Hydrodroma angelieri Pešić & Smit, 2022

Pešić, Vladimir & Smit, Harry, 2022, Hydrodroma angelieri (Acari, Hydrachnidia: Hydrodromidae) a new water mite species from Corsica based on morphological and DNA barcode evidence, Acarologia 62 (1), pp. 3-11 : 5-8

Hydrodroma angelieri Pešić & Smit sp. nov.

Zoobank: C279C2A2-E5E5-4C4D-8751-69B75F9BB0DD

Figs. 1 A-F, 2C

Material examined — Holotype ♀ ( RMHN. ACA.P.67573), France, Corsica, Tributary of Ruisseau de Canne , 14 Apr. 2015, leg. Smit (sequenced [ DCCDB058-21 ], dissected and slide mounted [ CCDB38233 E10]) . Paratype: 1 ♀, same place and data as holotype (sequenced [ DCCDB 057-21]; preserved in Koenike fluid [ CCDB 38233 E09], RMNH.ACA.4508).

Diagnosis. Female (male unknown) — Idiosoma large (idiosoma L ˃ 1500, genital plates

L ˃ 200 µm); integument papillae uniform, apically rounded. Genital plates with 69–80 pairs of Ac in at most 5 longitudinal rows. Legs with relatively short claws (L 42-47, ratio claw L/segment 5 L 11-14 %). Leg setae numbers: II-L-posterior 1; III-L-4 posterior 8; III-L-5 posterior 6-7; IV-L-4 anterior 10, posterior 9; IV-L-5 anterior 5-6, posterior 5-6.

Description — Female — Integument papillae distally rounded. Cx-I+II medially separated by a fine membranous line, with a row of long fine setae at medial margins of Cx-I, and posterior margins of Cx-II, -III, and –IV; a few most medial setae on Cx-I inserted on projections. Genital flaps with rounded lateral and concave medial margins. Excretory pore sclerotized. Leg claws without claw blade, with a dorsal clawlet. P-2 with pectinate mediodistal setae; P-4 with a long, pointed dorsodistal extension reaching tip of the slender and elongated P-5.

Measurements (holotype ; in parentheses some measurements of the paratype specimen, n

= 1): Idiosoma L 1615 (1550), W 1560 (1280). Coxal field L 731 (694); Cx-III W 994 (850);

L Cx-I+II 375 (356); Cx-III+IV 400 (375); coxal setae numbers: Cx-I, 29-31 (24); Cx-II, 24

(21); Cx-III, 22 (21); Cx-IV 19 (20). Genital plate L 273 (244), on each plate Ac number 80

(69), with 45 setae, which in the anterior part are solid and flat, in the posterior part hollow.

Egg maximum diameter 141-150, n = 3 (147, n = 2).

Gnathosoma ( Fig. 1F ) vL 322; chelicera ( Fig. 1E ) total L 392, L basal segment 320, claw

80, L ratio basal segment/claw 4.0. Palp ( Figs. 1 D-E) total L 561, dL/H, dL/H ratio: P-1, 52/56, 0.92; P-2, 103/70, 1.47; P-3, 55/75, 0.73; P-4, 241/57, 4.2; P-5, 110/23, 4.8; L ratio P-2/P-4,

0.43. dL I-L: 84, 122, 147, 244, 322, 272; ratio claw L/segment 5 L 13.9%. dL II-L-2-6: 153,

194, 331, 394, 322; ratio claw L/segment 5 L 11.9%. dL III-L-2-6: 166, 203, 327, 394, 344;

ratio claw L/segment 5 L 11.2%. dL IV-L: 134, 209, 303, 448, 469, 409; ratio claw L/segment

5 L 11.1%.

Male — unknown.

Etymology — Named after the French acarologist Eugène Angelier in appreciation of his outstanding contribution to the study of water mite diversity of Corsica.

Discussion — Based on COI data the new species from Corsica seems to be most closely related to Hydrodroma despiciens (Müller, 1776) and H. pilosa Besseling, 1940 . All three species are characterized by relatively small leg claws (L ratio claw/segment 5 <14 %). Presence of only one short swimming seta on II-L-5 (II-L-5 posterior with 8-10 swimming setae in H. pilosa ), makes the new species more similar to Hydrodroma despiciens , a species absence of swimming setae from anterior IV-L-5 and a generally smaller measurements of idiosoma and gnathosoma ( Pešić 2002 ; Gerecke 2017).

Distribution — France ( Corsica).

Figures

Figure 1 Hydrodroma angelieri sp. nov., holotype ♀, Tributary of Ruisseau de Canne, France: A – integument papillae; B – coxal field; C – genital field; D – palp, lateral view; E – palp, medial view; F – gnathosoma; G – chelicera. Scale bars = 100 μm.