Heterodispus Paoli, 1911

Jagersbacher-Baumann, Julia & Ebermann, Ernst, 2016, Support for the underrepresented sex: new descriptions of scutacarid males (Acari, Heterostigmatina), Zootaxa 4179 (3), pp. 371-409 : 372-378

Genus Heterodispus Paoli, 1911

Type species Heterodispus elongatus Trägårdh, 1905 , by original designation

Heterodispus foveatus Jagersbacher-Baumann and Ebermann, 2012 ( Figs. 1–4 )

MALE. Idiosoma length 120–150, n = 3.

Gnathosoma ( Fig. 1 a) extended, tube-shaped. One pair of finger-shaped solenidia, two pairs of dorsal setae ch 1 and ch 2, thin, smooth, one ventral pair of setae su longer, barbed.

Dorsum ( Fig. 2 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 28, sc 2 39, c 1 33, c 2 41, d 40, e 29, f 34, h 1 12. Setae v smooth, sc 1, sc 2, c 1, c 2, d, e, f barbed; sc 2, c 2 and d blunt-ended, all other setae pointed. Setae h 1 and h 2 smooth, h 2 minute. Distance between dorsal setae: v–v about 15, sc 1 –sc 1 10, sc 2 –sc 2 32, c 1 –c 1 49, c 2 –c 2 93, d–d 61, e–e 52, f–f 24, h 1 –h 1 26, h 2 –h 2 21.

Genital apparatus ( Figs. 2 a, 3a). Segments H and PS fused, form genital capsule. Length of genital plate (tergite H) about 54. Posterior edge of plate narrowed, ratio length: width of genital plate = 1: 0.49. Heart-shaped area posterior of h 1 with surface with roundish-hexagonal, sucker-like structures or cavities with a diameter of about 2. Aedeagus transversely striated, internally forming a loop; continues internally as ductus ejaculatorius leading into a seminal vesicle.

Venter ( Fig. 2 b). Sternal plates finely dotted. Ap1 clearly sclerotized, prosternal ap almost continuous from ap1 to sejugal ap; ap2, ap4 complete, weakly sclerotized; ap3, ap5 strongly sclerotized; ap3 incomplete; poststernal ap incomplete, between ap4 and ap5 weakly sclerotized. Length of ventral setae: 1 a about 19, 1 b 15, 2 a 16, 2 b 14, 3 a 18, 3 b 14, 3 c 19, 4 a 13, 4 b 18, 4 c 14, ps 1 2, ps 2 7. Setae ps smooth, all other setae sparsely barbed, pointed. Distance between ventral setae: 1 a –1 a about 13, 1 b –1 b 39, 2 a –2 a 26, 2 b –2 b 41, 3 a –3 a 27, 3 b –3 b 40, 3 c –3 c 76, 4 a –4 a 18, 4 b –4 b 13, 4 c –4 c 52, ps 1 –ps 1 12, ps 2 –ps 2 21.

Leg I ( Fig. 4 a). Setal formula: Tr1–Fe3–Ge4–Ti6(2)–Ta13(2). Ta with one small padded claw. Sol ω 1 thick and finger-shaped, ω 2 very thin, ϕ 1 and ϕ 2 thin, baculiform. Length of solenidia: ω 1 about 17, ω 2 9, ϕ 1 7, ϕ 2 7. Eupathidia p’, p’’ and ft’’ as well as setae u’, u’’, v’’Ti and v’Tr smooth, all other setae barbed, some only sparsely. Seta k blunt, all other pointed.

Leg II ( Fig. 4 b). Setal formula: Tr1–Fe3–Ge3–Ti4(1)–Ta7(1). Ta with two small claws and small empodium. Sol ω thick, finger-shaped, ϕ baculiform, ω 15, ϕ 4. Eupathidion tc’’, setae u’, u’’, v’’Ti smooth, all other setae barbed, some only sparsely; all setae pointed.

