Aspidiobates neogeometricus, Smit, 2019

Smit, Harry, 2019, The water mite genus Aspidiobates Lundblad, 1941 from Australia (Acari: Hydrachnidia: Hygrobatidae) with the description of two new species, Zootaxa 4550 (1), pp. 115-122 : 117-118

Aspidiobates neogeometricus n. sp.

( Figures 2 A–F)

Material examined. Holotype female, Whitehead Creek between Bloomfield and Cooktown, Queensland, Australia, 15°46.843 S 145°17.545 E, alt. 184 m asl, 17-x-2014 ( QM) . Paratypes: One male, Whyanbeel Creek, N of Mossman, 16°22.205 S 145°19.633 E, alt. 143 m asl, 15-x-2005 ( RMNH) ; one female, Birthday Creek , Paluma Range NP, Queensland, Australia, 18°58.799 S 146°10.012 E, 21-x-2005 ( RMNH) ; two females, Henrietta Creek , Wooroonooran NP, Queensland, Australia, 17°35.884 S 145°45.548 E, alt. 390 m asl, 19-x-2005 ( RMNH) ; two males, one female, Unnamed creek N of Cape Tribulation, Queensland, Australia, 16°02.409 S 145°27.428 E, alt. 28 m asl, 17-x-2014 ( QM) .

Diagnosis. Genital field with four pairs of acetabula, palp slender; female with six dorsal plates, two pairs of posterolateral platelets, one unpaired medial plate and one large, unpaired anterodorsal plate; male with three dorsal plates, one large anteromedial plate and one pair of lateral plates.

Description. All coxal suture lines indistinct. Cxgl-4 shifted anteriorly beyond the suture line between Cx-III and Cx-IV. Legs without swimming setae. Female: Idiosoma yellowish, 640 (583-672) long and 518 (527-551) wide dorsally and 709 (700-745) long ventrally. Dorsum with six plates, anterodorsal plate being the largest, 348 long and 437 wide, with two pairs of glandularia and the postocularia. Posterior to this large plate another unpaired plate without glandularia and two pairs of lateral platelets, the anterior lateral plate 208 long, the posterior lateral plate 198 long. Genital field with four pairs of acetabula. Gonopore field large, 114 long and 88 wide. Length of P1-P5: 24, 94, 70, 127, 40. P2 without ventral extension, P4 slender with three small setal tubercles. Length of Ileg-4-6: 146, 138, 110. Length of IV-leg-4-6 103, 198, 128.

Male: Idiosoma dorsally 486 (470-486) long and 397 (405-437) wide, ventrally 551 (567-579) long. Dorsum with a large anteromedial plate with three pairs of glandularia and the postocularia, 421 long and one pair of lateral platelets, 172 long. Genital field with four pairs of acetabula, the anterior pair smaller than posterior three pairs in the illustrated male from Unnamed creek N of Cape Tribulation, but not in other males. Gonopore narrow, 60 long and 14 wide. Length of P1-5: 18, 72, 56, 90, 30. P2 with a large, rounded to more rectangular anteroventral extension, P4 with small setal tubercles. Length of I-leg-4-6: 126, 120, 110. Length of IV-leg-4-6: 150, 170, 120.

Etymology. Named for its resemblance with Aspidiobates geometricus .

Remarks. The new species has a similar configuration of the dorsal plates as in A. geometricus , but is easily separated by the four pairs of acetabula (three pairs in geometricus ) and the slender P4 (stocky in geometricus ). Within the genus Aspidiobates , malformations occur regularly in the shape and number of dorsal lateral platelets and number of acetabula (see A. imperfectus ). This is known also in species from New Caledonia (e.g., A. caeruleus K.O. Viets, 1969 , Smit 2002). A female from Birthday Creek for example has one very small lateral platelet, the other three platelets are of normal size.

Figures

FIGURES 2A–F. Aspidiobates neogeometricus n. sp., A–C = holotype female, D–F = paratype male. A =dorsum; B = venter; C = palp; D = dorsum; E = venter; F = palp. Scale bars: A–B, D–E = 100 µm; C, F = 50 µm.