Zygoseius papaver, Ahadiyat, Ali & Beaulieu, Frederic, 2016

Ahadiyat, Ali & Beaulieu, Frederic, 2016, Two new mite species of the genus Zygoseius Berlese from Mexico (Acari, Mesostigmata), ZooKeys 629, pp. 11-49 : 13-25

Taxon classification Animalia Mesostigmata Pachylaelapidae

Zygoseius papaver sp. n. Figures 1, 2, 3, 4, 5, 6, 7, 8, 9,, 10-13, 14, 27, 28, 29, 30, 31, Plate 1

Diagnosis

(female). Dorsal shield oval, well-reticulated throughout, except nearly smooth medially between setae j6-J4; shield with serrated lateral margins. Dorsal setae smooth, relatively short, all <35 long, some podonotal (s3-5, z6) and opisthonotal (J1, J2, J4, Z1-4) setae longer than other setae; setae J5 strongly mesad, and slightly anterad Z5. Sternal shield irregularly and sparsely micropunctate, with a transverse, recurved linea posterad level of setae st1. Epigynal shield punctate, mostly anteriorly and laterally. Ventrianal shield wider than long, lineate except anterad anus, and punctate except in anterior fourth; setae JV1-2 1.5 –2× as long as other setae on shield. Peritrematal shield micropunctate; punctae larger in poststigmatic region. Soft lateral and opisthogastric integument bearing nine pairs of short setae. Epistome bifurcate, distal haves of projections bipectinate. Hypostomal setae h1 twice as long as h2 and 1.5 × as long as h3. Cheliceral movable digit with two subapical, unconspicuous teeth. Cheliceral fixed digit with two subapical teeth. Genua II–III with 10 and 8 setae, lacking setae av and pv, respectively. Spermathecal apparatus with globular spermatheca separated from small, ring-like sperm reservoir by a thick-walled, short duct; spermatic canal long, narrow.

Description.

Female (n = 11). Dorsal idiosoma (Figs 1, 28). Dorsal shield ovoid, 340-374 long, 252-275 wide (length/width ratio: 1.26-1.44), completely covering idiosoma, slightly widened posteriorly. Shield margins serrated posterolaterally from level of setae r3. Shield well-reticulated throughout, except more or less smooth medially in j5-6 region and in median narrow band between setae j6-J4. Reticulations in opisthonotal region densely covered with small punctae. Posterior region between pairs of setae J4, Z4, J5 with large punctae, not reticulate. Dorsal shield bearing 37 pairs of setae, 23 and 14 pairs on podonotal and opisthonotal regions, respectively; setae J3 missing. Dorsal setae less than 35 long (Table 1), all smooth, acuminate, slightly widened in basal halves, except J5 pilose in basal half (Fig. 3A); setae J4 slightly pilose basally in some specimens (Fig. 3B). Dorsal idiosoma with 23 pairs of pore-like structures, including seven gland openings and 16 poroids.

