Limnesia (Limnesia) rubra Smit, 1998

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 : 207-209

Limnesia (Limnesia) rubra Smit, 1998

( Figure 6 A-E)

New records — Northern Territory. 1/1/0, plunge pool Edith Falls, Nitmiluk NP, 14°10.899′ S, 132°11.342′ E, 149 m a.s.l., 2 Oct. 2005.

Description — Male: Idiosoma dorsally 980 long and 802 wide, ventrally 1016 long. Integument with a coarse lineation, chitinized parts brownish. Dorsum with a posteromedial platelet, 122 long and 110 wide. Postocularia on small platelets ( Figure 6A ). Gnathosomal bay about as long as fused portion of Cx-I. Anterior coxae with short apodemes, Cx-I fused medially. Cxgl-4 well separated from associated seta ( Figure 6B ). Genital field 243 long and 243 wide; gonopore broad elliptical, 128 long and 80 wide. Vgl-3 well distanced from Vgl-1. Posterior to genital field and Cx-IV a small area of secondary sclerotization. Length of P1-5:

30, 134, 100, 198, 56. P2 ventrally with a peg-like seta, P4 slender, ventrally with s small setal tubercle ( Figure 6C ). Length of I-leg-4-6: 142, 170, 150. Length of IV-leg-4-6: 215, 227, 210; subterminal seta of IV-leg-6 126 long. Swimming setae: III-leg-4 one, IV-leg-4 three, IV-leg-5 two ( Figure 6E ). III-leg-5 with eight long setae along entire length of segment, which could act as swimming setae ( Figure 6D ).

Female: Idiosoma dorsally 1266 long and 1975 wide, ventrally 1286 long. III-leg-5 with four long setae along proximal half of segment which could act as swimming setae, IV-leg-5 with two stiff swimming setae.

Remarks — The new material from this study is collected on the type locality. According to the original description ( Smit 1998), the gnathosomal bay should be longer than the fused portion of Cx-I. In the new material, the gnathosomal bay is more or less as long as the fused portion of Cx-I. Moreover, the chitinized parts are not as red as in the type material. Apparently,

it is not clear whether the gnathosomal bay of this species is longer than the fused portion of Cx-I, more material is needed to clarify this. Above a more detailed description is given of the male, and some additional characters of the female. Only the long setae of III-leg-5 are flexible. Females without the reddish chitinized parts and a deep gnathosomal bay cannot be separated from L. parasolida , but the long setae on III-leg-5 are absent in the latter species. In the key at the end of this section I used both options for the gnathosomal bay.

Figures

Figure 6 Limnesia (Limnesia) rubra Smit, male. A – dorsum; B – venter; C – palp; D – III-leg-5-6; E – IV-leg-5-6. Scale bars: A-B = 100 µm, C-E = 50 µm.