Scutacarus deserticolus Mahunka, 1969

Jagersbacher-Baumann, Julia & Ebermann, Ernst, 2016, Support for the underrepresented sex: new descriptions of scutacarid males (Acari, Heterostigmatina), Zootaxa 4179 (3), pp. 371-409 : 387-390

Scutacarus deserticolus Mahunka, 1969

( Figs. 1 , 3 , 12 , 13 )

MALE. Idiosoma length 120–180, n = 8.

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

Dorsum ( Fig. 12 a). Idiosoma with four sclerotized, very finely dotted plates. Most posterior plate forms dorsal cover for genital capsule. Length of dorsal setae: v about 14, sc 1 9, sc 2 43, c 1 37, c 2 36, d 36, e 17, f 53, h1 9. Setae v, sc 1, sc 2, c 1, c 2, d, e, f barbed, blunt-ended, sc 2, c 1, c 2, d, f with long barbs. h 1 and h 2 smooth, blunt-ended, h 2 minute. Distance between dorsal setae: v–v about 12, sc 1 –sc 1 28, sc 2 –sc 2 21, c 1 –c 1 29, c 2 –c 2 72, d–d 58, e–e 43, f–f 21, h 1 –h 1 27, h 2 –h 2 26.

Genital apparatus ( Figs. 3 e, 12a). Segments H and PS fused, form genital capsule. Length of genital plate (tergite H) about 52. Posterior edge of plate narrowed, ratio length: width of genital plate = 1: 0.52. Area posterior of h 1 with roundish, sucker-like structures or cavities. Aedeagus like in I. dispar .

Venter ( Fig. 12 b). Sternal plates very finely dotted. Ap1 weakly sclerotized, prosternal ap continuous from ap1 to sejugal ap; ap2, sejugal ap, ap3 complete, weakly sclerotized; ap4 incomplete, strongly sclerotized; ap5 strongly sclerotized; poststernal ap between ap3 and ap5 complete, clearly sclerotized. Length of ventral setae: 1 a about 12, 1 b 12, 2 a 12, 2 b 13, 3 a 10, 3 b 10, 3 c 11, 4 a 9, 4 b 12, 4 c 9, ps 1 2, ps 2 5. All setae smooth, short, pointed. Distance between ventral setae: 1 a –1 a about 14, 1 b –1 b 41, 2 a –2 a 20, 2 b –2 b 40, 3 a –3 a 23, 3 b –3 b 36, 3 c –3 c 62, 4 a –4 a 17, 4 b –4 b 7, 4 c –4 c 50, ps 1 –ps 1 12, ps 2 –ps 2 14.

Leg I ( Fig. 13 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 thin, finger-shaped. Length of solenidia: ω1 about 9, ω2 23, ϕ 1 6, ϕ2 12. Eupathidion ft’, setae v’Ti, v’’, l’’Ti, v’Ge, v’’Ge, l’Ge, dFe sparsely barbed, all other setae smooth; all setae pointed.

Leg II ( Fig. 13 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 24, sol ϕ 6. Setae u’, u’’, dTi, l’Fe, l’’Fe and v’Tr smooth, all other setae barbed, most only sparsely; all setae pointed.

Leg III ( Fig. 13 c). Setal formula: Tr1–Fe2–Ge2–Ti4(1)–Ta7. Ta with two small claws and small empodium. Sol ϕ 6, finger-shaped. Eupathidion tc’’, setae u’, u’’, pv’’, pl’’, dFe and v’Tr smooth, all other setae barbed, most only sparsely. Seta pl’’ somewhat blunt, all other setae pointed.

Leg IV ( Fig. 13 d, Table 1 ). Setal formula: Tr0–Fe2–Ge1–Ti4(1)–Ta6. Distal Ta with two adhesive pads of differing size. Tarsal setae tc’, tc’’ are longest, length tc’ about 74, tc’’ 46. Seta v’’Ti spine-like, smooth; pl hooklike, smooth; setae v’Fe, dFe, v’Ge, dTi, l’Ti, pv’ and pv smooth, all other setae barbed. Seta u minute, sol ϕ 7, thin, finger-shaped.

Differential diagnosis. Males of S. deserticolus can be differentiated from Archidispus , Heterodispus and Imparipes by the presence of accessory setigenous structures on the gnathosoma. They can be separated from all other males by their dorsal setation. Being morphologically most similar to S. tackei and S. tyrrhenicus , S. deserticolus differs by being larger than S. tackei (idiosoma length about 145µm in S. deserticolus versus 120µm in S. tackei ) and smaller than S. tyrrhenicus (165µm), and by possessing barbed setae v and sc 1. Moreover, the setation of leg IV differs between the three species ( Table 1 ).

Material examined. 8 males from laboratory cultures based on females collected from bumble bees; AUSTRIA: Dobl, 46°56'56.8"N, 15°22'26.2"E, 1987, leg. Ebermann.

Deposition of material. 2 males: Natural History Museum Vienna, Austria ( NHMW 27.642 ) ; 4 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 12. Scutacarus deserticolus male: a. dorsal view, b. ventral view.

FIGURE 13. Scutacarus deserticolus male: a. leg I, b. leg II, c. leg III, d. leg IV.