Ventral idiosoma (Figs 2, 29). Tritosternum with a trapezoidal base 22-27 long, 11-13 wide proximally, 4-6 wide apically, and a pair of laciniae, 76-83 long; laciniae with barbs relatively short and blunt (Fig. 4). Sternal shield 93-105 long, 55-65 wide (length/width ratio: 1.50-1.78), bearing two pairs of poroids (iv1-2), and three pairs of smooth, subequal setae st1-3 (Table 1); anterolateral arms of shield each insens ibly fragmented apically into a platelet, itself abutting subtriangular exopodal plate between coxae I and II; shield anterior margin with a weak, wide median depression and two subtriangular projections; posterior margin narrow, truncate. Shield irregularly and sparsely micropuntate. A transverse, recurved linea posterad level of setae st1. Metasternal platelets fused to endopodal elements, arc-like in shape, punctate, bearing simple setae st4 and poroids iv3. Epigynal shield trapezoidal, 72-79 long, 22-27 long from st5 to posterior margin, 68-81 wide (length/width ratio: 0.91-1.03), with punctae most conspicuous in anterior and lateral portions; lineate posteriorly, three pairs of large subcircular sigillae centrally; anterior hyaline portion rounded, poorly sclerotized, indistinct; shield widest past level of st5, with posterior margin truncate; closely abutting ventrianal shield. Setae st5 smooth, inserted near shield lateral margins; poroids iv5 near posterolateral margins of shield. Ventrianal shield subpentagonal, expanded, wider than long, 113-121 long, 147-180 wide (length/width ratio: 0.70-0.80), straight anteriorly between setae ZV1. Shield distinctly lineate anteriorly, distinctly punctate posteriorly and medially, weakly lineate posterad JV2 level, with small punctae in lateral margins; shield with five pairs of pre-anal and three circum-anal setae, all smooth. Setae JV1-2 subequal, 1.5 –2× as long as other setae (Table 1); para-anal setae inserted near level of anterior margin of anal opening; gland openings gv3 on posterolateral margins of shield near mid-level of anus; cribrum well-developed, with a few narrow transversal strips of spicules; anal opening 20-25 long, 18-22 wide, subtriangular to ovoid, located in posterior fourth or third of shield. Peritreme 175-198 long, densely covered by aciculae, extending anteriorly almost to level of seta z1, with one gland pore (gp) located at mid-level of coxa II. Peritrematal shield wide, essentially in ventral position; completely fused to exopodal, parapodal and metapodal elements, extending well behind posterior level of coxae IV. Shield essentially micropunctate throughout, with larger punctae in poststigmatic region, bearing four pore-like structures (id3, gd3, id7), including gv2. Exopodal element between coxae II–III insensibly separated from posterior portion of more posterior exopodal-peritrematal elements (Fig. 5). Soft lateral and opisthogastric integument finely plicate, bearing nine pairs of short smooth setae, 11-20 long, most of which slightly thickened basally; soft cuticle with five pairs of poroids (4 ivo, idR3), and one subcircular platelet bearing two pore-like structures (putatively a gland pore, and an associated poroid), near posterolateral margin of peritrematal-metapodal shield.

Gnathosoma. Epistome (Fig. 6) bifurcate, with two long (12-20) and relatively thick projections, forming a U-shape at their bases (separated by 4-7); distal halves of projections deeply serrated on both inner and outer margins, margins proximally smooth; basal margins coarsely serrated laterally. Posteromedian ridge with denticles in lateral portions; larger denticles or tubercles on posterolateral ridges. Corniculi (Fig. 7) 28-31 long, horn-like. Internal malae (Fig. 7) with a pair of smooth lobes, apically blunt, membranous, almost reaching apex of corniculi; labrum longer than internal malae, fimbriate distally. Hypostomal and capitular setae (Fig. 7) smooth, needle-like, h1 (39-45)>h3 (24-31)>pc (17-24)≈h2 (17-21). Deutosternum (Fig. 7) with seven transverse rows of denticles; rows broad, variable in width, 5th and 7th, or 5-7th rows usually broader, anteriormost (first) row with larger denticles; numbers of teeth in rows from anterior row (1st) to posterior row (7th), respectively: 7-9, 12, 10-12, 13-14, 14-15, 13-15, 13-15. Chelicera (Fig. 8) with movable digit with two subapical, inconspicuous teeth; fixed digit with two subapical teeth followed by a short, relatively thick pilus dentilis; dorsal cheliceral seta short, setiform; first cheliceral segment 34-55 long, second 103-110 (17-28 wide), fixed digit 29-33, movable digit 34-40. Palp (Fig. 9) 101-107 long, with dorsal surfaces of genu and especially femur with some sigillae; trochanter 11-14 long, femur 31-37, genu 27-30, tibia 19-22; apotele 3-tined. Palp chaetotaxy: from trochanter–tibia 2-5-6-14 setae; trochanter 0 0/1 0/1 0, femur 1 2/0 1/0 1, genu 2 2/0 1/0 1 and tibia as in Fig. 9; all palp setae smooth, tapered; av (v2, sensu Evans 1963b) on trochanter strongly bent inwards (Fig. 27); al on femur, al1-2 on genu and one of al setae on tibia short and spatulate; genu with stout spur dorsodistally (see arrow, Fig. 9).

