipes: Kun et al. (2010 , 39, 26)

Distribution and ecology: This species was recorded in Chile, Argentina and Uruguay. Hammer (1962) described the Type Locality (Petrohué, Chile) vegetation as consisting of low and scattered scrubs or trees, partly beech; in Argentina, it was recorded in El Bolsón ( Balogh & Csiszár 1963) and Llao-Llao ( Kun et al. 2010), localities placed at the same latitude of Petrohué and with similar biotopes; other localities at Argentina are in Pampas region: Miramar ( Fredes et al. 2009), were samples were taken in a sandy, coastal soil, and Laguna de los Padres (this study) in soil and trees of a native wood (see Material and methods section); in Uruguay this species was collected in riparian soils at Department of Río San Luis (Dr. Manuela Sarasola, pers. comm.).

Description. Adult measurements. Range of female length: 300–310mm, width 220–240 mm (n=4); range of male length: 280–290 mm, width 200–210mm (n=6).

Integument. Adults pale brown to bright brown in color. Cuticle smooth with no trace of cerotegument.

Prodorsum. Rostrum rounded and without incisions. Setae ro and le inserted almost at the same level, both are tiny and setiform. Setae in absent. Lamellae broad and fused, forming a subtriangular structure that covers entire prodorsum ( Figs. 1 A, 3A). Sensillus partially covered by the notogaster with an elongated head and tiny bristles; stalk swollen in the middle ( Fig. 1 D).

Gnathosoma. Infracapitulum diarthric modified: mentum expanded covering labiogenal articulation. Hypostomatic setae h setiform and setae m and a barbellate ( Fig. 3 B, white arrowheads). Axillary saccule present. Chelicera chelate-dentate ( Fig. 1 C). Palpal formula: 0-2-1-3-8+1; palpal eupathidium acm fused to solenidion ω.

Lateral aspect. Tutorium blade-like, ending in a series of spicular flakes ( Figs. 3 C, 3D white arrowhead). Tutorium (tu) runs down forming a gutter structure (gu in Fig. 3 D) that folds over acetabulum I and ends in a very reduced blade. This kind of tutorium was not observed in any other related species. Pedotecta I round ( Fig. 3 D); pedotecta II smaller, scale-like. Porose areas Ah and Al inconspicuous.

Notogaster. Oval. Ten pairs of minute setiform notogastral setae. Pteromorphs movable, hinge well developed. Dorsosejugal furrow quite straight. Dorsophragmata fused and tube-like. Octotaxic system developed as saccules located as shown in Figure 1 A. Lyrifissures ia situated on pteromorphs, im posteriad to seta lm, other lyrifissures are inconspicuous. Large postanal saccule present ( Fig. 4 ).

Ventral region. Coxisternal formula 3-1-2-2, all setae setiform, smooth and tiny. Epimeric plate smooth. Circumpedal carina developed; no custodium; discidium present ( Fig. 1 B). Six pairs of genital setae (rarely five: g3 absent in specimens with five pairs), g1-g3 located along the anterior border, but rarely aligned (some variation in number and or position of setae are shown in figure 1C), g 4 in middle, g5-g6 posteriorly. Lyrifissures iad paranal. Ventral setae setiform, tiny and smooth; one pair of aggenital, two pairs of anal setae. Three pairs of adanal setae: ad1 and ad 2 in paranal position and ad3 postanal ( Fig. 1 B).

Legs. Tarsi heterotridactylous. Femora I with ventral carina; genua I and II without ventrolateral spurs; setation I (1-5-3-4-17 +1), II (1-3-3-4-15), III (2-2-1-3-15), IV (1-2-2-3-12) ( Figs. 2 A-E). Legs II very modified: setae l' on genua displaced to a quasi-dorsal position; setae l'' on tibiae thicker and located dorsally; tarsi II a little shorter than tibiae (ratio Ta-Ti: I= 1.4, II= 0.9, III= 1, IV= 1), broad and compressed laterally with spine-like and lateral dens on its borders ( Fig. 3 F); setae it'' ( Fig. 3 F, white arrow) developed as sharp spines; setae pv'' spine like, with three tips and a basal brush ( Fig. 2 D); solenidion ω1 and ω2 inserted in antiaxial position ( Fig. 3 C). Lyrifissures small. Immatures. Unknown.

Material examined. The holotype was deposited in the Zoological Museum, Copenhagen, Natural History Museum of Denmark ( ZMUC), but, unfortunately, the specimen could not be examined. Material analyzed: 6 females and 2 males from Laguna de los Padres Reserve (MACN-Ar 35598), Buenos Aires. The material analyzed will be kept in the Museo Argentino de Ciencias Naturales ( MACN), Buenos Aires, Argentina.

Figures

FIGURE 1. Adults of Physobates spinipes Hammer, 1962; A) Dorsal view; B) Ventral view; C) Chelicera, left, paraxial view; Tg = Trägårdh's organ (displaced from it original position); D) Variation in number and / or position of genital setae (schematic); E) Sensillus, dorsal view.

FIGURE 2. Legs of Physobates spinipes Hammer, 1962; A) Leg I right, antiaxial view; B) Leg IV right, paraxial view; C) Genua, tibia and tarsus II right, paraxial view; D) Detail of seta pv " on tarsus II, left, antiaxial view; E) Leg III left, paraxial view.

FIGURE 3. Adults of Physobates spinipes Hammer, 1962; A) Frontal view; B) Details of gnathosoma in ventral view (white arrowheads point the hypostomatic setae); C) Detail of prodorsum in frontal view; D) Tutorium (tu) in lateral view (white arrowhead points the spicular flakes on the tutorium, gu = gutter); E) Lateral aspect; F) Detail of tarsus II (white arrowhead points to spine-like seta it' ').

FIGURE 4. Optical microscope image of Physobates spinipes Hammer, 1962 in posterior view.