Dolichotetranychus summersi Pritchard & Baker, 1952

Stathakis, Theodoros I., Vrettos, Dimitrios P., Panou, Eleni N. & Kapaxidi, Eleftheria V., 2023, New recordsof falsespider mites (Acari: Trombidiformes: Tenuipalpidae) in Greece, Zootaxa 5230 (4), pp. 456-466 : 461-465

Dolichotetranychus summersi Pritchard & Baker, 1952

( Figs. 4–8 )

Dolichotetranychus summersi Pritchard & Baker (1952) : 45.

Dolichotetranychus (Dolichotetranychoides) summersi: Mitrofanov & Strunkova 1979: 116

Material examined. 8 females ex leaf litter beneath unidentified Poaceae , Greece, Co. Elia, Kaiafas Lake (37°30′42.2″N, 21°35′59.2″E), 27 October 2012, coll. T.I. Stathakis; 3 females and 2 deutonymphs ex Elymus repens (L.) Gould ( Poaceae ), Greece, Kea Island, Stavroudaki (37°34′13.2″N, 24°19′09.4″E), 26 July 2020, coll. D.P. Vrettos.

Description. FEMALE (n = 10). Dorsum ( Fig. 4A , 6A, B ). Body size measurements: distance between setae v 2 – h 1 240–260; sc 2 – sc 2 135–150; other measurements: v 2 – v 2 46–51, sc 1 – sc 1 110–120, c 1 – c 1 18–28, c 2 – c 2 120–140, c 3 – c 3 140–165, d 1 – d 1 28–36, d 3 – d 3 59–87, e 3 – e 3 55 – 61, f 3 – f 3 50 – 55, h 1 – h 1 14 – 18, h 2 – h 2 36 – 38. Propodosoma anterior to setae v 2 with irregular, transverse, broken lobed striae. Propodosomal striae posterior to setae v 2 mostly longitudinal; some of them oblique posteromedially, becoming posteriorly transverse and lobed. Propodosoma and opisthosoma divided by area of almost transverse, broken lobed striae. Opisthosoma with longitudinal to oblique striae posterior to setae c 1; these striae in medial area lobed. All dorsal setae short, slender, smooth or with few minute barbs; setae f 3, h 1-2 more conspicuously barbed and slightly longer than other setae. Length of setae: v 2 12 – 18, sc 1 20 – 24, sc 2 18 – 22, c 1 6 – 8, c 2 20 – 24, c 3 18 – 24, d 1 6, d 3 14 – 18, e 3 12 – 16, f 3 16 – 24, h 1 20, h 2 24 – 28.

Venter ( Figs 4B , 6C, D ). Intercoxal region I–II with smooth longitudinal striae, becoming lobed and transverse posterior to coxa II and to level of setae 3a; striae between setae 3a and ag longitudinal and lobed. Genital plate weakly developed with a single pair of genital setae g inserted on its posterior margin. Pseudanal setae ps 1 – 2 inserted on weakly defined anal plates. Coxal, genital and pseudanal setae smooth. Length of setae: 1a 65–69, 1b 12–15, 1c 8–10, 2c 12, 3a 50–58, 3b 7–9, 4a 12–13, 4b 6–12, ag 5–7, g 8–9, ps 1 4–5, ps 2 4–5. Spermathecal duct narrow, nearly straight. Spermathecal vesicle elongate, 8 long ( Fig. 4D ).

Gnathosoma ( Fig. 4E ). Rostrum exceeding beyond distal end of femur I. Subcapitular setae m absent. Palps 3-segmented 12–14 in length. Setal formula 0-1-2(1), solenidion ω 5–6 long.

Legs ( Figs 5A–C ). Setal formula for legs I–IV (coxae to tarsi) 2-1-4-2-4-9(1), 1-1-4-1-4-9(1), 1-2-2-0-3-5, 1-0- 1-0-3-5, respectively. Tarsi I, II, each with one abaxial solenidion, ω′′I 5–6, ω′′II 5–6 long. Dorsal setae on femora and genua slender and barbed.

