Scutacarus longipes Rack, 1975

Jagersbacher-Baumann, Julia & Ebermann, Ernst, 2016, Support for the underrepresented sex: new descriptions of scutacarid males (Acari, Heterostigmatina), Zootaxa 4179 (3), pp. 371-409 : 393-394

Scutacarus longipes Rack, 1975

( Figs. 1 , 3 , 16 , 17 )

MALE. Idiosoma length 120–130, n = 4.

Gnathosoma ( Fig. 1 g) 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, ch 1 shorter than ch 2 and su. One pair of short tube-like accessory setigenous structures distally.

Dorsum ( Fig. 16 a). Idiosoma with four sclerotized, finely dotted plates. Most posterior plate forms dorsal cover for genital capsule. Length of dorsal setae: v about 8, sc 1 7, sc 2 28, c 1 19, c 2 25, d 26, e 37, f 45, h 1 8. Setae v, sc 1 smooth, pointed, sc 2, c 1, c 2, d, e, f sparsely barbed, blunt-ended. h 1 and h 2 smooth, blunt-ended, h 2 minute. Distance between dorsal setae: v–v about 4, sc 1 –sc 1 15, sc 2 –sc 2 19, c 1 –c 1 31, c 2 –c 2 61, d–d 48, e–e 42, f–f 16, h 1 –h 1 21, h 2 –h 2 21.

Genital apparatus ( Figs. 3 g, 16a). Segments H and PS fused, form genital capsule. Length of genital plate (tergite H) about 47. Posterior edge of plate narrowed, ratio length: width of genital plate = 1: 0.44. Area posterior of h 1 soft-skinned, no sucker-like structures or cavities recognisable in microscopic slides. Aedeagus like in I. dispar .

Venter ( Fig. 16 b). Sternal plates finely dotted. Ap1 weakly sclerotized, prosternal ap continuous from ap1 to sejugal ap; ap2 complete, strongly sclerotized; sejugal ap, ap3, ap4 and ap5 complete, weakly sclerotized; poststernal ap between ap3 and ap5 complete, clearly sclerotized. Length of ventral setae: 1 a about 10, 1 b 8, 2 a 8, 2 b 9, 3 a 10, 3 b 9, 3 c 9, 4 a 8, 4 b 9, 4 c 8, ps 1 2, ps 2 4. All setae smooth, short, pointed. Distance between ventral setae: 1 a –1 a about 11, 1 b –1 b 31, 2 a –2 a 16, 2 b –2 b 33, 3 a –3 a 16, 3 b –3 b 27, 3 c –3 c 46, 4 a –4 a 18, 4 b –4 b 5, 4 c –4 c 38, ps 1 –ps 1 10, ps 2 –ps 2 12.

Leg I ( Fig. 17 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 extremely club-shaped, sol ϕ2 finger-shaped. Length of solenidia: ω1 about 7, ω2 24, ϕ1 7, ϕ2 10. Setae s, pv’’, dTi, v’Ti, l’Ge, v’Ge and l’Fe sparsely barbed, all other setae smooth; all setae pointed.

Leg II ( Fig. 17 b). Setal formula: Tr1–Fe3–Ge3–Ti4(1)–Ta7(1). Ta with two small claws and small empodium. Sol ω thick, sol ω and ϕ finger-shaped, sol ω 15, sol ϕ 6. Setae pv’’, v’Ti, l’Ti and v’Ge sparsely barbed, all other setae smooth. Setae pv’ blunt, all other setae pointed.

LegIII ( Fig. 17 c). Setal formula: Tr1–Fe2–Ge2–Ti4(1)–Ta7. Ta with two small claws and small empodium. Sol ϕ 4, finger-shaped. Setae pl’’, v’Ge, l’Ge and v’Tr sparsely barbed, all other setae smooth; all setae pointed.

LegIV ( Fig. 17 d, Table 1 ). Setal formula: Tr1–Fe2–Ge1–Ti4(1)–Ta6. Distal Ta with two adhesive pads of differing size. Tarsal setae tc’, tc’’ are longest, length tc’ about 38, tc’’ 23. Seta dTi spine-like, smooth, pl’’ hooklike, smooth; dFe and tc’’ barbed, all other setae smooth. Seta u small, sol ϕ 7, thick, finger-shaped.

Differential diagnosis. Males of S. longipes can be differentiated from Archidispus , Heterodispus and Imparipes by the presence of accessory setigenous structures on the gnathosoma. Amongst the remaining males, S. longipes is most similar to S. longitarsus . The two species can be differentiated by S. longipes being shorter than S. longitarsus (idiosomal length about 125µm in S. longipes versus 155µm in S. longitarsus ), and by the shape of sol ϕ 1 on leg I which is considerably club-shaped in S. longipes and finger-shaped in S. longitarsus .

Material examined. 4 males from laboratory cultures based on females from manure; AUSTRIA: Dobl, 46°56'56.8"N, 15°22'26.2"E, 1988, leg. Ebermann.

Deposition of material. 2 males: Natural History Museum Vienna, Austria ( NHMW 27.644 ) ; 1 male: Institute of Zoology , University of Graz, Austria ; 1 male: 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 16. Scutacarus longipes male: a. dorsal view, b. ventral view.

FIGURE 17. Scutacarus longipes male: a. leg I, b. leg II, c. leg III, d. leg IV.