Sperchon rostratus Lundblad, 1969

Ding, Jian-Hua, Sun, Jing-Lan & Zhang, Xu, 2017, A new species of the water mite genus Sperchon Kramer, 1877 from China, with identifying Sperchonrostratus Lundblad, 1969 through DNA barcoding (Acari, Hydrachnidia, Sperchontidae), ZooKeys 707, pp. 47-61 : 51-56

Sperchon rostratus Lundblad, 1969 Figures 10-12, 13-17, 18-19

Material examined.

2 females, Guizhou Province, Fanjingshan National Nature Reserve, an unnamed stream (27°54'06"N; 108°36'44"E), 29 July 2001, coll. Jian-Jun Guo; 1 male and 1 female, Guizhou Province, Leigongshan National Nature Reserve, an unnamed stream (26°21'06"N; 108°12'39"E), 3 October 2005, coll. Xu Zhang; 2 male and 5 females, Anhui Province, Fuxi village, an unnamed stream (30°04'16"N; 118°09'26"E), 8 September 2016, coll. Xu Zhang.

Description.

Male (n = 3): Body oval in shape, 533 (545-576) in length, 432 (441-476) in width, color yellow-brown. Integument with very fine spinules arranged in hexagonal pattern (Fig. 12). Chitinous plates in dorsum and venter well developed as illustrated in Fig. 10 and Fig. 11. All glandularia and O2 surrounded by a platelet. A1 short and smooth, other dorsal setae thin and long. Coxae in four groups, surface of coxae reticulated. ACG 136 (138-152) in length, posterior apodeme indistinct. E2 laterally between ACG and PCG. PCG 194 (204-216) in length, widely separated. E4 absent from CxIII. Distance between anterior end of ACG and posterior end of PCG 329 (347-361). Genital field 135 (142-156) in length, 121 (128-137) in width, with a small and rounded platelet in front. Three pairs of genital acetabula, first and second pairs of acetabula elongate and oval, third pair more or less rounded. Pre- and postgenital sclerite not developed. V1 without accompanying glandularia but on sclerites of medium size. Excretory pore slightly anterior to V2, and surrounded by a well-developed sclerotized ring.

Capitulum with a long rostrum, length 219 (228-236). Chelicera total length 205 (220-227), basal segment length 166 (179-185), claw length 39 (41-42), ratio of basal segment /claw length (4.3-4.4). Dorsal lengths of the palpal segments: P-I, 26 (27-28); P-II, 103 (107-116); P-III, 147 (156-166); P-IV, 152 (161-170); P-V, 36 (39-43). P-I short and without seta. P-II with one thin seta instead of ventro-distal projection. Eight seta on the dorsal and lateral side of the P-II, none of them plumose. The venter margin of P-III without setae, five smooth setae on the lateral and dorsal side. P-IV with two small peg-like setae, one almost in the middle of the segment and with two small setae, another one near the distal end of the segment.

Legs. Dorsal lengths of leg I: I-L-1, 41 (44-52); I-L-2, 62 (69-78); I-L-3, 78 (82-94); I-L-4, 86 (89-97); I-L-5, 100 (110-126); I-L-6, 97 (103-117). Dorsal lengths of leg IV: IV-L-1, 76 (82-90); IV-L-2, 83 (92-104); IV-L-3, 107 (113-126); IV-L-4, 113 (124-138); IV-L-5, 175 (192-201); IV-L-6, 152 (165-178). Ambulacrum with two claws. Claws with protruding claw blade and two small claws, a long dorsal claw and a shorter ventral one (Fig. 16).

Female (n = 8): Similar to male except for the morphology of genital field and the size of idiosoma. Idiosoma 847 (810-905) in length, 583 (536-618) in width. ACG 173 (154-195) in length, PCG 230 (207-264) in length. Distance between anterior end of ACG and posterior end of PCG 410 (388-435). Genital field 168 (139-192) in length, 152 (138-173) in width. Pregenital sclerite crescent-shaped, and more developed than the postgenital sclerite. Infracapitulum length 288 (264-317). Chelicera total length 286 (278-305), basal segment length 231 (221-248), claw length 55 (57-61), basal segment/claw length ratio 4.2 (4.1-4.4). Dorsal lengths of the palpal segments: P-I, 36 (34-45); P-II, 144 (128-166); P-III, 204 (194-225); P-IV, 212 (200-259); P-V, 57 (50-64). Dorsal lengths of the first leg: I-L-1, 57 (48-66); I-L-2, 86 (71-98); I-L-3, 109 (92-127); I-L-4, 120 (107-146); I-L-5, 142 (130-170); I-L-6, 135 (116-154). Dorsal lengths of the fourth leg: IV-L-1, 93 (80-104); IV-L-2, 112 (107-134); IV-L-3, 173 (157-204); IV-L-4, 296 (272-324); IV-L-5, 267 (257-295); IV-L-6, 234 (227-264).

Remarks.

Sperchon rostratus was first described from Burma by Lundblad (1969). However, the description and illustration given in the literature are short and insufficient. The species was subsequently recorded from China (Guizhou Province, Taiwan), Iran, and Turkey ( Smit 1995, Boyaci 2007, Pesic and Vafaei 2009, Pesic et al. 2012, Pesic et al. 2014). Although the species has been reported many times, an illustration of the idiosoma for the male was given only once (from Turkey) ( Boyaci 2007).

Due to the shape of integument, E4 absent from CxIII, P-II with one thin seta, and P-IV with two small peg-like setae, the female from China shows a general conformity with S. rostratus , a species previously reported from China, however, the morphological characters of the male show obvious differences between the specimens in our study and the Turkish specimens. It is obvious that the platelets of the dorsum and venter of S. rostratus are large and close together (Fig. 10-11), but small and arranged loosely in the Turkish specimens (see details of S. rostratus in Boyaci 2007). In addition, the pre- and postgenital sclerites are small in our specimens but relatively large in Turkish specimens, and the pregenital sclerite is somewhat crescent-shaped in Turkish specimens. Additionally, our specimens possess a rounded platelet in front of the genital field, which is absent in the Turkish specimens.

Although there are many differences between the male of S. rostratus in our study and the Turkish specimens, considering most characters of our specimens (eg., the shape of integument, E4 absent from CxIII, P-II with one thin seta, P-IV with two small peg-like setae and same habitat of the female), we attribute the male specimens to S. rostratus . In order to test whether the male and the female are conspecific, we used DNA barcoding technology for S. rostratus . The results are given below (see Results of molecular analysis).

Distribution.

Burma, China (Anhui, Guizhou, Taiwan), Turkey, Iran.