Pachyseius siranensis, Özbek, Hasan Hüseyin & Halliday, Bruce, 2014

Özbek, Hasan Hüseyin & Halliday, Bruce, 2014, Two new species of Pachyseius Berlese (Acari: Pachylaelapidae) from Turkey, with a key to the world species, Zootaxa 3841 (1), pp. 107-116 : 108-110

Pachyseius siranensis sp. nov.

Diagnosis. Ventri-anal shield bearing two pairs of pre-anal setae; a pair of distinct presternal shields present; metasternal shields free in soft skin; posterior ends of peritrematal shields extending beyond coxae IV and exopodal shield IV; peritrematal shields not fused with exopodal shield IV; metapodal shields well separated from anterolateral margins of ventri-anal shield; postero-lateral soft skin bearing eleven pairs of lateral setae, opisthogastric skin around ventri-anal shield bearing an additional eight pairs of setae.

Specimens examined. Holotype female, Gümüşhane Province, Şiran Town, Çakırkaya Village, 40° 09' 75'' N, 39° 04' 24'' E, alt. 1326 m, 23 April 2012, from litter and moss under Astragalus sp. Paratypes: two females with same data as holotype; one female, Gümüşhane, Şiran Town, Çakırkaya Village, 40° 07' 54'' N, 39° 05' 36'' E, alt. 1279 m, 23 April 2012, from litter under Populus sp.

Description. Female ( Figures 1–6 , 14–15 )

Dorsum ( Fig. 1 ) (n = 4). Dorsal shield 740 (710–750) long, 365 (365–415) wide at widest point, oblong (length/width, 1.76–2.02), ornamented with net-like pattern, and having 30 pairs of pointed needle-like setae, marginal setae longest; a pair of lyrifissures present between j1 and z1; a pair of well sclerotised, wide open cavitylike gland pores gdj3 present between seta z1 and z2; and six to eight pairs of conspicuous postero-lateral pores. Anterior ends of peritremes extending forward beyond level of gdj3. Setae z1 shortest, 10–14; j5, j6, z 5 26–32; z6 52–63; J1 32–35; postero-marginal setae longest, S1–S5 62–67.

Venter ( Fig. 2 ). A pair of well sclerotised presternal shields present. Sternal shield ( Fig. 14 ) 140 (140–160) long, 110 (110–130) wide at the level coxae II; central and posterior region with punctate ornamentation, anterior and anterolateral regions with polygonal lineate ornamentation; shield carrying three pairs of pointed needle-like setae and two pairs of lyrifissures. Length of setae St 1 31–45, St2 32–46, St3 32–43. Metasternal shields small, oval, free in the soft skin, each bearing a metasternal seta (39–52) and a pore. Epigynal shield 130 (130–150) long, 120 (110–120) wide at widest point, ornamented with punctate lines; a row of four elongate platelets along its posterior margin; genital pores situated outside the postero-lateral margins of the shield, genital setae length 36–41. Ventri-anal shield ( Fig. 15 ) longer than wide, 290 (290–310) long, 230 (220–250) wide at the widest point (length/ width, 1.23–1.26), with polygonal and punctate ornamentation, bearing two pairs of long pointed pre-anal setae, Jv2 longest, a pair of shorter para-anal setae, and a short postanal seta. Posterior ends of peritrematal shields rounded, extending beyond posterior margins of coxae IV, not fused with exopodal shields IV, with a pair of large post-stigmatal pores and a pair of smaller pores; width of peritrematal shield at the level of the stigmata about double the width of the peritreme. Opisthogastric skin between peritrematal shields and anterolateral margins of ventri-anal shield with one pair of large oval platelets and two pairs of small circular platelets. Metapodal shields elongated (70 long) and separated from anterolateral margins of ventri-anal shield (10–20). Opisthosomal soft skin bearing 11 pairs of lateral setae, opisthogastric skin surrounding ventri-anal shield bearing an additional eight pairs of setae (length of setae in soft skin 35–65).

