Limnesia (Limnesia) pseudomaceripalpis, Smit, 2022

Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, Acarologia 62 (1), pp. 193-222 : 205-207

Limnesia (Limnesia) pseudomaceripalpis sp. nov.

Zoobank: E1653384-8BDD-447D-8239-0A37D8028162

( Figure 5 A-E)

Material examined — Holotype male, Babinda River , Wooroonooran NP, Queensland, Australia, 17°20.484′ S 145°52.113′ E, 16 Oct. 2005 ( QM) . Paratypes: One male ( QM), two males, one female ( RMNH), same data as holotype.

Diagnosis — Cxgl-4 located on Cx-III; fused medial margin of Cx-I relatively long. Male: Genital field relatively short, with 10-12 small setae along lateral margin.

Description — Male: Idiosoma dorsally 701 (697-754) long and 761 (567-616) wide, ventrally 761 (757-810) long. Dorsum with a posteromedial platelet ( Figure 5A ), 112 long and 84 wide. Coxae in three groups, anterior coxae with short apodemes extending onto Cx-III. Fused medial margin of Cx-I relatively long, L = 112 ( Figure 5B ). Cx-II medially with secondary sclerotization, but not well visible as it is covered by the genital field. Cxgl-4 located on Cx-III, well distanced from associated setae. Medial margin of Cx-IV with a pair of posterior projections. Genital field 152 long and 130 wide, with three pairs of acetabula. Third pair of acetabula larger than anterior two pairs. Gonopore slender, 84 long; along lateral margin 10-12 pairs of small setae. Vgl-1 well distanced from Vgl-3. Length of P1-5: 18, 62, 66, 148, 41. P-2 ventrally with a long, thin seta on a very short setal tubercle, P3 medially with a long seta, P4 and P5 slender ( Figure 5C ). Length of I-leg-4-6: 108, 130, 128. Length of IV-leg-4-6:152, 162, 166. Only fourth leg with swimming setae: IV-leg-4 with six, IV-leg-5 with eight swimming setae; swimming setae distributed over nearly the entire length of segments. IV-leg-4 with five large stout setae and three smaller stout setae, IV-leg-5 with three large and three smaller stout setae. IV-leg-6 without a terminal seta ( Figure 5D ).

Female: Idiosoma dorsally 964 (737) long and 834 (616) wide, ventrally 1021 (834) long. Dorsum with a posteromedial platelet, 126 long and 101 wide. Coxae in three groups, anterior coxae with short apodemes extending onto Cx-III. Fused medial margin of Cx-I relatively long,

L = 138. Cx-II medially with secondary sclerotization, but not well visible as it is covered by genital field. Cxgl-4 located on Cx-III, well distanced from associated setae ( Figure 5E ). Medial margin of Cx-IV with a pair of posterior projections. Vgl-1 well distanced from Vgl-3. Genital field 172 long and 164 wide, with three pairs of acetabula; small setae scattered over genital valves. Pregenital sclerite 118 wide. Length of P1-5: 20, 70, 76, 172, 38; palp as in male. Length of I-leg-4-6: 132, 156, 136. Length of IV-leg-4-6: 184, 212, 214. Fourth leg as in male, IV-leg-4 with seven and IV-leg-5 with 9 swimming setae.

Etymology — Named for its resemblance with L. maceripalpis .

Remarks — The new species is most similar to L. maceripalpis . The most striking difference with the latter species is the much shorter male genital field. The male genital field of L. maceripalpis is 244 long and elongated, the male genital field of the new species is 152 long and hardly elongated. The small setae of the male genital field are not situated along the lateral margin in L. maceripalpis . Moreover, Cxgl-4 of the new species are not lying in a bifurcation of Cx-III and Cx-IV, and the fused medial margin of Cx-I is relatively longer. The palps of the two species are very similar, but P2 of the new species stockier compared to L. maceripalpis and P 4 less slender. A third species with a hair-like seta on P2 L is. suraensis

Wiles, 1997 from New Guinea, known in the female sex only ( Wiles 1997b). The latter species has much larger acetabula, a less slender P4 and Cxgl-4 is close to its associated seta.

Figures

Figure 5 Limnesia (Limnesia) pseudomaceripalpis sp. nov., A-D – holotype male, E – paratype female. A – dorsum; B – venter; C – palp; D – IV-leg-6; E – venter. Scale bars: A-B, E = 100 µm, C-D = 50 µm.