Zercon (Zercorientalia), Ujvári, 2011

Ujvári, Zsolt, 2011, A new subgenus and two new species of Zercon C. L. Koch, 1836 (Acari: Zerconidae) from Southeast Asia, Zootaxa 2995 (1), pp. 45-54 : 46-51

Subgenus Zercorientalia subgen. nov.

Type species. Zercon (Zercorientalia) spinosus sp. nov.

Diagnosis. Setae r1 and r3 approximately of equal length, both needle-like, smooth. Setae s2 absent. Third pair of podonotal glands situated anterolaterally to s4 (gds4), second pair of opisthonotal glands medially to S1, anteriorly to S2 (gdS2), third pair of opisthonotal glands near a line connecting Z3 and Z4 (gdZ3).

Remarks. The general appearance of ventral characters in Zercorientalia , such as the shape of the ventral shields, the size and shape of the peritremes, the appearance of the adgenital area, and the number of ventrianal setae, suggests that the group belongs to the genus Zercon . However, the shape and size of setae r3 distinguishes the group from other Zercon species. These setae are smooth and as long as r 1 in Zercorientalia , but longer and pilose, sometimes provided with hyaline sheets, in other subgenera of Zercon . This difference alone would not be enough to define a new subgenus, because gradual variation of setae r3 is a well-known phenomenon among Zercon species , even if the short and smooth character state is an extreme. It is important that Zercorientalia also lacks setae s2, which has not been reported previously in the family, and seems to be a unique apomorphy of the Southeast Asian species presented here. The location of the dorsal gland poroids also shows a unique combination among Zercon species. The third pair of opisthonotal glands is associated with setae Z3 (gdZ3), as can be observed in a couple of other Zercon species as well, while the unusual location of the second pair of opisthonotal glands, associated with setae S2 (gdS2), is a very rare phenomenon within the genus. However, the position of the third pair of podonotal pores is extreme, as it is usually situated near a line connecting the insertions of z5 and s4 or s4 and s5 (gds4), and these pores are never shifted anteriorly to s 4 in any known species of Zercon . These apomorphic characters serve as a good basis for the establishment of a new subgenus of the large and heterogeneous genus Zercon .

Etymology. The latin name "orientalia" refers to East Asia, where species of this group occur. Gender feminine.

Zercon (Zercorientalia) formosianus sp. nov.

( Figs 1–2 , 16–18 )

Specimens examined. Holotype. Female : As-908 – Taiwan, Ilan County, Datong, township, Taroko N.P., Szji, NW slope of Mt. Jianqing, N24° 29.142' E121° 27.294', 1621 m a.s.l., leaf-litter from disturbed secondary broad-leaved forest, 14 October 2009, leg. Dányi, L. & Lazányi, E. Paratype. One female: locality and date as for the holotype. Diagnosis. Ventrianal setae Zv1 absent. Majority of central and submarginal setae of podonotum apically pilose. Setae J1–3 and Z1–2 short and needle-like, other opisthonotal setae elongate. Glands gdZ3 situated on a line connecting insertions of setae Z3 and Z4. Dorsal cavities strongly sclerotized, unequal in size, central pair significantly smaller than lateral pair. Surface of podonotal and ventrianal shields smooth, opisthonotum covered by small alveolar pits. This species is distinguished from the other species of Zercon (Zercorientalia) according to Table 3.

Description. Female. Length of idiosoma: 408–420 µm (414 µm); width: 355–360 µm (358 µm) (n = 2).

Dorsal idiosoma ( Fig. 1 ). Podonotum with 21 pairs of setae (j1–6, z2–6, s1, s3–6, r1–2 and r4–5 inserted dorsally, setae r3 inserted ventrally on peritrematal shields), s2 absent. Setae j2–3, z3, z6, s1–2 and r1–3 short, smooth and needle-like, r4–5 and s6 1.5 –2 times as long as former setae, smooth, the remaining podonotal setae twice as long as the needle-like setae, apically pilose. Glands gds1 situated posteromedial to insertions of s1; gdj4 positioned below line connecting j4 and z4; gds4 laterally to s4. Surface of podonotal shield smooth, only the musclescars can be observed. Opisthonotum with 21 pairs of setae (J1–5, Z1–5, S1–5, R1–6). Setae J1–3 and Z1–2 short, smooth and needle-like, not reaching bases of the following setae of the series. Setae J4–5, Z3–5 and S2–5 similar in appearance, elongate, distally pilose. J4 and Z3 reaching insertion of the following setae of the series. Each Sseta extending beyond margin of idiosoma. Marginal setae medium-sized, bearing 1–2 pili on their central surface or smooth. Length of opisthonotal setae and distances between their insertions as in Table 1. Glands gdZ1 situated anteromedially to insertions of Z1; gdS2 positioned on line connecting Z1 and S1, near S1; gdZ3 on line connecting Z3 and Z4; gdS5 near insertions of S5, in anterolateral position. Marginal serration obtuse. Surface of opisthonotal shield covered by small alveolar pits. Dorsal cavities with simple inner margin, strongly sclerotized, unequal in size, central pair significantly smaller than lateral pair. Axes of cavities slightly converging posteriorly.