Leg III ( Fig. 4 c). Setal formula: Tr1–Fe2–Ge2–Ti4(1)–Ta7. Ta with two small claws and empodium. Sol ϕ 6, thick, club-shaped. Seta u’’ smooth (?), all other seate barbed, some only sparsely; all setae pointed. Leg IV ( Fig. 4 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 91, tc’’ 63; pv’’ spine-like, smooth, all other setae barbed, pointed. Seta u minute. ϕ 12, thin.

leg IV Reference

Trochanter Femur Genu cone- or spine-like modified

setae

Scutacarus agypticus needs revision Yousef & Metawally 1973 Diversipes exhamalatus needs revision Michael 1886

Differential diagnosis. The male of Heterodispus foveatus is separated from males of all other genera by the characteristic presence of a looped aedeagus which has already been described for the congeneric H. cordidiscus ( Jagersbacher-Baumann & Ebermann 2012) . The male of H. foveatus can be differentiated from H. cordidiscus by longer dorsal setae sc 1, c 1, e and f, by all ventral setae being barbed and by the shape of the genital plate, which is less heart-shaped in H. foveatus than in H. cordidiscus , where it is the name-giving feature. Solenidia ω 1 and ω 2 on legs I and II are longer in H. foveatus than in H. cordidiscus , and the setation of leg IV also differs ( Table 1 ).

Material examined. 3 males from laboratory cultures based on females from sandy ground with roots; EGYPT: Luxor, Nile riverside, 25°41’38.02’’N, 32°37’41.18’’E. 1985, leg. Ebermann.

Deposition of material. 1 male: Natural History Museum Vienna, Austria ( NHMW 27.638 ) ; 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 2. Heterodispus foveatus male: a. dorsal view, b. ventral view.

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 4. Heterodispus foveatus male: a. leg I, b. leg II, c. leg III, d. leg IV.

Tables

TABLE 1. Setation on leg IV (trochanter, femur and genu) and modified setae on leg IV of all known scutacarid males.

Archidispus amarae 1	2	0	pv'' (small), v''Ti	Ebermann 1994
Archidispus armatus 1	2	0	pv'' (small), v''Ti (small)	Ebermann 1994
Archidispus magnififcus 1	2	0	pv'' (very small), v''Ti (small)	Ebermann 1994
Archidispus minor 1	2	0	pv'' (very small)	Ebermann 1994
Heterodispus cordidiscus 1	2	1	pl'', v''Ti	Jagersbacher-Baumann & Ebermann 2012
Heterodispus foveatus 1	2	1	pv''	this publication
Imparipes apicola 1	2	0	pv'', v''Ti	Delfinado & Baker 1976
Imparipes brevitarsus 1	2	1	pl'', pv'', v''Ti	Ebermann 1981a
Imparipes dispar 1	2	1	v''Ti (thin)	this publication
Imparipes histricinus 1	2	0	pv'', v''Ti	Ebermann 1982
Imparipes kataglyphi 1	2	0	pv'', v''Ti	Khaustov & Chydyrov 2004
Imparipes kugitangensis 1	2	1	v''Ti (thin)	Khaustov & Chydyrov 2004
Lamnacarus ornatus 1	1	1	dTi, l'Ti, Solenidion φ	this publication
Lophodispus irregularis 1	2	1	pl'', pv'', v''Ti (very small)	Ebermann 1981b
Scutacaropsis 1 baculitarsus	2	1	(pl''), pv'', v''Ti	Norton & Ide 1974
Scutacarus acarorum 0	2	1	v''Ti	this publication
Scutacarus deserticolus 0	2	1	v''Ti	this publication
Scutacarus ellipticus 1	1	1	v''Ti	this publication
Scutacarus fragariae 0	1	0	v''Ti	Rack 1975
Scutacarus longipes 1	2	1	dTi	this publication
Scutacarus longitarsus 1	2	1	dTi	this publication
Scutacarus peractus 1	1	0	v''Ti (small)	Ebermann 1983
Scutacarus tackei 1	1	1	v''Ti	this publication
Scutacarus tyrrhenicus 1	2	1	v''Ti	this publication