Novophytoptus maritimus, Chetverikov, Philipp E., 2015

Chetverikov, Philipp E., 2015, Hidden diversity of endoparasitic eriophyoid mites: two new Novophytoptus Roivainen, 1947 (Acari: Eriophyoidea: Phytoptidae) species from the parenchymatous tissues of rushes (Juncaceae), Zootaxa 4006 (3), pp. 481-505 : 494-497

Novophytoptus maritimus n. sp.

( Figs. 5 J–R, 10, 11, 12)

Female (n=9: holotype & paratypes). Idiosoma vermiform, 312 (275–339), 43 (49–47) wide at level of setae c2, 49 (44–55) wide at level of setae f. Prodorsal shield ( Figs. 5 J–R, 10) subpentagonal, 31 (28–35) x 21 (18–22) wide, with two ocella-like spots lateral to setae ve. Anterior margin of prodorsal shield acuminate, forming a short triangular lobe. Shield ornamentation with complete entire median line and admedian lines from rear to anterior shield margin. In posterior half of shield, admedian lines curved, forming a bulb-shaped figure. Two thin, submedian-1 lines running parallel to admedian lines in anterior half of shield with five distinct thin lines seen in well-mounted specimens, usually parallel and not convergent; several additional indistinct longitudinal wrinkles or ridges sometimes seen lateral to the five median lines; two or three thin lines present between tubercles ve and anterior “bottle”. Rudimentary medioposterior fovea (“pit” sensu Keifer) surrounded by small scattered lines present on rear prodorsal shield margin. Area between tubercles of sc smooth; a group of about 30–35 circular/oval granules anteriorly to each sc tubercle. Setae ve 15 (12–16), directed anterolaterad, tubercles 10 (9–12) apart; sc 74 (68–84), directed posterolaterad, tubercles 15 (15–19) apart. Distance between tubercles ve–sc 20 (17–23). Gnathosoma elongate, directed forward and slightly ventrad, 31 (31–38); pedipalp coxal seta ep 4 (3–6), pedipalp genual seta d absent, subapical pedipalp tarsal seta ν 0.5 (0.5–1). Basal gnathosoma covered by seemingly smooth suboral plate.

Leg I 36 (34–40), tibia 12 (10–14), l' 6 (5–7), tarsus 5 (5–6), u ′ 2 (1–2), ft ′ 3 (3–3), ft″ 14 (14–18); ω 5 (5–7), without knob; empodium 4/4-rayed, 7 (6–8), each ray of the three basal pairs with one or two tiny secondary branches, terminal paired rays without additional branching, of equal length, situated on rod-like shaft, thus remote from other rays ( Figs. 5 O, 11B). Leg II 32 (31–35), tibia 8 (8–9), tarsus 4 (4–6), u 1 (1–2), ft ′ 2 (2–5), ft″ 23 (21– 24); ω 11 (9–13), without knob; empodium 4/4-rayed, 9 (9–10), each ray of the three basal pairs with one or two tiny secondary branches, terminal paired rays without additional branching, internal terminal ray 5–7 times longer than external ray ( Figs. 5 Q, 11B).

Coxae ornamented with several lines. Prosternal apodeme faint, inversely T-shaped, extending from rear margin of suboral plate to past level of 1a tubercles. Setae 1b 15 (10–19), 12 (11–13) apart; 1a 35 (25–38), 7 (6–8) apart; 2a 50 (33–60), 20 (18–23) apart; 12 (12–16) complete and 1 (1–2) incomplete (i.e. segregated from lateral annuli) coxigenital annuli before epigynium. Genital coverflap semi-circular, smooth, 9 (8–10) x 16 (15–18) wide; setae 3a notably thickened, 12 (11–15), 14 (14–18) apart.

