Rhodacaropsis

Mesostigmata

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Taxonomy

updated 2025

Name

Rhodacaropsis Willmann

Classification

Superorder Parasitiformes » Order Mesostigmata » Suborder Monogynaspida » Infraorder Gamasina » Hyporder Dermanyssiae » Superfamily Rhodacaroidea » Family Rhodacaridae » Genus Rhodacaropsis

Diagnostic characters

  • Divided dorsal shielddivided dorsal shield:
    in Mesostigmata, adult mites have two usually subequal dorsal shields.
    with 3 scleronoduliscleronoduli:
    3-4 light refractile structures, sometimes comma-shaped, in the podonotal region of many Rhodacaroidea and the genus Protogamasellus (Ascidae) in the Mesostigmata.  
    on podonotal shieldpodonotal shield:
    the anterior shield in mesostigmatans with divided dorsal shields.  
    and 4 pairs of setae (j12, z1, s1) on its anterior margin
  • Peritremes highly reduced or absent
  • Legs I with pretarsustarsal apotele:
    (also pretarsus) the most distal segments of legs and palps bearing the claws and empodium
  • Femurfemur:
    (pl. femora) major leg segment between trochanter and genu; often subdivided into a basifemur and a telofemur.
    III with 4 setae
  • Sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    with 4 pairs of setae; 2 pairs of presternal plateletspresternal platelets:
    small sclerotized plates anterior to the sternal shield and laterad or posteriad the base of the tritosternum in some Mesostigmata.
    .

Similar taxa

Species of Rhodacarus lack both pretarsustarsal apotele:
(also pretarsus) the most distal segments of legs and palps bearing the claws and empodium
I and presternal plateletspresternal platelets:
small sclerotized plates anterior to the sternal shield and laterad or posteriad the base of the tritosternum in some Mesostigmata.
.

Key to adult females of Rhodacarus-like mites
(Rhodacaridae, Ologamasidae, Digamasellidae, Ascidae)

  1. Arthrodial process simplesimple:
    unadorned; simple setae are needle-like and without hairs or pectins.
    .............................. 4
    - Arthrodial process produced as a brush.............................. 2

  2. Basitarsusbasitarsus:
    a basal subdivision of the tarsus.
    IV with 4 setae (pl4 present).............................. Pararhodacarus
    - Basitarsusbasitarsus:
    a basal subdivision of the tarsus.
    IV with 3 setae (pl4 absent).............................. 3

  3. Tectumgnathotectum:
    (= epistome, tectum) an often membranous dorsal projection of the anterior margin of the basis capitulum in Mesostigmata; often diagnostic at family-, genus- or species-levels; also often difficult to see without high magnification and good optics.
    with single median process or dentate.............................. Afrogamasellus
    - Tectumgnathotectum:
    (= epistome, tectum) an often membranous dorsal projection of the anterior margin of the basis capitulum in Mesostigmata; often diagnostic at family-, genus- or species-levels; also often difficult to see without high magnification and good optics.
    with median stalk y-shaped, usually with lateral tines.............................. Afrodacarellus

  4. Scleronoduli present.............................. 5
    - Scleronoduliscleronoduli:
    3-4 light refractile structures, sometimes comma-shaped, in the podonotal region of many Rhodacaroidea and the genus Protogamasellus (Ascidae) in the Mesostigmata.  
    absent.............................. 10

  5. Tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 4 ventral setaeventral setae:
    in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (JvZvLv) with 1-5 transverse row designations.
    ; palp apotelepalptarsal apotele:
    (= palp apotele, palptarsal claw) the most distal segment of the palp; absent in Acariformes, claw-like in Opilioacarida, and a subdistal, tined structure in the Mesostigmata.
    3-tined.............................. 6
    - Tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 3 ventral setaeventral setae:
    in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (JvZvLv) with 1-5 transverse row designations.
    ; palp apotelepalptarsal apotele:
    (= palp apotele, palptarsal claw) the most distal segment of the palp; absent in Acariformes, claw-like in Opilioacarida, and a subdistal, tined structure in the Mesostigmata.
    2-tined.............................. 9

  6. 3 scleronoduli (median unpaired);  j12, z1, and s1 on anterior margin of podonotal shieldpodonotal shield:
    the anterior shield in mesostigmatans with divided dorsal shields.  
    .............................. 7
    - 4 scleronoduli (median pair +/- fused);  j1 (but not j2), z1 and s1 on anterior margin of shield.............................. 8

  7. Pretarsustarsal apotele:
    (also pretarsus) the most distal segments of legs and palps bearing the claws and empodium
    I absent; without presternal plateletspresternal platelets:
    small sclerotized plates anterior to the sternal shield and laterad or posteriad the base of the tritosternum in some Mesostigmata.
    .............................. Rhodacarus (+Mediorhodacarus)
    - Pretarsustarsal apotele:
    (also pretarsus) the most distal segments of legs and palps bearing the claws and empodium
    I present; with 2 pairs of presternal plateletspresternal platelets:
    small sclerotized plates anterior to the sternal shield and laterad or posteriad the base of the tritosternum in some Mesostigmata.
    .............................. Rhodacaropsis

