Corticacarus (Lundbladacarus) magellanicus, Tuzovskij & Stolbov, 2014

Tuzovskij, Petr V. & Stolbov, Vitaly A., 2014, Description of a new water mite species of the genus Corticacarus Lundblad, 1936 from Chile (Acari, Hydrachnidia: Hygrobatidae), Ecologica Montenegrina 8, pp. 34-37 : 34-37

Corticacarus (Lundbladacarus) magellanicus sp. n.

( Figs. 1-7)

Type material: Holotype: female, slide 9889, South America, Chile, Region de Magallanes y de la Antartica Chilena, Provincia de Magallanes, NW of Villa Tehuelche, forest stream (52°05'537"S 71°48'061"W), depth 0.4 m, substrates: stones and mosses, 14. 08. 2014, leg. V. Stolbov . Paratypes (6 females) collected in same locality as holotype .

Additional material: 1 female, Provincia de Magallanes, stream to the south of Punta Arenas city (53°34'29” S 70°56'23” W), substrates: stones and mosses, 08.11. 2014, leg. V. Stolbov .

All specimens are mounted in Hoyer medium. The holotype and the paratypes are deposited in the collection of the Institute for Biology of Inland Waters (Borok, Russia) .

Diagnosis. Female. Dorsal and ventral shields present; setae Fch short, thick; dorsal shield usually bearing 9 pairs setae; coxal plates in three groups; anterior coxal plates completely fused to each other medially but suture line between them present; all genital acetabula subequal in size; P-3 ventral teeth much larger than teeth on P-2 ventrodistal projections; leg claws indented dorsally, with relatively long subequal central and internal clawlets and short external clawlet.

Description

Dorsal and ventral shields present. Dorsal shield ( Fig. 1) elongate (ratio L/ W 1.35 -1.50), usually bearing 9 pairs of setae (Vi, Oi, Oe, Ve, Hi, Sci, Li, Si, C i) and a posterior pair of slit organs (i 5). Setae Oe, Hi, Li and Ci associated with so-called heart-shaped glandularia. Setae Fch thick, short; setae Fp thin, usually free but sometimes their bases incorporated into the anterior margin of dorsal shield. Primary sclerites (four pairs) slightly developed, anterior two pairs larger than posterior two pairs. Setae Le and anterior four pairs of slit organs (i 1 -i 4) situated on soft integument along lateral margin of dorsum. Excretory pore located caudally.

Coxal plates and genital field incorporated into ventral shield ( Fig. 2). Coxal plates in three groups. Capitular bay V-shaped; coxal plates I fused to each other medially but suture line between them present. Sclerites, bearing setae Hv, located on coxal plates II posterolaterally. Anterior coxal group with narrow posterior apodemes directed laterally. Glandularia Pe on the coxal plate IV shifted from suture line between coxal plates III+IV. Genital field subterminal, with three pairs of subequal acetabula; acetabular plates triangular, their outlines are distinct, with 8-9 thin setae each. Gonopore considerably longer than acetabular plates.

Capitulum ( Fig. 3) with moderately long anchoral process and two pairs of subequal anterior setae; rostrum relatively short. Chelicera with large basal segment and short chela ( Fig. 4).

Pedipalp ( Fig. 5) compact: P-1 short, with single short dorsodistal seta; P–2 with long ventrodistal projection, bearing numerous small teeth, with three subequal proximal and two unequal distal short dorsal setae; P–3 ventrally denticulate, with single dorsoproximal spine and two thin dorsodistal setae; P–4 slender, with obtuse ventral protrusion bearing peg-like seta and thin seta near middle of segment, second ventral seta located on half way between anterior ventral seta and end of segment and three thin distal setae; P–5 thin, with two hook-like distal spines and six unequal distal setae. Surface P-2 - P-4 striated. P-3 ventral teeth much larger than teeth on P-2 ventrodistal projection.

Legs without swimming setae. Shape and arrangement of setae on legs I as shown in Fig. 6.

I-Leg-1 with long distoventral seta, I-Leg-2 and I-Leg-3 with sword-like distoventral seta each. I-Leg-5-6 bearing only thin setae. All legs claws ( Fig. 7) with three clawlets, central and internal clawlets nearly equal in length and longer than external clawlet; lamella with slightly convex ventral margin. All claws slightly indented dorsally.

Measurements (n=7). Idiosoma L 455-510; dorsal shields L 405-485, W 275-320; acetabular plates L 78-85, W 65-72; genital acetabula (ac-1-3) L 25-30, 30-35, 25-30; capitulum L 125-140, rostrum L 24-30; cheliceral segments: base L 150-162, chela L 40-48; pedipalp segments (P-1-5) L: 21-30, 70-73, 81-90, 96- 102, 35-37; leg segments L: I-Leg-1-6: 30-35, 45-60, 60-63, 77-84, 78-95, 70-90; II-Leg-1-6: 35-42, 42-55, 54- 65, 84-95, 84-90, 72-90; III-Leg-1-6: 35-48, 48-54, 72-75, 102-115, 108-120, 95-102; IV-Leg-1-6: 78-90, 65- 72, 95-108, 135-145, 150-156, 108-125.

Remarks. The present species is similar to Corticacarus argentinensis Cook, 1988 but differs in the following characters (character states of female C. argentinensis given in parenthesis, data from Cook 1988): the excretory pore located dorsocaudally, Fig. 1 (ventrocaudally); the acetabular plates with distinct outlines, Fig. 2 (without outlines); P-3 with comparatively large teeth, Fig. 5 (with very small teeth, Fig. 8); the leg claws with dorsal indentation, Fig. 7 (without dorsal indentation).

Etymology. The species is named after the Province (Magellan) where it was collected.

Habitat. Running waters.

Distribution. South America ( Chile: Magellan Province).