Phreatomideopsis arrenuripalpis Schwoerbel, 1986

Pešić, Vladimir, Cook, David, Gerecke, Reinhard & Smit, Harry, 2013, The water mite family Mideopsidae (Acari: Hydrachnidia): a contribution to the diversity in the Afrotropical region and taxonomic changes above species level, Zootaxa 3720 (1), pp. 1-75 : 64-69

Phreatomideopsis arrenuripalpis Schwoerbel, 1986

( Figs. 41F , 43A–I )

Material examined: Lectotype female, here designated: SMF, coll. Schwoerbel, “Präp. 1563 CHILE CH 291/83 8. Reg. Bio Bio Bach b. Antuco 19.2.1983 hypo. Leg. Schwoerbel”. State: Dorsal shield detached, venter obviously squeezed; left I-L (probably) lost, left III-L-2-6 and IV-L, and right III-L-4-6 detached and lying separate; gnathosoma detached, with chelicera and right palp in oblique position, left palp lying separate, laterally. Paralectotype: Same data as Lectotype, “Präp. 1564”, without indication “hypo”. State: Idiosoma broken into three parts: (1) central coxal field with left part of genital field, left I-/II-L and right IV-L- 1 in situ; (2) frontal and right flank of ventral shield, crushed between lateral eyes, with left III-L-1-3 and IV-L- 1-2 in situ; (3) distal parts of right Cx-I-III with I-III-L in situ. Right IV-L-2-6 and left IV-L-3-6 separate, laterally (left III-L-4-6 obviously lost); gnathosoma detached, with left palp in oblique position; right palp separate, oblique.

Redescription

Female (measurements in parentheses from Schwoerbel 1986): Coloration following Schwoerbel deep reddish brown, on the dorsal shield stronger in lateral parts, weaker in the centre. Idiosoma L/W 500 (520)/(408) – width measurement from slide 1563 impossible (a comparison with the shape of the dorsal shield makes clear that the venter is squeezed). Lateral eyes each with two lenses (following Schwoerbel with dark pigment, now lost) on slightly convex projections at anterolateral edges of ventral shield. Dorsal shield ( Fig. 41F ) L/W 490 (460)/380 (372), with dense fine porosity, but without special marks except for two small, but strong, round apodemes visible as sclerotized knobs medially from the anterior glandularia. Postantenniformia in the anterior part, two further pairs of glandularia in the posterior half. Ventral shield covering the whole venter except for the transverse oval genital field; coxal suture lines in most parts well visible, but indistinct in the medial parts of Cx-I and -II. Tips of Cx-I pointed, a little distanced from frontal margin, tips of Cx-II less pointed, of Cx-III smoothly rounded. Suture Cx- III–IV laterally continuous with a suture extending anterolaterally from III-L- insertion, Cx-IV medial margin touching only in anteriormost point, posteriorly diverging in an inverse V-shape and passing to the nearly oblique posterior margin; distance posterior gnathosomal bay—anterior margin genital bay 260–290.

Genital field transverse, in horizontal position on slide Nr. 1564, L/W 130 (120)/160, in situ directed posteroventrally and therefore probably Schwoerbel’s length measurement reduced. Gonopore long, flanked by a non-porose, but finely structured membranous area medially forming stronger lips. Three elongate acetabula on oval basal sclerites closely lined up in touch in lateral part, laterally flanked by a longish sclerite anteriorly embracing Ac-1 and posteriorly reaching to mid Ac-3, each bearing 3–5 fine setae.

Gnathosoma short and stout, chelicerae strong and robust as described by Schwoerbel. In the slides not well visible due to oblique position.

Palp ( Figs. 43D, F ) robust, P-1 with one dorsal seta; P-2 with slightly concave ventral and strongly bowed dorsal margins, three setae in dorsal and distomedial position; P-3 short and curved, with two distal setae; P-4 short and stout, slightly curved, with straight ventral and slightly bowed dorsal margins, in distal part two fine dorsal setae, distoventral part forming an obtuse, anteriorly directed projection opposing P-5; this projection bearing subapically one fine hair seta, and apically a strong, peg-like seta; dorsally from the peg-seta, a structure similar to a further peg seta, probably built by the protruding segment surface; P-5 with three strong apical claw-like setae and two more slender subapical setae. Palp measurements (given as: SCHW 1563 (SCHW 1564) [original description]: total L 186 (176) [184], L/H, L/H ratio: P-1, 20 (20) [20]/27 (27), 0.74 (0.74); P-2, 48 (40) [56]/42 (42), 1.14 (0.95); P-3, 34 (35) [30]/33 (31), 1.03 (1.13); P-4, 55 (55) [52]/33 (32), 1.67 (1.72); P-5, L 29 (26) [26]/ 14 (15), 2.07 (1.73); P-2/P-4 L ratio 0.87 (0.73).

