Acarapinae Schaarschmidt, 1959

Seeman, Owen D., Lindquist, Evert E. & Husband, Robert W., 2018, A new tribe of tarsonemid mites (Trombidiformes: Heterostigmatina) parasitic on tetrigid grasshoppers (Orthoptera), Zootaxa 4418 (1), pp. 1-54 : 5

Subfamily Acarapinae Schaarschmidt, 1959

Type genus: Acarapis Hirst, 1921

Description. As follows Lindquist (1986, p. 244), with following modifications as indicated in italics as variation noted to accommodate the genus Podotarsonemus and tribe Podotarsonemini.

Gnathosoma . Palpcoxal setae present in adults (Podotarsonemini), or lacking (Coreitarsonemini, Acarapini ). Cheliceral stylets robust, nearly straight or curved along their length (Podotarsonemini), attached to conspicuous basal levers.

Idiosomatic dorsum. Prodorsal stigmata of adult female situated anterolaterad of vertical setae, usually on protuberances ( Acarapini , Coreitarsonemini, some Podotarsonemini). Prodorsal bothridia lacking, their sensilla a slender seta (most Podotarsonemini), vestigial or lacking ( Acarapini , Coreitarsonemini, few Podotarsonemini) on adult female, and corresponding setae sc1 a slender seta (Podotarsonemini), minute, vestigial, or lacking ( Acarapini , Coreitarsonemini) on larva and adult male. Prodorsum of adult male also lacking setae v2, such that only two (v1, sc2 — Acarapini , most Coreitarsonemini) or three (v1, sc1, sc2 —Podotarsonemini, few Coreitarsonemini) pairs of setae usually present. Plate EF of adult male with one or two pairs of setae, sometimes retaining e in addition to f and cupules im. Genital capsule HPs of adult male with pliable adhesive copulatory flanges well-developed, reduced or absent.

Idiosomatic venter. Coxisternal plates I and II of adult each with one pair of setae (1a and 2a, respectively) but alveolar remnants of setae 1b and 2b present or lacking; plates I and II of larva with setae 1a and 2a present (Podotarsonemini) or vestigial or lacking ( Acarapini , Coreitarsonemini), and alveolar remnants of 1b and 2b present (Podotarsonemini) or lacking ( Acarapini , Coreitarsonemini). Metapodosomal venter of adult with no setae added to basic larval complement, such that coxisternal plates III with two pairs of setae, and plates IV lacking setae; plates III of larva with the basic two pairs of setae, 3a and 3b, present or lacking. Tegula of adult female either short and broadly truncate, or not developed. Aggenital plate of adult female lacking setae.

Idiosoma of larva moderately (Podotarsonemini) to greatly ( Acarapini , Coreitarsonemini) distensible due to extensive plication of membranous cuticle between various plates.

Legs. Leg I of adult female with single, normal claw on pretarsus ( Acarapini , Coreitarsonemini) or claw absent on well-developed ambulacrum (Podotarsonemini); adult male with claw single ( Acarapini ), paired (Coreitarsonemini) or absent on well-developed ambulacrum (Podotarsonemini); larva with claw paired ( Acarapini , Coreitarsonemini, few Podotarsonemini) or absent on well-developed ambulacrum (most Podotarsonemini). Leg III of adult female with trochanter no longer than femorogenu, and retaining a somewhat subtriangular form with articulated mobility similar to that of larva and adult male. Leg III of adult male with femur and genu fused or separate. Leg IV of adult female with zero to two (Podotarsonemini) or two or three setae on femorogenu (a second genual seta, lʹʹ, sometimes present) ( Acarapini , Coreitarsonemini), and with two or rarely three setae on tibiotarsus (a second long tibial seta, v″, rarely present). Leg IV of adult male with or without a seta on trochanter; with tibia and tarsus separate (few Coreitarsonemini, few Podotarsonemini), fused (most Coreitarsonemini) or tarsus absent ( Acarapini , most Podotarsonemini); tarsal setae present, vestigial, or lacking; tarsal claw vestigial or usually lacking.

Number of setae and solenidia on femur, genu, tibia, and tarsus variable, but consistent within Acarapini and Coreitarsonemini, more variable in Podotarsonemini; see descriptions of tribes in Lindquist (1986). Tibial sensory cluster of leg I of adult incomplete, lacking φ1 ( Acarapini , Coreitarsonemini) and sometimes φ2 (Coreitarsonemini) but retaining seta kʹʹ, or retaining φ1 and lacking kʹʹ (Podotarsonemini). Tarsal setation of leg I lacking plʹ and sometimes plʹʹ; on adult female setae ftʹ-ftʹʹ lacking, on adult male setae ftʹ-ftʹʹ well developed (Podotarsonemini) or lacking ( Acarapini , Coreitarsonemini); unguinals uʹ-uʹʹ, when present, well separated from each other. Femur I setation complete ( Acarapini , Coreitarsonemini, some Podotarsonemini) or incomplete (some Podotarsonemini) but seta lʹʹ always present. Tarsus II lacking dorsoproximal spinelike seta plʹʹ. Tarsi II and III with seta u″ present or absent; with unguinal uʹ spinelike or slender. Tarsus III with seta pvʹ expressed on adult of both sexes (exceptionally absent on male) but not on larva. Leg III with one femoral seta ( Acarapini , Coretarsonemini) or femoral setae absent (Podotarsonemini).

Larvae and adults parasitic on insects.