Litarachna Walter 1925, sp. nov.
Creators: name: Pešić, Vladimir
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Pontarachnidae
Litarachna

description: Genus Litarachna Walter, 1925
Litarachna lukai sp. nov. (Figs. 2D, 3A–G)
Type series. Holotype male (NIBRIV0000268888), dissected and slide mounted in Hoyer's fluid, South Korea, Yellow Sea, Wido Island, beach, 35º35.089' N, 126º 15.196' E, interstitial, 12.iv.2013 Karanović. Paratypes: one male, one female, same locality and data as holotype, female dissected and slide mounted (NIBRIV0000268889).
Diagnosis: Ocular pigment absent; P-2 with ventrodistal extension; P-2 and P-4 almost equal in length; P-4 stout, with a ventral setal tubercle. Male: Medial apodemes of Cx-IV not extending to anterior margin of genital field; nine pairs of perigenital setae around genital field.
Description. Male: Integument soft, ocular pigment absent (Fig. 2D). Idiosoma L/W 316/191. Coxal field: L/ W 105/152; Cx-I separated medially; suture lines Cx-II/III and Cx-III/IV incomplete; posterior margin of Cx-IV strongly concave, with two pairs of apodemes of moderate length, the medial ones not extending to anterior margin of genital field (Fig. 3A). Genital field L/W 28/28, consisting of a sclerotized ring with three pairs of setae; nine pairs of perigenital setae free in integument around genital field. Between the posterior apodemes of the fourth coxal plates a pair of glandularia-like structures and a pair of small platelets with coxoglandularia 4 and associated setae. Posterior to the genital field a pair of platelets with three pores and three pairs of wheel-like acetabula (sensu Cook 1996). Two of these wheel-like structures large with many radiating spokes, the most posterior ones small with relatively few radiating spokes. Excretory pore unsclerotized, near posterior end of idiosoma. Gnathosoma L 95; chelicera total L 122, claw L 34, basal segment L 90, L ratio basal segment/claw 2.65. Palp (Fig. 3C): total L 201, dL/H, L/H ratio: P-1, 14/22, 0.65; P-2, 60/32, 1.86; P-3, 34/29, 1.16; P-4, 59/20, 2.9; P-5, 34/12, 3.0; dL P-2/ P-4 ratio 1.03; P-2 with ventrodistal extension, ventral margin concave, dorsal margin convexly bowed; P-3 ventrally slightly concave; P-4 stout, ventral margin with a setal tubercle, dividing segment in two parts, distal patr slightly longer than proximal part, both parts with a slightly concave margin. Legs: dL of I-L-4–6 (Fig. 3E): 38, 57, 68; I-L-6 H 22, I-L-6 dL/H ratio 3.04, I-L-6 ventral margin convex; dL of IV-L-4–6 (Fig. 3F): 62–64, 72, 69–73; III-L-5 with one swimming seta; IV-Leg-5 with one swimming setae.
Female: Similar to male, except for the shape of the genital field and postgenital area (Fig. 3B). Idiosoma L/W 354/212. Coxal field: L/W 111/166, medial posterior apodemes of Cx-IV reaching lateral margins of the pregenital slerite. Genital field L/W 55/29, pregenital and postgenital sclerite bowed, postgenital sclerite L 26. Posterior to the genital field a pair of platelets with three pores and four pairs of wheel-like acetabula; three of these wheel-like structures large with many radiating spokes, the most posterior of the wheel-like structures small with fewer radiating spokes. Gnathosoma L 108; chelicera (Fig. 3G) total L 139, claw L 35, basal segment L 108, L ratio basal segment/claw 3.1. Palp (Fig. 3D): total L 221, dL/H, L/H ratio: P-1, 14/22, 0.65; P-2, 68/35, 2.0; P-3, 34/32, 1.05; P-4, 66/23, 2.86; P-5, 39/14, 2.8; dL P-2/P-4 ratio 1.02; palp as in male. Legs: dL of I-L: 36, 29, 41, 42, 62, 70; I-L- 6 H 26, I-L-6 dL/H ratio 2.67; dL of IV-L-3-6: 43, 62, 75, 77; number of swimming setae as in the male.
Etymology. The species is named after Luka Pešić, the three-year old son of the author.
Remarks. The new species belongs to the L. duboscqi species group (see Pešić et al. 2008b). Due to the glandularium-like structur posterior to Cx-IV, not fused with adjoining coxoglandularia 4, and the similar number of perigenital setae (about ten pairs) in the male, the new species resembles Litarachna hongkongensis Smit, 2002, a species described by Smit (2002) from Starfish Bay, Hong Kong. The new species can easily be distinguished from the latter species and other members of the duboscqi -species group by the reduced ocular pigment and ventrodistal edge of P-2 ending in a pointed extension. Moreover, L. hongkongensis has much longer medial posterior apodemes of Cx-IV in the both sexes (see Smit 2002).
Distribution. South Korea (Yellow Sea); known only from the type locality.
description: Published as part of Pešić, Vladimir, 2013, Pontarachnid mites from marine interstitial, with a description of three new species from South Korea (Acari: Hydrachnidia: Pontarachnidae), pp. 83-92 in Zootaxa 3701 (1) on pages 85-87, DOI: 10.11646/zootaxa.3701.1.7, http://zenodo.org/record/284501