Mixozercon borealis, Díaz-Aguilar, Irma & Ujvári, Zsolt, 2010

Díaz-Aguilar, Irma & Ujvári, Zsolt, 2010, New zerconid mites (Acari: Mesostigmata: Zerconidae) from Canada, with a review of the genus Mixozercon Halašková, 1963, Zootaxa 2555, pp. 1-29 : 12-15

Mixozercon borealis sp. nov.

( Figures 12–15 , 23 , 27 , 31 , 35 )

Material examined. Holotype: female collected in stand 902- MX, plot 6 (56° 45' 44.754'' N, 118° 24' 53.369'' W) at EMEND research study site, southwestern area, from vascular plants and leaf-litter on forest floor, 10.09.2006, leg. Díaz-Aguilar, I. (deposited in CNC). Paratypes: stand, plot, sampler and sampled season same that of the holotype (2 females, 1 male deposited in CNC, 1 female deposited in HNHM); stand 902- MX, plot 1, southwestern area, from vascular plants and leaf-litter on forest floor, 10.09.2006, leg. Díaz- Aguilar, I. (1 female deposited in CNC, 1 female, 1 male deposited in HNHM); stand 918-CD, plot 6, northern area, from mosses and needle leaf-litter on forest floor, 7.09.2006., Diaz-Aguilar, I. (1 female deposited in HNHM, 1 male deposited in CNC); stand 918-CD, plot 3 and 6, northern area, from mosses and needle leaflitter on forest floor, 07.09.2006., Diaz-Aguilar, I. (15 females); stand 902- MX, plots 1, 3 and 6, southwestern area, from vascular plants and leaf-litter on forest floor 10.09.2006, Díaz-Aguilar, I. (24 females, 5 males).

Diagnosis. Adult female. Central and submarginal setae of podonotum smooth, except j1. Setae J1, Z1, Z5 and marginal R2-R8 smooth, R1 slightly barbed, other opisthonotal J-, Z- and S-setae pilose to varying degrees. Central members of J and Z setal-row inserted in extraordinarily enlarged setal bases, J5 situated between dorsal cavities, Z3 reaching the bases of Z4. Setae S1 situated close to Z1, in posterolateral position. Pores Po2 situated on a line connecting Z1 and Z2. Podonotum covered by circular, irregular-squamous pattern, area between J setal-rows densely ornamented by triangular protuberances. Dorsal cavities weakly sclerotised, with undulate anterior margin. Posterior end of peritrematal shield truncate, reaching the level of R2. Post-genital sclerites absent.

Description. Female. Length of idiosoma 342–368μm (mean 360); width 260–275μm (mean 270) (n = 7).

Dorsum ( Figs 12 , 23 ). Podonotum with 22 pairs of setae: j-row with six pairs, z-row with two pairs, s-row with six pairs, r-row with six pairs, p-row with two pairs. Setae j1 barbed, s3 elongate, pilose, other j-, z- and s-setae short, smooth and needle-like. Marginal setae r3 and r6 elongate, plumose, other r setae shorter and delicately pilose. Peritrematal seta p1 short and smooth, and p2 elongate and pilose; both visible in dorsal view. Pores po1 situated medial to s1, po2 lying on a line connecting j4 and s4, po3 on a line connecting s5 and s6. Whole podonotum covered by small, circular, irregular-squamous pattern ( Fig. 35 ). Circular markings between setae z2 well-developed. Opisthonotum ( Figs 27 , 31 ) with 23 pairs of setae: J-row with six pairs, Zrow with five pairs, S-row with four pairs, R-row with eight pairs. Anterior J setae situated close to each other, J and Z setal-rows widely separated. Setae J1 shorter than other J-setae, smooth, situated close to each other, distance between their bases 21 μm. Setae J2-J5 similar in shape and length, pilose and pointed, tips not reaching the bases of the following seta. Setae J5 situated between dorsal cavities, extending beyond posterior margin of idiosoma. Setae J6 elongate, plumose. Setae Z1 similar in shape and length to J1, Z2-Z3 pilose, Z3 reaching base of the following seta. Z4 elongate, brush-like, distally expanded, Z5 short and smooth. Setae S1 slightly barbed, adjacent and posterolateral to Z1; distance between their insertions 15 μm. Setae S2-S4 elongate, densely plumose, extending beyond the margin of idiosoma. Setae S2 situated anterolateral to Z2.

