Corticacarus heteroporus, ., 2016

Tuzovskij, Petr V., 2016, A new water mite species of the genus Corticacarus Lundblad, 1936 from Chile (Acari, Hydrachnidia: Hygrobatidae), Ecologica Montenegrina 6, pp. 42-45 : 42-45

Corticacarus heteroporus sp. n.

( Figs. 1-8 )

Holotype: female, slide 9873, South America, Chile, Región de Magallanes y de la Antártica Chilena, Provincia de Tierra del Fuego, Isla Grande de Tierra del Fuego , stream running into Blanko Lake (54º 04’14” S 68º52’ 43” W), 4.11.2015, leg. A. Prokin. Holotype is deposited in the collection of the Institute for Biology of Inland Waters (Borok, Russia) .

Diagnosis. Female. Dorsum with two anterior plates; setae Fch short, thick; capitular bay V-shaped; anterior coxal plates completely fused to each other medially; posterior coxal groups with moderate secondary sclerotization; gonopore longer than acetabular plates, ac-3 much larger than ac-1 and ac-2; anterior and posterior genital sclerite nearly equal in width; surface of anterior plates with a honeycomb-like structure; soft integument of idiosoma with numerous thin spines.

Description (based on single specimen). Dorsum with two anterior plates, ratio L/ W 1.2, their surface with a honeycomb-like structure ( Fig. 1 ). Lateral eyes not in capsules, eye pigment present. Posterior half of dorsum with four pairs of large heart-shaped glandularia. First four pairs of lyriform organs located along lateral margin of dorsum, and fifth pair close to each other and situated caudally.

Coxal plates in three groups ( Fig. 2 ). Capitular bay V-shaped; coxal plates I narrow completely fused to each other medially, suture line between them absent. Sclerites, bearing setae Hv, located on coxal plates II posterolaterally. Anterior coxal group with short, narrow posterior apodemes directed laterally. Posterior coxal groups with moderately developed secondary sclerotization, sclerite bearing seta Sce fused with the posterior margin of the secondary sclerotization on each side. Interspace between anterior coxal group and posterior coxal groups not sclerotized. Glandularia Pe on the coxal plate IV shifted from suture line between coxal plates III+IV. Genital field with three pairs of acetabula, acetabular plates triangular, with 11-14 thin setae; ac-3 much larger than ac-1and ac-2. Gonopore considerably longer than acetabular plates, anterior and posterior genital sclerites nearly equal in size and shape. All coxal plates punctuated. Idiosoma soft with numerous thin spines ( Fig. 3 ).

Capitulum rhomboidal pointed posteriorly, with short anchoral process and two pairs of unequal anterior setae; rostrum relatively short ( Fig. 4 ). Chelicera with long basal segment and short chela ( Fig. 5 ).

Pedipalp ( Fig. 6 ) slender: P-1 short, with single short dorsodistal seta; P–2 with ventrodistal projection, bearing numerous small teeth, with three proximal and two distal short subequal dorsal setae; P–3 ventrally denticulate, with single dorsoproximal spine and two thin dorsodistal setae; P–4 slender, with ventral peg-like and thin seta near middle of segment, single thin dorsoproximal seta and four distal thin setae; P–5 short, with two hook-like spines and six unequal distal setae.

Legs without swimming setae. Shape and arrangement of setae on legs I as shown in Fig. 7 . I-Leg- 1-3 with some thick setae, and I-Leg-4-6 mainly with thin setae. All legs claws with three clawlets, central clawlet longer than internal and external clawlets, the latter equal in length but internal clawlet thicker than external one; lamella with convex ventral margin ( Fig. 8 ).

Measurements (n=1). Idiosoma L 810; anterior dorsal plates L 150, W 125; acetabular plates L 102, W 70; genital acetabula (ac-1-3) L 24, 24, 42; capitulum L 252, rostrum L 60; cheliceral segments: base L 190, chela L 70; pedipalp segments (P-1-5) L: 30, 120, 132, 180, 60; leg segments L: I-Leg-1-6: 60, 70, 90,145, 145, 120; II-Leg-1-6: 60, 78, 95, 150,?,?; III-Leg-1-6: 66, 90, 108, 185, 198, 155; IV-Leg-1-6: 120, 120, 132, 150,?, 220, 160.

Remarks. The present species is similar to Corticacarus patagonicus Besch, 1964 but differs in the following characters (character states of C. patagonicus given in parenthesis, data from Cook 1980): gonopore longer than the acetabular plates, Fig. 2 (more or less of the same length); ac-3 much larger than ac-1 and ac-2 (all acetabula more or less equal in size); the coxal plates I completely fused to each other medially, suture line between them absent (present); the coxal plate IV without a posteromedial projection (with distinct posteromedial projection); the posterior coxal groups with moderate secondary sclerotization, sclerite bearing seta Sce fused with the posterior margin of the secondary sclerotization on each side (with extensive secondary sclerotization, the sclerite bearing seta Sce located on half way between the posterior margins of fourth coxal plate and secondary sclerotization).

Habitat. Running waters.

Distribution. South America ( Chile: Magellan Province).

Figures

Figures 1-3. Corticacarus heteroporus sp. n., female: 1 - dorsal view; 2 - ventral view; 3 – fragment of integument, lateral view. Scale bars: 1-2 = 200 μm, 3 = 50 μm.

Figures 4-8. Corticacarus heteroporus sp. n., female: 4 – capitulum, ventral view; 5 – chelicera; 6 – pedipalp, 7 – Leg I; 8 – claw. Scale bars: 4-5 = 100 μm, 6, 8 = 50 μm, 7 = 200 μm.