Legs (Figs 10-13). Lengths of legs: I 265-305, II 253-279, III 234-250, IV 271-300. Lengths of femora: I 56-64, II 42-58, III 45-53, IV 58-68; genua: I 45-49, II 36-41, III 25-30, IV 27-32; tibiae: I 40-46, II 29-36, III 27-29, IV 30-36; tarsi: I 57-65, II 73-85, III 67-73, IV 82-95; ambulacra: I 20-23, II 20-24, III 19-22, IV 22 -25. Chaetotaxy of leg segments I–IV normal for Zygoseius (sensu Halliday 1997) except for genu II and genu III: coxae 2-2-2-1, or I–III (0 0/1 0/1 0), IV (0 0/1 0/0 0); trochanters 6-5-5-5, or I (1 0/1 1/2 1), II (1 0/1 0/2 1), III–IV (1 1/1 0/2 0); femora 13-11-6-6, or I (2 3/1 2/3 2), II (2 3/1 2/2 1), III–IV (1 2/1 1/0 1); genua 13-10-8-9, or I (2 3/2 3/1 2), II (2 3/0 2/1 2), III (2 2/1 2/0 1), IV (2 2/1 3/0 1); tibiae 13-10-8-8, or I (2 3/2 3/1 2 in 10 females or 2 4/2 3/1 2 in one of the 11 females), II (2 2/1 2/1 2), III–IV (2 1/1 2/1 1); tarsi II–IV 18-18-18, all as 3 3/2 3/2 3 + md and mv. All setae on legs I–IV simple, relatively short and tapered, except: femur I with pd1-2 thickened (lengths: pd1 12-13, pd2 10-11); tarsi II–IV with apical setae al1, av1, pv1, pl1 and subapical setae av2, pv2, md and mv short, spur-like. Trochanter III with small cuticular spur posterolaterally, and trochanter IV with two cuticular spurs, posterolaterally and posterodorsally. Sigillae on ventral surfaces of coxae I–IV and trochanters I–II, and dorsal surfaces of femora, genua and tibiae I–IV, and basitarsi II–IV. All ambulacra with a pair of well-developed hooked claws. Pulvilli not discerned.

Spermathecal apparatus (Plate 1). Spermatheca (Plate 1C) globular, large (diameter 8-11), connected to a short, thick-walled duct (5-10 long), followed by a small ring-like sperm reservoir (diameter 5-6), and a narrow and long spermatic canal (16-24 long), sometimes widened basally (as in Plate 1B).

Male (n = 1). Dorsal idiosoma (Fig. 30). Dorsal shield oval, 338 long, 252 wide (length/width ratio: 1.34), completely covering idiosoma. Shield ornamentation and chaetotaxy similar to those of female, except reticulation in central region of idiosoma between setae j6-j6 to J2-J2 more distinct.

