Litarachna antalyaensis Pešić, Durucan & Chatterjee, 2018

Durucan, Furkan, Chatterjee, Tapas & Pešić, Vladimir, 2018, Two new species of the marine water mite family Pontarachnidae (Acari: Hydrachnidia) from the Gulf of Antalya, Turkey, Zootaxa 4531 (2), pp. 271-278 : 273-277

Litarachna antalyaensis Pešić, Durucan & Chatterjee sp. nov.

( Figs. 2 A–E, 3A–D)

Type series. Holotype male, dissected and slide mounted in Hoyer, Turkey, Antalya, Hamit Bey Plaji , 36.87555556°N, 30.70722222°E, 30.vii.2017 leg. Durucan. Paratypes: two males, three females, same locality and data as holotype, one male and two females dissected and slide mounted.

Comparative material examined. Litarachna duboscqi Walter, 1925 , one male, Turkey, Antalya, Hamit Bey Plaji, 36.87555556°N, 30.70722222°E, 30.vii.2017 leg. Durucan.

Diagnosis: The glandularium-like structure posterior to Cx-IV not fused with adjoining coxoglandularia 4; P-4 stout, with a ventral setal tubercle. Male: Medial apodemes of Cx-IV not extending to anterior margin of genital field; 8–10 pairs of perigenital setae around genital field. Female: Medial apodemes of Cx-IV not extending beyond the posterior margin of genital field.

Description. Male (holotype, in parentheses measurements of paratype): Idiosoma LW 428/340; coxal field L/ W 148 (139)/225 (211); Cx-I separated medially; suture lines Cx-II/III and Cx-III/IV incomplete; posterior margin of Cx-IV concave, with two pairs of apodemes of moderate length, the medial ones not extending to anterior margin of genital field ( Fig. 2A ). Genital field L/W 25 (25)/26 (26), consisting of a sclerotized ring with 4-5 pairs of setae; 8-10 pairs of perigenital setae free in the integument surrounding the genital field. Between the posterior apodemes of Cx-IV 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 two pairs of wheel-like acetabula sensu Cook (1996). One 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 with a short rostrum, L 126; chelicera two-segmented, typically claw-like in form, total L 175 (161); palp: dL/H ratio: P-2, 87/42, 2.1 (83/34, 2.4); P-3, 30/38, 0.78 (30/34, 0.86); P-4, 92/27, 3.5 (84/25, 3.3); P- 5, 30/13, 2.3 (29/12, 2.5); dL P-2/P-4 ratio 0.94 (0.98); P-2 ventral margin concave, dorsal margin convexly bowed; P-3 ventrally slightly concave; P-4 stout, ventral margin with setal tubercle, dividing segment in two parts, distal part longer than proximal part, both parts with a concave margin.

Legs: dL of I-L ( Fig. 3B ): (38), 34 (31), 39 (39), 48 (45), 70 (70), 86 (77); I-L-6 H 23 (27), I-L-6 dL/H ratio 3.7 (2.9), dL of IV-L ( Fig. 3D ): 55 (55), 43 (44), 48 (50), 81 (81), 99 (93), 101 (102); IV-L-5 with two swimming setae, one longer and one shorter.

Female (n = 2): Similar to male, except for the shape of the genital field and postgenital area ( Fig. 2B ). Idiosoma L/W 434/275. Coxal field L/W 156–164/216–228; medial posterior apodemes of Cx-IV not extending beyond the posterior margin of genital field. Genital field elongated L/W 65–69/42–45, pregenital and postgenital sclerite strongly bowed, postgenital sclerite W 38–41. Posterior to the genital field a pair of platelets with three pores and three pairs of wheel-like acetabula; two 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 134–141; chelicera total L 191–192; palp: total L 260–265, dL dL/H ratio: P-1, 16/19–20, 0.77–0.83; P-2, 91–92/47, 1.93–1.96; P-3, 31/41–42, 0.74–0.8; P-4, 92–94/28, 3.27–3.34; P-5, 30–33/14–15, 2.1– 2.14; dL P-2/P-4 ratio 0.97–1.0; palp ( Fig. 2D ) as in male.

Legs: dL of I–L ( Fig. 3A ): 45, 39–41, 39–44, 47–52, 70–77, 88–96; I-L-6 H 27–28, I-L-6 dL/H ratio 3.2; dL of IV-L ( Fig. 3C ): 55, 45, 50–59, 86–94, 96–105, 102–108; number of swimming setae as in the male.

Etymology. The species is named for its presence in Antalya.

Remarks. Litarachna antalyaensis belongs to the L. duboscqi —species group (see Pešić et al. 2008c). Litarachna duboscqi is a widely distributed species in the Mediterranean Sea ( Walter 1925) and can easily be distinguished from the new species in the glandularium-like structure posterior to the fourth coxal plates fused with the adjoining coxoglandularia 4 (compare Fig. 2E with Fig. 2F ).

Due to the medially separated first coxal plates and the glandularium-like structure posterior to Cx-IV not fused with adjoining coxoglandularia 4, the new species resembles Litarachna hongkongensis Smit, 2002 , from Starfish Bay, Hong Kong ( Smit 2002), L. marshalli Wiles, Chatterjee & De Troch, 2002 from the Indian Ocean ( Wiles et al. 2002), L. lukai Pešić, 2013 from the marine interstice of the South Korean coast of the Yellow Sea (Pešić 2013a) and L. sagamiensis Moto & Abé, 2013 from the Pacific coast of Japan ( Moto & Abé 2013). Litarachna sagamiensis differs from the new species in the higher mumber of perigental setae around the male genital field (49–71, data taken from Moto & Abé 2013) and the glandularium-like structure and adjoining coxoglandularia 4 located posteriorly to posterolateral apodeme of Cx-IV ( Moto & Abé 2013). Litarachna lukai is characterized by the reduced ocular pigment and ventrodistal edge of P-2 ending in a pointed extension (Pešić 2013a). Litarachna hongkongensis is similar to the new species in having about ten pairs of perigental setae in the male but differs from the latter in a less elongated genital field in the female with the genital sclerites almost touching each other and much longer medial posterior apodemes of Cx-IV in both sexes (see Smit 2002). Litarachna marshalli can be distinguished from the new species in the male genital field having only three pairs of perigenital setae ( Wiles et al. 2002).

Biology. One ovigerous female from our material contained one large egg with a maximum diameter of about 120 µm.

Distribution. Turkey; known only from the type locality.

Figures

FIGURE 2A–F. A–E Litarachna antalyaensis sp. nov., (A, C male holotype, B–E, D female paratypes): F L. duboscqi Walter, 1925, female. A–B = idiosoma, ventral view (platelet with three pores, wheel-like acetabula and male genital field indicated by arrows in double magnification); C–D = palp; E–F = genital field and posterior margin of Cx-IV (the glandularium-like structure and adjoining coxoglandularia 4 indicated by arrows). Scale bars = 100 µm.

FIGURE 3A–D. Litarachna antalyaensis sp. nov., (B, D male, A, C female): A = Leg I; B = I-L-2–6; C–D = Leg IV. Scale bar = 100 µm.