Protolimnesia longa Besch, 1963

Pešić, Vladimir, Smit, Harry & Datry, Thibault, 2016, A redescription of Protolimnesia longa Besch, 1963 from Bolivia, with the first description of the female (Acari: Hydrachnidia: Limnesiidae), Zootaxa 4121 (1), pp. 81-84 : 81-84

Protolimnesia longa Besch, 1963

( Fig. 1A–G )

Material examined. Bolivia, Cochabamba Department, unnamed ephemeral stream in the Sacaba area, 17°30'10.43"S,

66°1'51.66"W, alt. 3286 m asl., 03.viii.2015, Karaman-Chappuis digging, leg. Datry, one male, one female, dissected and

slide mounted in Hoyer's fluid.

Morphology. General features. Dorsum with one large postero-medial plate and two pairs of small anterior platelets

( Fig. 1A ); integument reticulate areolate; lateral eyes small and oval, eye pigment reduced; coxae in four separated

groups; Cx-I approaching medially, but separated; glandulae limnesiae centro-medially of anterior margin of Cx-III, not

in the membranous area; Cx-IV with subcutaneous projection at posterior part of medial margin; genital flaps bearing

three pairs of irregular oval, medium-large acetabula; excretory pore smooth; I–III-leg claws bearing strong claws with

distinct clawlets; IV-L-6 bearing strong claws with distinct clawlets and a sub-terminal seta ( Fig. 1C ). Male. Dorsum with rectangular postero-medial plate ( Fig. 1A ). Coxal field ( Fig. 1B ): Cxgl– 4 in antero-medial

region of Cx-III; number of coxal setae: Cx-I, 6; Cx-II, 5; Cx-III, 3–4; Cx-IV, 2; caudal margin of genital field not

reaching posterior margin of Cx-IV, genital field apple-shaped, distance between Ac-1 and Ac-2 slightly larger than distance between Ac-2 and Ac-3, Ac-2 smaller than Ac-1 and Ac-3, Ac-1 and Ac-3 elongated-oval, with a weak central indentation; Ac-2 a bit smaller than Ac-1 and Ac-3, genital plates with two setae anterior of Ac-1, further two setae between Ac-1 and Ac-2, two setae between Ac-2 and Ac-3, one seta in postero-medial corner, as well as some setae lateral to Ac-1, -2 and -3; pre- and post-genital sclerites irregularly elongated-oval ( Fig. 1B ). Palp: P-2 with a heavy, pegshaped ventral seta; P-4 ventral margin with one long seta associated with a tubercle, and two further small setae, each accompanied by a tubercle ( Figs. 1C–D ). Ejaculatory complex with long distal arms and clearly developed proximal arms ( Figs. 1F–G ).

Female. Arrangement of dorsal plates and glandularia as in male, but postero-medial plate almost circular in shape ( Fig. 2C ). Integument structure, shape of coxal field, setae of legs, shape and setae of gnathosoma and palps ( Fig. 2B ) as in male; clear sexual dimorphism in the shape of the genital field. Genital flaps longer, outline appears almost rectangular ( Fig. 2A ); genital field caudally reaching beyond Cx-IV, pre-genital sclerite medium-large; distance between Ac-1 and Ac-2 larger than between Ac-2 and Ac-3; two setae anterior of Ac-1, a further four to six setae between Ac-1 and Ac-2, as well as two setae between Ac-2 and Ac-3, one lateral to Ac-2, and one seta in postero-medial corner of genital flaps.

Measurements. Male. Idiosoma L/W 730/500; postero-dorsal plate L/W 109/95, ratio 1.15; coxal field L/W 383/ 434, ratio 0.88; genital field L/W 131/141, ratio 0.93, pre-genital sclerite W 19; Ac-1–3 L: 42, 31–33, 35–41; ejaculatory complex L 168. Palp: total L 335; L/H, L/H ratio: P-1, 30/37, 0.82; P-2, 94/60, 1.57; P-3, 60/48, 1.26; P-4, 109/32, 3.5; P-5, 42 /17, 2.4; gnathosoma vL 134; chelicera total L 209, H 50, L/H ratio 4.2, claw L 62, basal segment 149, L basal segment/claw ratio 2.4. Legs: dL of I-L: 37, 75, 88, 100, 122, 141; I-L-6 H 34. L/H I-L-6 ratio 4.2; dL of IV-L: 72, 85, 123, 172, 172, 209; IV-L-6 subterminal seta L 51.

Female. Idiosoma L/W 1000/700; postero-dorsal plate L/W 100/106, ratio 0.94; coxal field L/W 390/560, ratio 0.7; genital flaps L/W 153/50, ratio 3.1, pre-genital sclerite W 69; Ac-1–3 L: 38–47, 36, 35–38; egg maximum diameter 231. Palp: total L 340; L/H, L/H ratio: P-1, 29/36, 0.81; P-2, 93/55, 1.68; P-3, 62/46, 1.35; P-4, 111/32, 3.5; P-5, 45/19, 2.4; gnathosoma vL 131; chelicera total L 219. Legs: dL of I-L: 57, 69, 92, 103, 125, 142; I-L-6 H 33. L/H I-L-6 ratio 4.3; dL of IV-L: 111, 89, 119, 171, 217, 194; IV-L-6 subterminal seta L 45.

Remarks. The specimens from Bolivia agree well in general morphology with Protolimnesia longa Besch, 1963 . Protolimnesia longa can easily be distinguished from other members of the genus by a reticulate pattern of the integument, two pairs of medial and anterior dorsal plates and a small genital field. The only difference towards the type specimen from Argentina is found in the almost rectangular shape of the dorsal postero-medial plate in the male from our study compared with the almost circular postero-medial plate in the original description (see Besch 1963, fig. 2).

Habitat. Protolimnesia longa seems to be a characteristic dweller of interstitial waters of ephemeral streams. The sampling site in Bolivia is an ephemeral stream located in the Sacaba area (Cochabamba, Bolivia) ( Fig. 3A–B ). This stream flows about 3–5 months during the year, but species of several aquatic groups such as beetles ( Psephenidae , Dytiscidae ), dipterans ( Stratiomyidae , Sciomyzidae , Ceratopogonidae , Dolichopodidae , Chironomidae ), caddisflies ( Hydroptilidae ) and mayflies ( Caenidae ) are found to be able to survive in the dry sediments (Datry, unpublished data).

Distribution. Argentina ( Besch 1963), Bolivia (this study).

Figures

FIGURE 1 A – G. Protolimnesia longa Besch, 1963, male: A = idiosoma, dorsal view; B = coxal and genital field; C = IV-L- 6; D = palp, medial view; E = palp, lateral view; F = ejaculatory complex posterior, G = ejaculatory complex anterior. Scale bars = 10 0 µm.

FIGURE 2 A – C. Protolimnesia longa Besch, 1963, female: A = coxal and genital field; B = palp, medial view; C = dorsal posteromedial plate. Scale bars = 100 µm.

FIGURE 3 A – B. Unnamed ephemeral stream the Sacaba area (Cochabamba, Bolivia) during the dry (June 2014, Fig. A) and wet (February 2015, Fig. B) season.