Ventral idiosoma ( Fig. 2 ). Triangular slit between peritrematal and dorsal shields fairly wide. Peritrematal shield truncated at level of posterior margin of coxae IV, with a few sutures around peritrematal gland poroid as ornamentation. Peritrematal setae r3 short, similar in shape and length to r1, smooth. Peritremes arcuate, with a dilation near stigmata. Sternal shield well sclerotized, 69 µm long and 55 µm wide at the level of setae st2, with concave posterior margin and well-developed reticulate ornamentation. Endopodal shields extraordinarily wide and strongly sclerotized, especially at level of coxae III. Five pairs of openings of glands gv2 situated on large adgenital platelets. Ventrianal shield with smooth setiform setae, Zv1 absent. Adanal setae inserted on level of anterior margin of anal opening. Jv3–4, adanal setae and postanal seta similar in shape and length, 1.5 times as long as anterior ventrianal setae. Setae Jv5 similar to posterior R-setae, elongate, smooth. Anal valves with vestigial euanal setae. Glands gv3 situated posterolaterally to adanal setae. Surface of ventrianal shield smooth, only a few tiles can be observed on the margin of the shield.

Gnathosoma ( Figs 16–18 ). Situation and length of hypostomal and capitular setae, shape of corniculi and internal malae typical for the family. Medial process of internal malae short, apically bifurcate. Lateral palp trochantral setae apically pilose, h1–3 smooth, h4 and medial palp trochantral setae serrate. Eight Q-lines present along the subcapitular groove ( Fig. 18 ). Epistome ( Fig. 17 ) with a single, long, trifurcate or bifurcate, marginally serrate medial process. The pair of lateral processes situated next to the medial process short, slightly expressed, barely longer than lateral epistomal spines. Fixed digit of chelicerae ( Fig. 16 ) bearing 7–9 teeth, movable digit with 5–6 teeth. Average length of movable digit 48 µm, average of largest width 19 µm, its relative robustness (as a proportion of former values) 0,40 (slender).

Etymology. Name of the new species refers to the old name of the type locality, Formosa.

Zercon (Zercorientalia) spinosus sp. nov.

( Figs 3–15 )

Specimens examined. Holotype. Female: As-866 – Taiwan, Hualien county, Taroko National Park, Hohuan-shan , Siafoukuong ESRI station, pine forest, from leaf-litter, N24 o 09.704’ – E121 o 17.230’, 3008 m a.s.l., 22 May 2008, leg. Dányi, L., Korsós, Z., Lazányi, E. Paratype. One female: As-916 – Taiwan, Hualien County, Xiulin, township, Taroko N.P., Mt. Hohuan, ESRI High Elevation Station , N24° 09.702' E121° 17.216', 2998 m a.s.l., leaf-litter from pine forest, 12 October 2009, leg. Dányi, L. & Lazányi, E.

Diagnosis. Ventrianal setae Zv1 present. Dorsal setae elongate, most apically barbed, except some anterior podonotal setae. Glands gdZ3 situated posteromedial to setae Z3. Dorsal cavities strongly sclerotized, unequal in size, central pair smaller than lateral pair. Posterolateral surface of podonotum and anterior half of opisthonotum covered by tile-like pattern, posterior half of opisthonotum with bulb-like and spine-like protuberances. This species is distinguished from the other species of Zercon (Zercorientalia) according to Table 3.

Description. Female. Length of idiosoma: 516–550 µm (533 µm); width: 422–425 µm (424 µm) (n = 2).

Dorsal idiosoma ( Fig. 3 ). Podonotum with 21 pairs of setae (j1–6, z2–6, s1, s3–6, r1–2 and r4–5 inserted dorsally, setae r3 inserted ventrally on peritrematal shields), s2 absent. Setae z3, s1–2 and r1–2 medium-sized, smooth, other podonotal setae elongate, apically barbed ( Figs 6–7 ). Glands gds1 situated posteromedially to insertions of s1; gdj4 positioned on a line connecting j4 and z4; gds4 on a line connecting s4 and r4. Posterolateral surface of podonotal shield covered by tile-like ornamentation, central and anterior pattern weakly developed, only the muscle-scars can be observed. Opisthonotum with 21 pairs of setae (J1–5, Z1–5, S1–5, R1–6). Opisthonotal setae elongate, apically barbed, except R5–6 smooth, length of setae in each series increasing posteriorly. Setae J1–5, Z1–5 and S2–5 similar in shape ( Figs 8–11 ), distally with several pili, setae S1 and R1–4 bearing one pilus on distal third. Setae J1 and Z1 not reaching bases of the following setae in the series. Setae Z3–4 and S2–5 extending beyond margins of opisthonotum. Length of opisthonotal setae and distances between their insertions as in Table 2. Glands gdZ1 situated anteromedially to insertions of Z1; gdS2 positioned on a line connecting Z1 and S1, equidistant; gdZ3 posteromedial to setae Z3; gdS5 not visible. Marginal serration shallow and obtuse. Anterior half of opisthonotum with pits arranged in a reticulate pattern, posterior half with bulb-like and spine-like cuticular knobs ( Fig. 5 ). Dorsal cavities with undulate inner margin, strongly sclerotized, unequal in size, central pair smaller than lateral pair. Axes of cavities converging posteriorly.