Ventral idiosoma (Fig. 31). Tritosternum as in female, 14 long, 11 wide proximally, 6 wide apically; laciniae 76 long. Gonopore diameter 20, discernible part of duct 50 long. Holoventral shield 271 long, 217 wide (length/width ratio: 1.25), reticulate nearly throughout except between setae st5-JV1, cells punctate inside and along margins; ventral region weakly lineate and punctate between setae JV1 and JV2, with more distinct punctae laterally and especially posteriorly. Holoventral shield fused laterally to peritrematal, metapodal and exopodal elements, bearing 12 pairs of simple and smooth setae (five and seven pairs on sternogenital and ventrianal regions, respectively) (Table 1), and three smooth circum-anal setae; shield with nine pairs of pore-like structures (iv1-3, iv5, gv2-3, three pairs of ivo), excluding those on peritrematal-exopodal shields. Setae JV1-2 longer than other ventral setae, including JV3-5, ZV1-3 (Table 1). Peritreme 178 long. Soft lateral and opisthogastric integument with 6-7 pairs of short setae, 7-15 long, slightly thickened basally, and two or three pairs of pore-like structures. Anal opening subtriangular, 22 long and 19 wide. Other features of ventral idiosoma as in female.

Gnathosoma. Epistome as in female, with two projections, 19 long, distance between bases of projections 5. Corniculi (26 long) and deutosternum as in female. Lengths of hypostomal setae: h1 39, h2 14, h3 24, pc 19. Chelicera and spermatodactyl not avail able for study (broken off specimen). Palp 98 long, similar to that of female; trochanter 13 long, femur 40, genu 22, tibia about 21; palp setae and chaetotaxy as in female.

Legs. Lengths of legs: I 288, II 239, III 231, IV 288. Lengths of femora: I 61, II 44, III 55, IV 60; genua: I 45, II 37, III 26, IV 30; tibiae: I 44, II 32, III 25, IV 31; tarsi: I 61, II 71, III 68, IV 87, ambulacra: I 18, II 20, III 19, IV 24. Chaetotaxy of legs I–IV similar to that of female, except that the femur II has one conical spine-like projection ventrodistally (Fig. 14). Setae pd1-2 on femur I thickened as in female, pd1 14-15, pd2 10-12. Sigillae locations similar to those of female.

Immature stages.

Unknown.

Material examined.

Holotype: Female. Mexico, Chiapas State, Volcan Tzontehuitz, 9000 ft. (= 2743.2 m. a.s.l.), 12 miles NE of San Cristóbal de Las Casas, from moss on log, 19 May 1969, coll. J. M. Campbell. Paratypes: 15 females, 1 male, same data as holotype. The holotype and 12 paratypes (females and male) are deposited at the Canadian National Collection of Insects, Arachnids and Nematodes (CNC) at the Agriculture and Agri-Food Canada, Ottawa, Canada, and four female paratypes are deposited at the Acarology Collection of the Department of Entomology(ACDE), College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Tehran, Iran.

Etymology.

The specific name refers to the shape of the spermatheca of the new species, which resembles the capsule of opium ( Papaver somniferum L., 1753). It is considered as a noun in apposition.

Remarks.

The spermathecal apparatus of Zygoseius papaver sp. n. is distinct from that of any other Zygoseius species for which it was described: the spermetheca is globular and larger than any other sclerotized part of the apparatus, and ends in a flower-like pattern. The new species can also be distinguished by its long J1-2 setae relative to the distance between J1 and J2 setae (ratio setal length/distance = 0.90 ± 0.06 st.dev., range 0.75-1.0). Based on their illustrations, a few species described from South America have long J1-2 setae relative to the distance between them, such as Zygoseius alveolaris Karg, 1998 and Zygoseius triramuli Karg & Schorlemmer, 2009 ( Karg 1998, Karg and Schorlemmer 2009), but these have a different arrangement of setae of the j–J series, including the presence of J3.

