Axonopsis (Brachypodopsis) omanensis, Smit & Pesic, 2010

Smit, H. & Pesic, V., 2010, New Species Of Water Mites From Oman, With Some Zoogeographical Notes (Acari: Hydrachnidia), Acarologia 50 (2), pp. 151-195 : 179-181

Axonopsis (Brachypodopsis) omanensis n. sp.

( Figures 21 A-G, 28B-C)

Type series — Holotype: male, stream Hatta Pools , Oman, 15.xi.2008, 24°41.165 N 56°09.556 E, alt. 421 m. Paratypes: 2/2/0 (1/1/0 mounted), same data as holotype.

Other material — 0/5/0 (0/1/0 mounted), unnamed stream crossing road to Al Fay , near Ray, Oman, 15.xi.2008, 24°38.703 N 56°06.760 E, alt. 562 m.

Diagnosis — Colour pattern consisting of a light yellowish central area; dorsal shield with an weakly defined ridge on each side extending anterolaterally to the region of the anterior muscle scars; second, third and fourth legs with swimming setae (III-Leg- 5 with 4 swimming setae; IV-Leg-5 with 3 swimming setae).

Description

Male — Dorsal and ventral shields anteriorly fused; dorsal shield L 341 (341), W 263 (269); eye pigment well developed; dorsal shield with seven pairs of glandularia (the seventh pair of glandularia inconspicuous, flanking the excretory pore); postocularia well distanced from anterior margin; colour pattern consisting of a light yellowish central area ( Fig. 28B ); dorsal shield with a weakly defined ridge on each side extending anterolaterally in the region of the anterior muscle scars (shown as broken lines on Fig. 21A ); excretory pore located at posterior end of dorsal shield; ventral shield L 322 (326), W (322); capitular bay L 87 (82); two pairs of glandularia lying between the genital field and insertions of the fourth legs, these relatively close together; three pairs of acetabula, arranged in an arc; width between most lateral pair of acetabula 104 (111); gonopore W 13 (15); palp ( Fig. 21 D-E): palp total L 184 (179), dL: P-1, 27 (28); P-2, 40 (39); P-3, 26 (25); P-4, 66 (64); P-5, 25 (23); %L: P-1, 14.7 (15.6); P-2, 21.7 (21.8); P-3, 14.1 (14.0); P-4, 35.9 (35.8); P-5, 13.6 (12.9); L P-2/P-4 ratio 0.61 (0.61); ventral margin of P-2 convex, distal margin of P-3 with well developed hyaline extensions, P-4 ventrally dilated near insertions of a pair of setae (one hair-like and one relatively heavy seta), and with a more robust spine near distal margin of the segment. Legs: L of I-Leg-3-6: 26 (28), 39 (45), 62 (62), 68 (66); L of IV-Leg-2-6: 65 (66), 44 (51), 68 (65), 79 (78), 69 (74); swimming setae distributed as follows: II-Leg-5 2, III-Leg-4 2, III-Leg-5 4, IV-Leg-4 2, IV-Leg-5 3.

Female — similar to male, except in shape of the genital field ( Fig. 21G ); dorsal shield L 366, W 266; ventral shield L 350, W 331; capitular bay L 83; width between most lateral pair of acetabula 109; gonopore W 38; palp: total L 179, dL and %L (in parentheses): P-1, 27 (15.1); P-2, 40 (22.3); P-3, 25 (14.0); P-4, 63 (35.2); P-5, 24 (13.4); L P-2/P-4 ratio 0.64. Legs: L of I-Leg-2-6: 30, 29, 45, 59, 60; L of IV- Leg-4-6: 61, 72, 71; number of swimming setae on the legs as in the male.

Etymology — The species is named for its occurrence in Oman.

Remarks — Due to the presence of two pairs of glandularia lying between the genital field and insertions of the fourth legs and similar shape of the palp, Axonopsis omanensis n. sp. resembles A. guadaramensis Valdecasas, 1981 , a species described originally from Sierra de Guadarrama (Central Spain, Valdecasas 1981), and later recorded from Greece (Pe˘si´c and Gerecke, 2003). The new species resembles specimens from Greece also in the presence and distribution of swimming setae on the legs. However in A. guadaramensis , according to Valdecasas (1981), all legs are without swimming setae. Most probably, the specimens from Greece therefore represent a species new to science.

The new species from Oman differs from specimens from Greece in its characteristic colour pattern (compare Figs. 28A and B ) and the ridge on each side of the dorsal shield in the region of the anterior muscle scars being less prominent (this ridge more prominent in the specimens from Greece). A further difference is found in the well delineated suture line visible between genital field and ventral shield in the male specimen from Greece.

Distribution — Oman.

Figures

FIGURE 21: Axonopsis omanensis n. sp. (A-F male [A-B, D-F holotype, C paratype], G female): (A) – dorsal shield; (B, G) – idiosoma, ventral view; (C) – genital field; (D-E) – palp; (F) – I-Leg. Scale bars = 100 µm.

FIGURE 28: Dorsal shield: (A) – Axonopsis quadarramensis sensu Pe˘si´c & Gerecke, 2003; (B) – A. omanensis n. sp., male; (C) – A. omanensis n. sp., female; (D) – A. arabica n. sp., female; (E) – A. balneatoris n. sp., male; (F) – Omanaxonopsis arabica n. sp., female.