Litarachna muratsezgini, Pešić & Durucan & Zawal, 2019

Pešić, Vladimir, Durucan, Furkan & Zawal, Andrzej, 2019, Marine mites (Acari: Hydrachnidia) of the Mediterranean Sea: Descriptions of two new species, key for identification and future prospects, Zootaxa 4585 (3), pp. 501-516 : 505-509

Litarachna muratsezgini sp. nov.

( Figs 2–6 )

Type material. Holotype female ( RMNH), dissected and slide mounted, Turkey, Antalya, Hamit Bey beach, 36.87555556°N, 30.70722222°E, medium coarse sand, 7 m depth, 30.vii.2017 leg. Durucan. Paratypes: one male, two females, two deutonymphs, same data as holotype, one male and one deutonymph dissected and slide mounted ( RMNH) .

Diagnosis. Suture lines Cx-II/III and Cx-III/IV complete; medial posterior apodemes of Cx-IV broad, shorter than the lateral ones, posteriorly not extending beyond the level of posterior genital field margin in female, in male not reaching level of anterior genital field margin.

Descrıptıon. Female (holotype, in parentheses some measurements of paratypes): Integument soft, ocular pigment present. Idiosoma elongated L/W 491/316 (494-503/291-294); coxal field L/W 184/219; Cx-I separated medially; suture lines Cx-I/II and Cx-III/IV complete, suture line Cx-II/III incomplete; posterior margin of Cx-IV with two pairs of apodemes, the medial ones short and broad, the lateral pairs of apodemes longer than medial ones, posteriorly not extending to caudal margin of postgenital sclerite ( Fig. 3A ). Genital field L/W 70/50, pregenital and postgenital sclerite bowed, postgenital sclerite W 49. A pair of small platelets with coxoglandularia 4 and associated setae free in the integument between posterior apodemes of Cx-IV ( Fig. 3B ). Three pairs of wheel-like acetabula sensu Cook (1996) situated posterior to the genital field, V3 (gland and seta sensu Wiles et al. 2002) fused with Lgl-3; excretory pore unsclerotized, near posterior end of idiosoma.

Chelicera total L 164; palp total L 314, dL/H ratio: P-1, 17/21, 0.82; P-2, 102/54, 1.89; P-3, 41/45, 0.9; P-4, 102/30, 3.39; P-5, 52/17, 3.0; dL P-2/P-4 ratio 1.0; P-2 ventral margin concave; P-3 ventral margin concave, P-4 ventral setae not lying at the same level ( Fig. 3E ). Legs: dL of I-L ( Fig. 3C ): 39, 44, 56, 66, 89, 86; I-L-6 H 26, I-L- 6 dL/H ratio 3.3; dL of IV-L-2-6 ( Fig. 3D ): 52, 64, 99, 111, 102; IV-L-5 with one short swimming seta.

Male: Similar to female, except for the shape of the genital field and postgenital area ( Fig. 4 ). Idiosoma L/W 550/456; coxal field L/W 167/231; posterior apodemes of Cx-IV far away from the level of anterior genital field margin. Ring shaped genital plate (L/W 33/36) with 2 pairs of small setae, area around genital field with a dense group of setae ( Fig. 4 ).

Gnathosoma vL 95; chelicera total L 138; palp total L 286, dL: P-1, 16; P-2, 91; P-3, 48; P-4, 90; P-5, 41; dL P-2/P-4 ratio 1.0. Legs: dL of I-L: 41, 34, 52, 63, 84, 83; dL of IV-L: 70, 44, 56, 88, 102, 90; number of swimming setae as in female.

Deutonymph: As in adults but lacking a genital field ( Fig. 5A ). Idiosoma L/W 294/163. Coxal field L/W 117/ 141. Gnathosoma vL 82; chelicera total L 70; palp total L 171, dL/H ratio: P-1, 11/13, 0.87; P-2, 52/28, 1.84; P-3, 22/24, 0.9; P-4, 56/17, 3.3; P-5, 30/11, 2.7; dL P-2/P-4 ratio 0.92; palp ( Figs. 5 B-C) as in adults.

Etymology. The new species is dedicated to Professor Dr Murat Sezgin, who suddenly passed away on 28 July 2017, in a traffic accident. He was the dean of the Fisheries Faculty of the Sinop University ( Turkey), and a team leader of the meiobenthos ecology group who significantly contributed to the study of the Black Sea.

Remarks. Due to the complete suture line Cx-III/IV, the similar shape of the palp with P-4 ventral margin without a projection, and in males, the area around genital field with a dense group of setae, the new species resembles Litarachna communis Walter, 1925 . The latter species can be easily separated from the new species in having longer apodemes of Cx-IV (posteriorly extending beyond the level of posterior genital field margin in female, in male extending beyond the level of anterior genital field margin) with the medial apodemes longer than the lateral ones. Moreover P-4 and P-5 are less slender in Litarachna muratsezgini sp. nov., while P-4 is more bowed.

Biology. One ovigerous female from our material contained one large egg with a maximum diameter of about 190 µm.

Distribution. Turkey (Gulf of Antalya).

Figures

FIGURE 2. Photograph of Pontarachna punctulum Phillippi, 1840, Albufeira, Portugal, posterior ventral surface of idiosoma. Terminology after Tuzovskij, 1987 (in parentheses after Wiles et al. 2002) and Lundblad, 1927. W1, W2 and W3 are “wheellike acetabula”.

FIGURE 3. Litarachna muratsezgini sp. nov., female holotype: A = idiosoma, ventral view (platelet with three pores and wheel-like acetabula indicated by arrows in double magnification); B = genital field and posterior margin of Cx-IV; C = I-L; D = IV-L-2-6; E = palp. Scale bars = 100 µm.

FIGURE 4. Litarachna muratsezgini sp. nov., male paratype: A = ventral view (platelet with three pores and wheel-like acetabula indicated by arrows in double magnification). Scale bar = 100 µm.

FIGURE 5. Litarachna muratsezgini sp. nov., deutonymph paratype: A = idiosoma, ventral view; B–C = palp. Scale bar = 100 µm.

FIGURE 6. Pontarachna turcica sp. nov., male holotype: A = idiosoma, ventral view; B = IV-L; C = I-L; D = palp. Scale bars = 100 µm.