Scutacarus ellipticus Karafiat, 1959

Jagersbacher-Baumann, Julia & Ebermann, Ernst, 2016, Support for the underrepresented sex: new descriptions of scutacarid males (Acari, Heterostigmatina), Zootaxa 4179 (3), pp. 371-409 : 390-393

Scutacarus ellipticus Karafiat, 1959

( Figs. 1 , 3 , 14 , 15 )

MALE. Idiosoma length 120–160, n = 10.

Gnathosoma ( Fig. 1 f) extended, tube-shaped. One pair of finger-shaped solenidia, two pairs of dorsal setae ch 1 and ch 2 and one ventral pair of ventral setae su, thin, smooth, su slightly longer than ch 1 and ch 2. One pair of short tube-like accessory setigenous structures distally.

Dorsum ( Fig. 14 a). Idiosoma with four sclerotized, finely dotted plates. Most posterior plate forms dorsal cover for genital capsule. Length of dorsal setae: v about 7, sc 1 7, sc 2 24, c 1 23, c 2 22, d 23, e 8, f 32, h 1 6. Setae v, sc 1, e smooth, sc 2, c 1, c 2, d, f distally strongly barbed, all setae blunt-ended. h 1 and h 2 smooth, blunt-ended, h 2 minute. Distance between dorsal setae: v–v about 6, sc 1 –sc 1 27, sc 2 –sc 2 20, c 1 –c 1 27, c 2 –c 2 63, d–d 51, e–e 36, f–f 20, h 1 –h 1 22, h 2 –h 2 21.

Genital apparatus ( Figs. 3 f, 14a). Segments H and PS fused, form genital capsule. Length of genital plate (tergite H) about 45. Posterior edge of plate narrowed, ratio length: width of genital plate = 1: 0.49. Area posterior of h 1 with roundish, sucker-like structures or cavities. Aedeagus like in I. dispar .

Venter ( Fig. 14 b). Sternal plates finely dotted. Ap1 weakly sclerotized, prosternal ap continuous from ap1 to sejugal ap; ap2, sejugal ap, ap3, and ap4 complete, weakly sclerotized; ap5 strongly sclerotized; poststernal ap between ap 3I and ap5 complete, strongly sclerotized. Length of ventral setae: 1 a about 9, 1 b 10, 2 a 9, 2 b 10, 3 a 9, 3 b 9, 3 c 9, 4 a 7, 4 b 9, 4 c 8, ps 1 5, ps 2 9. All setae smooth, short, pointed. Distance between ventral setae: 1 a –1 a about 10, 1 b –1 b 36, 2 a –2 a 19, 2 b –2 b 36, 3 a –3 a 20, 3 b –3 b 35, 3 c –3 c 55, 4 a –4 a 22, 4 b –4 b 5, 4 c –4 c 47, ps 1 –ps 1 17, ps 2 –ps 2 19.

Leg I ( Fig. 15 a). Setal formula: Tr1–Fe3–Ge4–Ti6(2)–Ta13(2). Ta with one small, padded claw. Sol ω2 thick, sol ω1 thin, both finger-shaped, sol ϕ1 club-shaped, sol ϕ2 finger-shaped. Length of solenidia: ω1 about 10, ω2 21, ϕ1 6, ϕ2 8. Setae pl’, pv’’, l’Ti and l’’Ge sparsely barbed, all other setae smooth; all setae pointed. Eupathidia tc’ and tc’ ’ situated on a low process.

Leg II ( Fig. 15 b). Setal formula: Tr1–Fe3–Ge3–Ti4(1)–Ta7(1). Ta with two small claws and empodium. Sol ω thick, finger-shaped, ϕ club-shaped, ω 15, ϕ 5. Setae pv’, pl’’, v’Ti, v ’’ Ti and l’Ge sparsely barbed, all other setae smooth, all setae pointed.

Leg III ( Fig. 15 c). Setal formula: Tr1–Fe2–Ge2–Ti4(1)–Ta7. Ta with two small claws and empodium. Sol ϕ 5, finger-shaped. Eupathidia tc’ and tc’’, setae u’, u’’, pv’’, dTi and l’Fe smooth, all other setae sparsely barbed; all setae pointed.

Leg IV ( Fig. 15 d, Table 1 ). Setal formula: Tr1–Fe1–Ge1–Ti4(1)–Ta6. Distal Ta with two adhesive pads of differing size. Tarsal setae tc’, tc’’ are longest, length tc’ about 54, tc’’ 29. Seta v’’Ti and pv’’ spine-like, smooth, v’’Ti> pv’’, pl’’ hook-like, smooth. Setae tc’, tc’’, v’Ti and dGe sparsely barbed, other setae smooth. Seta u small, sol ϕ 8, thin, finger-shaped. Small broad spine proximal to solenidion.

Differential diagnosis. Males of S. ellipticus can be differentiated from Archidispus , Heterodispus and Imparipes by the presence of accessory setigenous structures on the gnathosoma. Amongst the remaining known males, S. ellipticus is unique because of the dorsal setae sc 2, c 1, c 2, d and f, which are strongly barbed distally. Material examined. 10 males from laboratory cultures based on females from soil; AUSTRIA: Dobl, 46°56'56.8"N, 15°22'26.2"E, 1985, leg. Ebermann.

Deposition of material. 2 males: Natural History Museum Vienna, Austria ( NHMW 27.643 ) ; 6 males: Institute of Zoology , University of Graz, Austria ; 2 males: Museum of Natural History of the City of Geneva, Switzerland .

Figures

FIGURE 1. Dorsal view of the male gnathosoma: a. Heterodispus foveatus, b. Imparipes dispar, c. Lamnacarus ornatus, d. Scutacarus acarorum, e. S. deserticolus, f. S. ellipticus, g. S. longipes, h. S. longitarsus, i. S. tackei, j. S. tyrrhenicus. Abbreviations: ass = accessory setigenous structures.

FIGURE 3. Dorsal view of the genital plates of: a. Heterodispus foveatus, b. Imparipes dispar, c. Lamnacarus ornatus, d. Scutacarus acarorum, e. S. deserticolus, f. S. ellipticus, g. S. longipes, h. S. longitarsus, i. S. tackei, j. S. tyrrhenicus large male (idiosoma length 200 µm), k. S. tyrrhenicus small male (idiosoma length 140 µm).

FIGURE 14. Scutacarus ellipticus male: a. dorsal view, b. ventral view.

FIGURE 15. Scutacarus ellipticus male: a. leg I, b. leg II, c. leg III, d. leg IV.