DEUTONYMPH (n = 2). Dorsum ( Fig. 7A ). Body size measurements: distance between setae v 2 – h 1 220; sc 2 – sc 2 130; other measurements: v 2 – v 2 44, sc 1 – sc 1 105, c 1 – c 1 20, c 2 – c 2 120–125, c 3 – c 3 140–145, d 1 – d 1 22–26, d 3 – d 3 63, e 3 – e 3 40 – 42, f 3 – f 3 38 – 40, h 1 – h 1 10 – 12, h 2 – h 2 26 – 28. Propodosomal striation similar to female; opisthosoma with transverse lobed striae medially, becoming irregular and sparse posteriorly. All dorsal setae short, slender, barbed. Length of seate: v 2 14, sc 1 16, sc 2 18 – 20, c 1 6, c 2 16, c 3 18, d 1 6, d 3 14, e 3 12 – 14, f 3 16, h 1 14 – 16, h 2 18 – 20.

Venter ( Fig. 7B ). Propodosomal and opisthosomal striation similar to female. Length of seate: 1a 50 – 54, 1b 12 – 15, 1c 8, 2c 8, 3a 42–46, 3b 6–7, 4a 9–10, 4b 5–6, ag 5, g 4–5, ps 1 3–4, ps 2 3–4.

Gnathosoma . Similar to female. Palps 10 in length; tibiotarsal solenidion ω 5 long.

Legs ( Figs 8A–C ). Setal formula for legs I–IV (coxae to tarsi) 2-1-3-1-4-9(1), 1-1-3-0-4-9(1), 1-1-2-0-3-5, 1-0- 1-0-3-5, respectively. Tarsi I, II, each with one abaxial solenidion, ω′′I 5, ω′′II 5 long.

MALE, PROTONYMPH and LARVA. Not found.

Remarks. Dolichotetranychus summersi Pritchard & Baker is characterized by a unique combination of morphological features: subcapitular setae m are absent; coxal setae 2b are absent; two pairs of anal and one pair of genital setae are present ( summersi species group). Morphological features of the specimens from Greece are very close to those in the original description and the redescription of paratypes provided by Seeman et al. (2016), except for little differences in specimens described herein: (a) the cuticle anterior to setae v 2 is more extensively dotted, and (b) the genital plate is less extensively striated. These differences are minor and should be considered intraspecific variations.

This species was formerly known only from adult stages collected in the USA (California and Arizona) and its only known host plant was the Bermuda grass, Cynodon dactylon (L.) Pers. ( Poaceae ) ( Pritchard & Baker 1952; Baker & Pritchard 1956; Pritchard & Baker 1958; Baker & Tuttle 1964). This is the first record of D. summersi in the Palearctic region and from a different host plant. The discovery of this species in two different locations in Greece and certainly in natural ecosystems extends its native range from the Nearctic at least to the Eastern Mediterranean in the Palearctic region. Elymus repens , a common perennial weed of the northern hemisphere, should be considered as a natural host plant for D. summersi due to the discovery of immatures (deutonymphs). The question about its potential as a pest species of commercial turfgrass C. dactylon still remains, until more collection data are available.

Figures

FIGURE 4. Dolichotetranychus summersi Pritchard & Baker, female. A—dorsal view, B—ventral view, C—anogenital area, D—spermatheca, E—gnathosoma. Scale bars: 50 μm (A, C), 20 μm (B, D, E).

FIGURE 5. Dolichotetranychus summersi Pritchard & Baker, female. A—leg I, B—leg II, C—leg III, D—leg IV. Scale bar: 20 μm.

FIGURE 6. Dolichotetranychus summersi Pritchard & Baker, female.A—propodosoma (dorsal view), B—opisthosoma (dorsal view), C—propodosoma (ventral view), D—opisthosoma (ventral view). Scale bar: 50 μm.

FIGURE 7. Dolichotetranychus summersi Pritchard & Baker, deutonymph. A—opisthosoma (dorsal view), B—opisthosoma (ventral view). Scale bar: 30 μm.

FIGURE 8. Dolichotetranychus summersi Pritchard & Baker, deutonymph. A—leg I, B—leg II, C—leg III, D—leg IV. Scale bar: 20 μm.