Type material examined. Female holotype and paratypes: 2 females and 1 deutonymph: Romania, Glăvăneşti – Bacău County, pedunculate oak-hornbeam forest with sessile oak, ash and lime tree, from leaf litter, 30.04.1998, leg. N. VASILIU (deposited in the IBRR).

Additional material. One female: Romania, Drislea-Cozancea – Botoşani County, sessile oak forest, leg. O. IVAN; Five females: Romania, Seaca Movileni – Vaslui County, Quercus pedunculiflora and Quercus pubescens (downy oak), leg. N. VASILIU.

Diagnosis. Anterior margin of ventroanal shield with two pairs of setae. Podonotal setae smooth, with the exception of i1, i2 and marginal setae. Setae I1–2, Z1–2 and S1–2 short, with one barb. I3 short, with a few barbs. I4–5 stouter, medium-sized, barbed and with a hyaline sheath. Setae I5 not reaching the insertions of the following setae of the row. I6, Z3–4 and S3–4 elongated, barbed, with hyaline sheath. Z3 reaching the insertion of the next setae. Marginal setae short, the anterior two pairs barbed, others simple. Po3 situated above the line connecting insertions of setae I5 and Z4, equidistantly. Sculpturing pattern of opisthonotum reticulate-punctate. Dorsal cavities saddle-like, with smooth anterior and undulate posterior margins.

Redescription. Female. Length of idiosoma 461 µm in holotype (448–480 µm in 3 paratypes; mean 463 µm); width 352 µm (335–365 µm; 350 µm).

Dorsal side (Fig. 9). Podonotum with 22 pairs of setae: i-row with 6 pairs, z-row with 2 pairs, s-row with 6 pairs, r-row with 6 pairs, p-row with 2 pairs. Setae i1 and i2 serrated, other podonotal setae short (14–33 µm) and smooth. Lateral surface of shield covered by tile-like pattern, central surface with reticulate ornamentation.

Opisthonotum with 22–23 pairs of setae: I-row with 6 pairs, Z-row with 5 pairs, S-row with 4 pairs and R-row with 7–8 pairs. Setae I1–2, Z1–2 and S1–2 similar in shape and length, short, thin and with one barb. I3 short but more barbed. I4–5 longer, stouter, barbed and with hyaline sheath, I6 approximately twice as long as former setae, but similar in shape. Setae I4 reaching bases of setae I5; I5 not reaching next setae of the row. Z3–Z4 and S3–4 longer and stouter than other setae of corresponding row and provided with hyaline sheath at end. Z3 reaching bases of next setae. Marginal setae short, anterior two pairs barbed, following ones simple. Single pair of supplementary marginal setae may be present. Lengths of setae and distances between setal bases as in table 5. Marginal serration of dorsal idiosoma shallow and obtuse. Sculpturing pattern of opisthonotum reticulated on lateral sides, up to bases of I2, Z3 and S3, posterior surface punctuated. Dorsal cavities equal as to their shape, arranged in parallel direction to body axis.

Poroidotaxy. Pores po1 situated axially to line connecting s1–s2, po2 on line connecting i4–s4, po3 lying axially to line connecting s5–6. Pores Po1 located anteroparaxially to bases of setae Z1, Po2 situated below line connecting setae S2–Z2, near S2, Po3 situated above line connecting setae I5–Z4, equidistantly, Po4 located behind insertion of S4.

Ventral side (Fig. 10). Chaetotaxy, poroidotaxy and shape of ventral shields typical for genus Zercon. Peritremes firmly curved. Sternal shield well sclerotized, 77 µm long and 69 µm wide at level of setae st2, with straight posterior margin and reticulate ornamentation. Adgenital platelets with four gland-openings each. Anterior margin of the ventroanal shield bearing two pairs of setae (Vm1 and Vi1). Ventroanal shield with network-type ornamentation anteriorly and punctuation on posterior surface. Ventroanal pores situated posterolaterally to adanal setae.

Deutonymph. Dorsum (Fig. 11). Length of idiosoma: 384 µm; width: 262 µm (n = 1).

Most of podonotal setae similar to that of adults, however, slightly shorter (10–22 µm). Setae r2, r3 and r6 with 2–3 barbs and with hyaline sheath on their tip. Shield covered by tile-like pattern, irregular pits and elevations.

On opisthonotum, setae I1–5 short, with one barb on each of them. In analyzed exemplar setae I4 absent. Shape of setae I6 identical to that of adult forms being barbed and with hyaline sheath at end. Z1–2 similar to I1–5, being short and smooth. Z3–4 similar to I6. Z3 reaching bases of Z4. Z4 exceeding edge of body and together with I6 longest setae of body. Z5 short, barbed, with hyaline sheath at their tips. In S-row, setae S1 short, smooth; S2 short, with one barb and hyaline sheath at end. S3–4 longer, stouter, barbed and distally provided with hyaline sheath, being similar to I6, Z3 and Z4. S3 reaching bases of S4. Marginal setae short, simple and thorn like. Length of setae and distances between setal bases as in Table 5. Sculpture of opisthonotum reticulated up to bases of I3, Z3 and S2; behind line assigned by former setae, surface ornamented by foveolar structure.

Pores Po1 located at exterior of insertion place of Z1. Position of rest of pores similar to that of adults.

Ventral side (Fig. 12). Anterior border of ventroanal plate with two pairs of setae, similarly to adults (Vm1 and Vi1). Surface of ventroanal shield finely covered by reticulated ornamentation.

Differential diagnosis. Zercon similifoveolatus IVAN et CĂLUGĂR, 2004 is closely related to Zercon foveolatus HALAŠKOVÁ, 1969 described from the East Carpathians by the similar ornamentation and chaetotaxy of dorsal shields. The main differences between the two species are shown in Table 6.