Rhynchaturus dispar, Smit, 2021

Smit, Harry, 2021, New records of water mites from Chile (Acari: Hydrachnidia), with the description of three new species, Acarologia 61 (2), pp. 274-290 : 283-285

Rhynchaturus dispar n. sp.

Zoobank: 3F196885-9CB1-44A9-BABA-D83868441D76

( Figure 4 A­C)

Material examined. Holotype female, small stream crossing road W­480, W of Pidpid, prov. Chiloé, Chile, 42°23.545 ′ S 73°51.911 ′ W, 100 m a.s.l., 21 Dec. 2018 (RMNH). Paratypes: two females, same data as holotype (RMNH).

Diagnosis. Dorsum with two pairs of lateral platelets and three pairs of medial platelets; idiosoma with distinct posterolateral tubercles; genital field with three pairs of acetabula.

Description. Female: Integument rugose, idiosoma dorsally 575 (591) long and 535 (543­551) wide, ventrally 688 (705­709) long, with a pair of large posterolateral glandularia tubercles. Dorsal shield with a pair of anteromedial platelets with the postocularia, a pair of posteromedial platelets each with a glandularium, a pair of large central platelets without glandularia and two pairs of lateral platelets, each with a glandularium ( Figure 4A ). Dorsal projection of camerostome pointed, extending just beyond the tips of Cx­I. Gnathosomal bay U­shaped, with a short posterior cleft. Gnathosoma attached to a long protrusible tube. Suture lines of coxae indistinct. Between the coxae a chitinized area, interrupted by a narrow lineated non­chitinized area. Cxgl­4 lying on Cx­IV. Genital field with three pairs of acetabula, the posterior pair partly lying under a sclerotized bar ( Figure 4B ). Gonopore 188 long, genital field approximately 140 wide. Length of P1­5: 14, 50, 34, 60, 42. Palp stocky, especially P4 (Figure

4C); P4 anteroventrally with two fine setae and one anteromedial seta. Length of I­leg­4­6:

132, 128, 76. Length of IV­leg­4­6: 161, 160, 120. Leg claws with large dorsal and ventral clawlets, legs without swimming setae.

Male: Unknown.

Etymology. The epithet dispar comes from the Latin, and means unlike or dissimilar (see below).

Remarks. The female of the new species lacks a pair of small platelets posterior to the pair of large central platelets. This pair of small platelets is present in all known females of the genus except for R. projectus Cook, 1988 , described below. The female of R. projectus Cook,

1988 lacks also such a pair of small platelets, but this species has four pairs of acetabula instead of three pairs.

Figures

Figure 4 Rhynchaturus disparn. sp., holotype female. A – dorsum; B – venter; C – palp. Scale bars: A­B = 100 µm; C = 50 µm.