Opisthosoma vermiform (nearly parallel-sided for most of length), slightly expanded caudally: widest at level of f tubercles; dorsal and ventral annuli bearing small, elongated microtubercles, last 6 (5–7) dorsal annuli without microtubercles. Setal lengths: c2 29 (23–29), d 18 (17–25), e 14 (12–15), f 14 (14–18), h1 7 (5–9), h2 87 (80–115); 10 (10–13) annuli from rear shield margin to c2; 15 (12–17) annuli between c2–d; 17 (16–20) annuli between d and e; 31 (28–36) annuli between e and f; 7 (6–7) annuli between f and h1. Opisthosomal setae c2, d, e and f notably thickened ( Fig. 12 A, B).

Remarks. One aberrant female of N. maritimus n. sp. (slide #u1/3-12) had a shortened and expanded tarsus on Leg I, which was fused with the tibia ( Fig. 11 C,D). The tarsal solenidion ω I was displaced medially and seta ft ′ I was shortened and thickened. It appears that mutants (Figs. 8; 11 C,D) are common in populations of novophytoptines. This may be the result of inbreeding within the mite colonies which are isolated under the epidermis.

Male. Only one male specimen in good condition was available for measurement. In comparison to females, this male was wider (at the level of tubercules c2 and f); had shorter setae sc, 1a, 2a, h2; with tarsal solenidia ω I, II, opisthosomal setae c2, d, e and f of common thickness ( Fig. 12 C); with more annuli (45) between tubercules e and f ( Table 1 ). The external genitalia were cone-shaped, with two posterior flaps and anterior papilla-like protuberance (translucent in slidemounts) and eugenital setae seemingly absent ( Fig. 12 C). Remarkably, rather short em I, II (about 3 µm) with all rays of equal length were observed ( Fig. 5 N). In females, these are much longer (7 and 10 µm respectively) and have one or two elongated terminal rays ( Fig. 5 O,Q).

Host plant. Juncus maritimus Lam. (sea rush): distributed in Azores, Europe to Central Asia ( Govaerts 2014)

Relation to host. Mites live in air cavities of parenchymatous tissues (aerenchyma) inside the stems.

Type material. Female holotype (encircled by black marker) on slidemount #u1/2-12. Paratypes: 18 specimens (nine females, four males and five immatures) on slidemounts #u1/1-12, #u1/2-12 and #u1/3-12. All specimens from UKRAINE: Zaporozhye Prov., Kirillovka, 46°18′32″N, 35°18′30″E, 16 September 2012, coll. T.G. Chetverikova.

Etymology. The specific epithet, maritimus , is a masculine singular adjective corresponding to the specific name of the host-plant.

Differential diagnosis. The new species is close to N. luzulis n. sp. (described above). Females of these two species differ in the length of the gnathosoma (longer in N. maritimus ), length of sc (shorter in N. maritimus ), length of ω II and em II (longer in N. maritimus ), thickness of setae c2, d, e and f (notably thicker in N. maritimus ), number of dorsal and ventral annuli (both more numerous in N. maritimus ), prodorsal shield ornamentation and shape of terminal rays of empodia I and II ( Table 4 ).

Character Mite species

Figures

FIGURE 5. Schematic drawings of Novophytoptus luzulis n. sp. (A – I) and Novophytoptus maritimus n. sp. (J – R): prodorsal shields (A, M), antero-ventral part of body (B, J); legs I (D, K); legs II (C, L); empodia I (E, O); empodia II (G, Q); tarsal solenidia I (F, P); tarsal solenidia II (H, R); male empodia I (I, N). Note: all images except I and N represent females. Scale bar: A, M = 15; B, J = 25; С, D, K, L = 15; E – H and N – R = 10.

FIGURE 11. DIC images of legs and tarsal appendages of normal (A, B) and aberrant (C, D) females of Novophytoptus maritimus n. sp. А — dorsal view of leg I and II on the level of ω I and II in focus; B — empodia I and II (same mite as on Fig. A); C, D — aberrant tarsus I, with ω I displaced medially and seta ft’ short and stout. Note: on Fig. C tarsus is coloured in red and tibia is coloured in green. Scale bar: A = 15 Μm; B = 10 Μm; C, D = 5 Μm.

FIGURE 12. DIC images of genital region of Novophytoptus maritimus n. sp. showing difference in the thickness of opisthosomal setae in females (A, B) and males (C). Scale bar = 15 Μm.