The epistome of Zygoseius papaver sp. n. is unique among described species, with relatively short but thick projections that are conspicuously barbed apically. The epistome of Zygoseius laticuspidis Karg, 1998 is similar; however, it is even more swollen apically, and is slightly denticulate on the basal margin in-between the projections. Zygoseius laticuspidis also has J5 setae inserted mesad of Z5 (note, however, that the relative position of J5 and Z5 can vary, depending on how flattened is the dorsal shield on the slide). The new species can further be distinguished from Zygoseius laticuspidis by its shorter dorsal setae (all are <30 long; most are 30-60 long in Zygoseius laticuspidis ), J4 setae separated by 1.4 –1.9× the distance between J1 setae (J4-J4 distance over twice that between J1-J1 in Zygoseius laticuspidis ), and by the presence of nine pairs of setae on the opisthogastric soft cuticle (six pairs in Zygoseius laticuspidis ). Other Zygoseius species can be distinguished from Zygoseius papaver sp. n. by some of the same characters mentioned above, as well as by (1) its epistome; (2) the length and width (and their ratios) of the dorsal, sternal and ventrianal shields; (3) relative length of dorsal setae, especially Z5; (4) the ornamentation of the dorsal and sternal shields; and (5) long JV1-2 setae, 1.5 –2× as long as other pre-anal setae on the ventrianal shield, and as long as about 2/3 of distance between JV1 and JV2. Zygoseius ampullus Halliday, 1997 and Zygoseius foramenis Karg, 1998 also have longer JV1-2 setae but clearly differ by their epistomes, and by shorter J1-2 setae and a ventrianal shield as long as wide. In the key to species of Karg and Schorlemmer (2009), Zygoseius papaver sp. n. would reach couplet 3 (12), and can be distinguished from species in (3) and (12) by the characters mentioned above.

Another distinguishing feature of Zygoseius papaver sp. n. is the distinctly serrated lateral margins of the dorsal shield. This also characterizes Zygoseius ovatus Karg, 1998. The margins of the dorsal shield of other species may appear somewhat serrated (e.g. Zygoseius ampullus , Zygoseius metoecus Halliday, 1997 and Zygoseius separatoporus Karg, 1998), although the serration matches with the insertion of setae in marginal positions (mostly r and S setae), whereas in the new species and at least in Zygoseius ovatus , most serration are independent of setal insertions. Such serrated margins of the dorsal shield are reminiscent of the dorsal shield of many Zerconidae ( Ujvári 2010, 2011) and some species of Pachyseius Berlese ( Pachylaelapidae ) ( Mašán 2007, Ahadiyat et al. 2016). Note that the serration of dorsal shields in zerconid and Pachyseius species is largely correlated, although not entirely, with the insertion of marginal setae.

Zygoseius papaver sp. n. also differs from other Zygoseius species by its reduced chaetotaxy on genu II, lacking seta av, and genu III, lacking seta pv, instead of the usual complement of two ventral setae, including both av and pv as noted in the genus diagnosis of Halliday (1997). His diagnosis was based on four species ( Zygoseius furciger , Zygoseius ampullus , Zygoseius metoecus , Zygoseius sarcinulus ), so we can predict that other described (with unstudied leg chaetotaxy) and undescribed species have such genual chaetotaxy. However, because at least another species of Zygoseius , newly described herein (see below), sometimes lacks pv on genu III, we can suspect that other species also lacks such seta. Members of other non-parasitic dermanyssine families lack both of these setae (e.g. Phytoseiidae ; Evans 1963a), or lacks either av on genu II (some Pseudolaelaps species, Pseudolaelapidae; Mašán 2014) or more commonly pv on genu III (e.g. some Eviphididae , Pachylaelapidae , Macrochelidae , Ascoidea, Blattisociidae ; Evans 1963a, Lindquist and Evans 1965, Moraza and Johnston 1990, Mašán 2007, Mašán and Halliday 2010), showing plasticity of the development of those setae. Based on the studied chaetotaxy of Zygoseius furciger and of other dermanyssines ( Evans and Till 1965, Lindquist and Evans 1965, Halliday 1997), when present in the adults, ventral setae of genua II–III appear at the deutonymphal stage. Therefore, they are theoretically not as stable as (i.e. less likely to be retained in the adult stage than) setae appearing at an earlier developmental stage ( Evans 1963a, Lindquist and Evans 1965, Rowell et al. 1978).