Ventral idiosoma ( Fig.4 ). Triangular slit between peritrematal and dorsal shields fairly wide. Peritrematal shield truncated at level of posterior margin of coxae IV, smooth. Peritrematal setae r3 relatively short, as long as r1, smooth or provided with one pilus distally. Stigmata large, peritremes bent anteriorly. Sternal shield well sclerotized, 76 µm long and 74 µm wide at the level of setae st2, with strongly concave posterior margin and well-developed reticulate ornamentation. Four pairs of openings of glands gv2 situated on large adgenital platelets. Ventrianal shield with smooth and setiform preanal and adanal setae, Zv1 present. Adanal setae inserted at level of anterior margin of anal opening, 1.5 times as long as anterior ventrianal setae. Postanal seta more than double length of anterior ventrianal setae, finely serrate distally. Setae Jv5 similar to posterior R-setae, elongate, smooth. Anal valves with vestigial euanal setae. Glands gv3 situated posterolaterally to adanal setae. Anterior surface of ventrianal shield covered by reticulate pattern, posterior surface smooth.

Gnathosoma ( Figs 12–15 ). Location and length of hypostomal and capitular setae, shape of corniculi and internal malae typical for the family. Medial process of internal malae long, apically bifurcate. Setae h1, h2 and lateral palp trochantral setae pilose, h4 and medial palp trochantral setae serrate, h3 smooth. Eight Q-lines present along the subcapitular groove ( Fig. 15 ). Epistome ( Figs 13–14 ) with a single, long, trifurcate or bifurcate, marginally serrate medial process. The pair of lateral processes situated next to the medial process short, slightly expressed, barely longer than lateral epistomal spines. Fixed digit of chelicera ( Fig. 12 ) bearing 5–6 teeth, movable digit with four teeth. Average length of movable digit 56 µm, average of largest width 25 µm, its relative robustness (as a proportion of former values) 0,45 (slender).

Etymology. The latin word "spinosus" thorny, refers to the posterodorsal ornamentation of the species.

Zercon (Zercorientalia) sinensis Petrova & Taskaeva

( Figs 19–20 )

Zercon sinensis Petrova & Taskaeva, 1968: 1187 ; Petrova, 1977: 598.

Diagnosis. Setae J1 absent. Opisthonotal setae of each row increasing in length posteriorly, Z1, S1 and R-setae smooth, others distally serrate. Glands gdZ3 situated medial to line connecting insertions of setae Z3 and Z4, equidistant. Dorsal cavities of equal size. Surface of podonotal and opisthonotal shields smooth.

Remarks. This species was described from Yunnan Province, China. Unfortunately the original description and drawings are not detailed enough, and information on some characters is lacking, for example the ventrianal chaetotaxy and situation of gland pores. The type specimens were deposited in the collection of the Zoological Museum of the Zoological Institute, St. Petersburg, but are now lost, according to the curator of the collection. However, the location of the third pair of podonotal gland openings (gds4) is illustrated in a subsequent work of Petrova (1977), confirming that Zercon sinensis belongs to the subgenus Zercorientalia . This species is distinguished from the other species of Zercon (Zercorientalia) according to Table 3.

Figures

FIGURES 1–2. Zercon (Zercorientalia) formosianus sp. nov., female. 1. Dorsal view; 2. Ventral view.

FIGURES 5–18. 5–15. Zercon (Zercorientalia) spinosus sp. nov., female. 5. Caudodorsal ornamentation; 6. Seta j4; 7. Seta r3; 8. Seta Z1; 9. Seta S2; 10. Seta Z4; 11. Seta Z5; 12. Chelicera; 13. Epistome of holotype; 14. Epistome of paratype; 15. Ventral view of gnathosoma; 16–18. Zercon (Zercorientalia) formosianus sp. nov., female. 16. Chelicera; 17. Epistome; 18. Ventral view of gnathosoma.

FIGURES 3–4. Zercon (Zercorientalia) spinosus sp. nov., female. 1. Dorsal view; 2. Ventral view.

FIGURES 19–20. Zercon (Zercorientalia) sinensis Petrova & Taskaeva, 1968, female. 13. Dorsal view; 14. Ventral view (modified after Petrova & Taskaeva, 1968 and Petrova, 1977).