Gnathosoma . Corniculi short and horn-like; hypostomal seta h3 longest (56–60 µm), h1 34–36, h 2 20–24, palp coxal seta 20–22; deutosternal groove with five rows of denticles. Palp with 3-tined apotele. Epistome with truncate and denticulate anterior margin ( Fig. 3 ). Cheliceral digits slender, movable digit with two medial teeth and a terminal hook, arthrodial brush short; fixed digit with a single medial tooth, bidentate terminal hook, and fine pilus dentilis ( Fig. 4 ).

Spermathecal apparatus ( Fig. 5 ). Spermathecal tubes long and fine, opening on coxae III.

Legs. Chaetotaxy: Leg I. Coxa 0 0/2 0, trochanter 1 1/3 1, femur 2 5/4 2, genu 2 5/3 2, tibia 2 5/3 2. Leg II. Coxa 0 0/2 0, trochanter 1 0/3 1, genu 2 5/2 2, tibia 2 4/2 2, tarsus 3 7/5 3. Leg III. Coxa 0 0/2 0, trochanter 1 0/3 1, femur 1 3/1 1, genu 2 4/1 1, tibia 1 3/2 1, tarsus 3 7/5 3. Leg IV. Coxa 0 0/1 0, trochanter 1 0/3 1, femur 1 3/1 1, genu 2 4/1 1, tibia 1 3/2 1, tarsus 3 7/5 3. Tarsus II with one large spur like seta ( Fig. 6 ).

Etymology. This species is named after Şiran Town, where it was collected.

Notes. This species is clearly separated from all other European species of the genus in having only two pairs of pre-anal setae on the ventri-anal shield, a pair of well sclerotised presternal shields, metasternal shields free in the soft skin, peritrematal shields not fused with the exopodal shields, and with their posterior ends extending beyond the level of coxae IV. It shares these character states with P. orientalis Nikolsky, 1982 (Primorsky Region, Russia), but differs from P. orientalis in having the ventri-anal shield longer than wide, the metapodal plates well separated from the anterolateral margins of the ventri-anal shield, the different shape of the epistome, and the size and shape of the dorsal shield. In P. siranensis the posterior end of the peritrematal shield is narrow, while that of P. orientalis is greatly expanded. In P. siranensis the ventri-anal shield is less than double the width of the epigynal shield, while that of P. orientalis is more than 2.5 times the width of the epigynal shield.

Pachyseius siranensis also shares many important character states with P. crymophilus Mašán & Fenďa, 2014 , but may be distinguished from it in having only two pairs of setae on the ventri-anal shield (three in P. crymophilus ), and in having dorsal shield seta j1 of normal length, much longer than z1. In P. crymophilus , seta j1 is very short, similar in length to z1.

In P. siranensis , as in several other species in this genus, there is some ambiguity about the number of setae on the ventri-anal shield. We have described it as having two pairs, Jv1 and Jv2. A third pair, Zv2, lies in the unsclerotised soft skin very close to the edges of the ventri-anal shield, postero-lateral to Jv2. This pair of setae may appear to be on the shield on one or both sides, due to variation in the degree of stretching or folding of the soft skin.

Figures

FIGURES 1 – 6. Pachyseius siranensis sp. nov., female. 1. dorsal shield; 2. ventral idiosoma; 3. epistome; 4. chelicera; 5. sperm access system; 6. leg II (tibia-tarsus). Scale bars: 200 µm for 1, 2 and 5, 100 µm for 3, 4 and 6.

FIGURES 14 – 17. Pachyseius spp., females. 14. Pachyseius siranensis sp. nov., sternal shield; 15. Pachyseius siranensis sp. nov., ventri-anal shield; 16. Pachyseius masani sp. nov., sternal shield; 17. Pachyseius masani sp. nov., ventri-anal shield.