Limnesia (Limnesia) scutata, 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 : 209

Limnesia (Limnesia) scutata sp. nov.

Zoobank: 675C979E-4D74-4624-AD3C-5771101B94A5

( Figure 7 A-E)

Material examined — Holotype male, Lily Pond , Katherine Gorge, Nitmiluk NP, Northern Territory, Australia, 14°18.801′ S 132°28.326′ E, 3 Oct. 2005 ( NTM) . Paratypes: one male, two females ( NTM), one male, one female ( RMNH), same data as holotype.

Diagnosis — Venter of male with extensive secondary sclerotization, incorporating coxae and genital field, extending onto dorsum; Cx-I fused medially; venter of female with a large area of secondary sclerotization posterior to Cx-IV.

Description ─ Male: Idiosoma dorsally 632 (551-624) long and 470 (429-454) wide, ventrally 624 (583-636) long. Integument with irregular, coarse lineation. Postocularia on small platelets, dorsum with a posteromedial platelet ( Figure 7A ), 146 long and 104 wide. Cx-I fused medially, this fused part much shorter than length of gnathosomal bay. Anterior coxae with short apodemes. Venter of male with extensive secondary sclerotization, almost completely covering venter, incorporating coxae and genital field ( Figure 7B ), extending onto dorsum. Young males have less secondary sclerotization, covering less of the venter. Genital field with three pairs of acetabula; gonopore 128 long. Length of P1-5: 18, 94, 68, 120, 36.

P2 with a peg-like seta located somewhat distally, P4 with distinct setal tubercles ( Figure 7C ). Length of I-leg-4-6: 96, 112, 90. Length of IV-leg-4-6: 128, 144, 132. IV-leg-4 with one stiff swimming seta ( Figure 7D ), IV-leg-6 with a subdistal seta, 80 long (but broken off in illustrated leg).

Female: Idiosoma dorsally 802 (729-834) long and 632 (567-680) wide, ventrally 761 (721-818) long. Integument as in male. Dorsum with a small posteromedial platelet, 108

long and 76 wide. Cx-I fused medially, fused part of Cx-I shorter than length of gnathosomal bay. Anterior coxae with short apodemes. Venter with less secondary sclerotization, in young females completely absent, in older females with a large area posterior to Cx-IV which extends somewhat laterally ( Figure 7E ). In older females with a fringe of secondary sclerotization medially of Cx-III+ Cx-IV, and posterior to genital field a small platelet. Genital field 156 long and 144 wide, with three pairs of acetabula. Length of P1-5: 20, 82, 62, 128, 36. Palp as in male. Length of I-leg-4-6: 104, 120, 100. Length of IV-leg-4-6: 154, 168, 143. IV-leg-4 with one stiff swimming seta, IV-leg-6 with a subdistal seta, 92 long.

Etymology — Named for the large secondary sclerotization in the male.

Remarks — No other Australian Limnesia species has such an extensive secondary sclerotization in the male. The group of Australian Limnesia species which do have extensive sclerotization, have the dorsum with large plates and do not have swimming setae.

Figures

Figure 7 Limnesia (Limnesia) scutata sp. nov., A-D holotype male, E paratype female. A – dorsum; B – venter; C – palp; D – IV-leg-4-6; E – venter. Scale bars: A-B, E = 100 µm, C-D = 50 µm.