Legs without swimming setae, I-III-L relatively short and stout; I-III-L-2-3 with rather long distoventral setae. Other setae short and strong, distal margins of I-III-L-4/5 between setae insertions with pointed tips, I-III-L-6 dorsally each with a fine, spatula-shaped hair seta located in a round pit ( Fig. 43H ); IV-L more slender ( Fig. 43I ), setation rather simple.

Leg measurements (given as: slide SCHW 1564 (in parentheses SCHW 1563)): L/H, L/H ratio: I-L: 45 (42.5)/ 32.5 (30), 1.38 (1.42); 45 (42.5)/32.5 (30), 1.38 (1.42); 50/35 (30), 1.43; 55/36.3 (32.5), 1.52; 60 (72.5)/ 37.5 (28.8), 1.60 (2.52); 87.5 (62.5)/ 37.5 (22.5), 2.33 (2.78); II-L: 50 (50)/35 (35), 1.43 (1.43); 55 (57.5)/31.3 (32.5), 1.76 (1.77); 48.8 (47.5)/35 (35), 1.39 (1.36); 60 (57.5)/36.3 (37.5), 1.66 (1.53); 67.5 (65)/37.5 (36.3), 1.80 (1.79); 90 (90)/37.5 (35), 2.40 (2.57); III-L: 55 (52.5)/32.5 (37.5), 1.69 (1.40); 57.5 (52.5)/32.5 (32.5), 1.77 (1.62); 50 (55)/ 35 (33.8), 1.43 (1.63); 62.5 (62.5)/35 (37.5), 1.79 (1.67); 70 (75)/35 (32.5), 2.00 (2.31); 87.5 (90)/35 (32.5), 2.50 (2.77); IV-L: 70 (72.5)/50 (47.5), 1.40 (1.53); 70 (65)/37.5 (36.3), 1.87 (1.79); 65 (62.5)/32.5 (32.5), 2.00 (1.92); 85 (85)/33.8 (33.8), 2.52 (2.52); 100 (103)/31.3 (30), 3.20 (3.42); 113 (110)/32.5 (28.8), 3.46 (3.83).

Remarks: The original description was based on three females from the interstitial habitat of a small stream in a lateral valley in the direction Antuco and Laguna de la Laja ( Chile, region and province Bio Bio, 19./ 20.02.1982). Morphological and ecological characteristics: 2 m wide, 0.4 m deep, velocity 1 m /s. 30 % shadowed by riparian shrub vegetation. Sediment of stones and sand with mosses, conductivity 45 µS/cm, total hardness 1°dH; sampling method not indicated, probably Karaman-Chappuis dig. A “ Typus ” is mentioned in the original description, but neither a designated holotype, nor other specimens with corresponding species name labels could be found in coll. Schwoerbel. However, two slides as cited above were found in his “ Chile ” box which obviously represent two syntypes—we must assume that the third one is lost (differences in measurements and shape of the specimen figured by Schwoerbel suggest that the lost specimen is the one on which he mostly based his description). Notwithstanding some restrictions resulting from the non-perfect quality of slide mounts (in 1563, impossibility to use oil immersion due to too thick mounting medium layer, in both slides oblique position of gnathosoma and three of four palps) we retain the quality of the preparations as sufficient and renounced to risky remounting.

Distribution: Chile (Schwoerbel 1986).

Figures

FIGURE 41 A – H. Photographs of dorsal shield. A – C. Djeboa multidentata K. Viets, 1911: A — male holotype (SMF 43185); B – C — male (SMF 43203). D – E. Mideopsellides geae K. O. Viets, 1962: D — male holotype; E— female paratype; F. Phreatomideopsis arrenuripalpis Schwoerbel, 1986: lectotype female. G – H. Xystonotus madagascariensis sp. nov., female: G = holotype; H = paratype.

FIGURE 43 A – I. Phreatomideopsis arrenuripalpis Schwoerbel, 1986, female: A = dorsal shield; B = genital plate; C = idiosoma, ventral view; D = palp (P- 1 missing); E = P- 4 and - 5; F = palp; G = I-L- 3 - 6; H = III-L- 4 - 6; I = IV-L- 4 - 6.