Marginal R1-R8 setae short, smooth and thorn-like, R 1 may be delicately pilose. Setae J1-J5, Z1-Z4 and S1 inserted on enlarged protuberant setal bases. Pores Po1 situated anterior to Z1, Po2 on a line connecting insertions of Z1 and Z2, Po3 small, lying on a line connecting J4 and Z4, near Z4, Po4 on a line connecting Z5 and S4. Lateral parts of opisthonotum densely covered by large, distinct, bulging spots, central area around J setae with distinct, subtriangular protuberances arranged in circles, forming a stellar pattern. Dorsal cavities weakly sclerotised, uniform, with undulate anterior margin and with axes parallel to that of the body. The length of opisthonotal setae and the distances between their insertions as in Table 3 .

Venter ( Fig. 13 ). Slit between the peritrematal shield and the body margin relatively narrow. Posterior ends of peritrematal shield truncated, straight, reaching beyond the level of R1. Peritremes straight or slightly curved. Post-genital sclerites absent. Anterior margin of ventri-anal shield with two pairs of setae. Pre-anal setae short simple, post-anal seta elongate, distally pilose. Ventri-anal pores situated lateral to adanal setae. Sternal shield with reticulate ornamentation, ventri-anal shield covered by squamous pattern.

Male. Length of idiosoma 277–290μm (mean 285); width 195–202μm (mean 200) (n = 3).

Chaetotaxy, poroidotaxy and sculpturing pattern of dorsal ( Fig. 14 ) and ventral ( Fig. 15 ) shields similar to those on the female, J and Z setae less pilose. Sternogenital shield with straight posterior ending, bearing five pairs of setae. Peritrematal shield and ventri-anal shield fused laterally at the level of setae R2, not separated from body margin. Post-genital sclerites absent. Anterior margin of ventri-anal shield with two pairs of setae ( Fig. 15 ). The length of J, Z and S setae and the distances between their insertions as in Table 3 .

Immature stages. Unknown.

Etymology. The name of the species refers to the fact that it was found in the mixedwood boreal forests.

Remarks. Mixozercon borealis is closely related to M. albertaensis and M. jasoniana by the shape of the dorsal cavities and the presence of enlarged setal bases, and also resembles M. stellifer on the basis of the similar sculpturing pattern and the pilosity of the J-, Z-, and S-setae. This species can be distinguished from the other species of the genus according to the features given in Table 4 .

Figures

FIGURE 12. Mixozercon borealis sp. nov., dorsal view of female.

FIGURES 13 – 15. Mixozercon borealis sp. nov. 13. Ventral view of female; 14. Dorsal view of male; 15. Ventral view of male.

FIGURES 21 – 24. Females of the new species, dorsal view, SEM photos (scale bar 100 µm). 21. Mixozercon albertaensis sp. nov.; 22. Mixozercon jasoniana sp. nov.; 23. Mixozercon borealis sp. nov.; 24. Boreozercon emendi sp. nov.

FIGURES 25 – 28. Central surface of opisthonotum of the new species, SEM photos (scale bar 25 µm). 25. Mixozercon albertaensis sp. nov.; 26. Mixozercon jasoniana sp. nov.; 27. Mixozercon borealis sp. nov.; 28. Boreozercon emendi sp. nov.

FIGURES 29 – 32. Lateral surface of opisthonotum of the new species, SEM photos (scale bar 25 µm). 29. Mixozercon albertaensis sp. nov.; 30. Mixozercon jasoniana sp. nov.; 31. Mixozercon borealis sp. nov.; 32. Boreozercon emendi sp. nov.

FIGURES 33 – 36. Central surface of podonotum of the new species, SEM photos (scale bar 25 µm). 33. Mixozercon albertaensis sp. nov.; 34. Mixozercon jasoniana sp. nov.; 35. Mixozercon borealis sp. nov.; 36. Boreozercon emendi sp. nov.

Tables

TABLE 3. Length of opisthonotal setae and longitudinal distances between their bases in Mixozercon borealis sp. nov. (measurements in µm).

I1	female 18	male 13	Z1	female 18	male 13	S1	female 19	male 12
I1-I2	36	26	Z1-Z2	32	25	S1-S2	34	23
I2 I2-I3	23 30	16 22	Z2 Z2-Z3	21 27	14 22	S2 S2-S3	33 46	25 34
I3	22	15	Z3	22	19	S3	36	25
I3-I4 I4	29 23	22 17	Z3-Z4 Z4	26 42	20 28	S3-S4 S4	45 38	40 27
I4-I5	43	33	Z4-Z5	55	37
I5 I5-I6	22 19	17 12	Z5	10	10
I6	37	28