Abelaturus schwoerbeli Pesic & Smit

Pesic, Vladimir, Smit, Harry & Datry, Thibault, 2010, Water mites (Acari: Hydrachnidia) from the hyporheic waters of the Selwyn River (New Zealand), with descriptions of nine new species, Zootaxa 2355, pp. 1-34 : 16-18

Abelaturus schwoerbeli Pesic & Smit sp. nov.

( Fig. 2G–H , 12A–H )

Type material. Holotype: male dissected and slide mounted in Hoyer's fluid. New Zealand, South Island: Selwyn River near Old Bridge, 20.x.2004. Paratypes: 1/0/0, same data as holotype; 1/1/0 (mounted), Selwyn River near Chamberlain's Ford, 04.vi.2004; 1/0/0, Selwyn River near Chamberlain's Ford, 23.v.2005.

Diagnosis. The free glandularium 2 fused with the posterolateral platelet; idiosoma more rounded (ventral shield L/W ratio, 1.07–1.14 in male, 1.2 in female); capitular bay a deep V-shape.

Description. Male (holotype, in parentheses measurements of paratype). Integumental pigment absent; eye pigment reduced; surface of sclerites rugose (as shown in Fig. 2G–H ); dorsal shield ( Fig. 12A ) L 249 (230), W 215 (204); anteromedial plate L 120 (102), W 164 (149); anterolateral platelets bearing a pair of glandularia; posterolateral platelets with one pair of glandularia (in the holotype the lines of fusion of this platelet with glandularium 2, on one side of the body, are well visible); posteromedial plate bearing two pairs of glandularia; anterodorsal portion of ventral shield forming a rectangular hood ( Fig. 12E ); excretory pore located dorsally on a moderately developed terminal tubercle ( Fig. 12G ); ventral shield ( Fig. 12D ) L 319 (294), W 279 (275); capitular bay V-shaped, L 51 (51); tips of first coxae truncate, second and third coxae somewhat pointed; anterior three pairs of coxae with well developed intercoxal slots; projections associated with insertions of IV-L very broad and extending posterolaterally; a short apodeme and a glandularium on each side medial to insertions of IV-L; gonopore located well anterior to the posterior end, L 19 (19), W 10 (8); acetabula difficult to see in the rugose integument but several pairs seem to be present; palp ( Fig. 12B–C ): total L 138 (134), dL: P-1, 19 (19); P-2, 32 (30); P-3, 20 (18); P-4, 45 (44); P-5, 22 (23); %L: P-1, 13.8 (14.2); P-2, 23.2 (22.4); P-3, 14.5 (13.4); P-4, 32.6 (32.8); P-5, 15.9 (17.2); P-4 noticeably swollen and without ventral projections; capitulum ( Fig. 12B ) much longer than high with palp inserted well proximal of tip, ventral L 83 (81); capitulum attached to a tube of soft integument to produce protrusible mouth parts; dL of IV-L-1-6: 38 (29), 51 (49), 20 (21), 25 (25), 28 (25), 43 (39); maximum H of IV-L-2, 23 (22); IV-L-2 L/H ratio, 2.2 (2.2); chaetotaxy of IV-L as illustrated in Fig. 12H ; swimming hairs absent.

Female. Similar to male except for genital field ( Fig. 12F ); dorsal shield L 255, W 231; anteromedial plate L 121, W 163; ventral shield L 344, W 273; capitular bay L 54; gonopore terminal, L 45, W 23; palp (Fig.): total L 135, dL and %L (in parentheses): P-1, 18 (13.3); P-2, 32 (23.7); P-3, 19 (14.1); P-4, 42 (31.1); P-5 24 (17.8); capitulum ventral L 84.

Etymology. Named in the memory of Professor Jürgen Schwoerbel in appreciation of his studies of New Zealand water mites.

Remarks. This is the third known species of the genus Abelaturus Cook, 1983 . The first, A. cornophorus Cook, 1983 was collected in the hyporheic zone of streams on both North and South Islands ( Cook 1983); the second one, A. ogalus Cook, 1991 was collected from driven wells in the vicinity of Nelson, South Island ( Cook 1991). The new species can be distinguished in the glandularia 2 which lie free in the integument in the two aforementioned species, but are incorporated into the posterolateral plate in A. schwoerbeli .

Due to the absence of pointed projections on the margin of the ventral shield the new species resembles A. ogalus Cook (and differs from A. cornophorus Cook ). It differs from A. ogalus in the more rounded shape of idiosoma, with a relatively deeper capitular bay.

Ecology. The material was collected from May to November from perennial-gaining part of Selwyn River, in the costal plain region.

Figures

FIGURE 2 A – L. Photographs of dorsal shield. A— Colobaturus selwynus Pesic & Smit n. sp., female; B— Taintaturus selwynus Pesic & Smit n. sp., male; C— T. rostratus Pesic & Smit n. sp., female; D— Canterburaturus minutus Pesic & Smit n. sp., male; E— C. novaeseelandicus Pesic & Smit n. sp., female; F— C. cooki Pesic & Smit n. sp., female; G— Abelaturus schwoerbeli Pesic & Smit n. sp., male; H— A. schwoerbeli Pesic & Smit n. sp., female; I— Abelaturus cornophorus Cook, 1983, female; J— Piotaturus bovalus Cook, 1983, male; K— Paratryssaturus cantermus Cook, 1983, female; L— Zelandalbia longipalpis Pesic & Smit n. sp., female.

FIGURE 12 A – H. Abelaturus schwoerbeli Pesic & Smit sp. nov., (A – D, H male, E – G female): A = dorsal shield; B = capitulum and palp; C = palp (P- 1 missing); D, F = ventral shield; E = anterodorsal portion of ventral shield; G = posterior part of idiosoma, dorsal view; H = IV-L. Scale bars = 100 μm.