  8. Podonotal shieldpodonotal shield:
    the anterior shield in mesostigmatans with divided dorsal shields.  
    entire.............................. Rhodacarellus
    - Podonotal shieldpodonotal shield:
    the anterior shield in mesostigmatans with divided dorsal shields.  
    divided between setae j3j4; tectumgnathotectum:
    (= epistome, tectum) an often membranous dorsal projection of the anterior margin of the basis capitulum in Mesostigmata; often diagnostic at family-, genus- or species-levels; also often difficult to see without high magnification and good optics.
    denticulate-trifurcate.............................. Minirhodacarellus

  9. Tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 5 (rarely 4) dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    setae; 2 pairs of scleronoduliscleronoduli:
    3-4 light refractile structures, sometimes comma-shaped, in the podonotal region of many Rhodacaroidea and the genus Protogamasellus (Ascidae) in the Mesostigmata.  
    ; sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    with 4 pairs of setae; anal opening normal.............................. Dendrolaelaps (Digamasellidae)
    - Tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 6 dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    setae; 3 scleronoduliscleronoduli:
    3-4 light refractile structures, sometimes comma-shaped, in the podonotal region of many Rhodacaroidea and the genus Protogamasellus (Ascidae) in the Mesostigmata.  
    ; sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    with 3 pairs of setae (st4 in soft cuticle); anal opening enlarged.............................. Protogamasellus mica Group (Ascidae)

  10. Sternal seta st4 on sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    .............................. 11
    - Sternal  seta st4 in soft cuticle.............................. 15

  11. Anal opening large; tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 5 dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    setae.............................. Digamasellus (Digamasellidae)
    - Anal opening normal; tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 6 dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    setae.............................. 12

  12. Sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    strongly sclerotized throughout; tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 4 ventral setaeventral setae:
    in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (JvZvLv) with 1-5 transverse row designations.
    .............................. Geogamasus (Ologamasidae)
    - Anterior region of sternal shieldsternal shield:
    a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
    poorly sclerotized, setae st1 in soft or granulate cuticle; tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    I with 3 ventral setaeventral setae:
    in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (JvZvLv) with 1-5 transverse row designations.
    .............................. 13

  13. Palp apotelepalptarsal apotele:
    (= palp apotele, palptarsal claw) the most distal segment of the palp; absent in Acariformes, claw-like in Opilioacarida, and a subdistal, tined structure in the Mesostigmata.
    2-tined; coxacoxa:
    the basal segment of the leg, articulating with (Parasitiformes) or fused to (Acariformes) the body wall.
    I without dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    spine .............................. 15
    - Palpapotele 3-tined: coxacoxa:
    the basal segment of the leg, articulating with (Parasitiformes) or fused to (Acariformes) the body wall.
    I with dorsaldorsal:
    relating to the upper or back side; opposed to ventral.
    spine.............................. 14

  14. Presternal area granulate.............................. Protogamasellopsis
    - Presternal area with paired stacks of 4 presternal plateletspresternal platelets:
    small sclerotized plates anterior to the sternal shield and laterad or posteriad the base of the tritosternum in some Mesostigmata.
    .............................. Rhodacarella

  15. Posteriorposterior:
    the back part of the body or towards that region in comparison, e.g., 'posterior to'.
    margin of podonotalpodonotal:
    relating to the dorsal podosoma, the region of the idiosoma over the legs.
    (at j6) and anterior margin of opisthonotalopisthonotal:
    dorsal opisthosoma.
    (at J1) shields with transverse lines; genugenu:
    (pl. genua) (= patella) the 4th leg segment, between the femur and tibia.
    IV with 8 setae, tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    IV with 9 setae.............................. Protogamasellus hibernicus Group (Ascidae)
    - Podonotalpodonotal:
    relating to the dorsal podosoma, the region of the idiosoma over the legs.
    and opisthonotalopisthonotal:
    dorsal opisthosoma.
    shields without transverse lines; genugenu:
    (pl. genua) (= patella) the 4th leg segment, between the femur and tibia.
    IV with 9 setae, tibiatibia:
    (pl. tibiae) the leg segment between the genu and the tarsus.
    IV with 10 setae.............................. Gamasellodes (Ascidae)

References

  • Athias-Henriot 1961aAthias-Henriot 1961a:
    Athias-Henriot C. 1961a. Mesostigmatides (Urop. excl.) edaphiques Mediterraneans (Acaromorpha, Anactinotrichida). Acarologia 3: 381–509.
  • Lee 1970Lee 1970:
    Lee DC. 1970. The Rhodacaridae (Acari: Mesostigmata); classification, external morphology and distribution of genera. Records of the South Australian Museum 16: 1-219.
  • Loots 1969Loots 1969:
    Loots GC. 1969. Notes on Rhodacarus Oudemans and its related genera with descriptions of new species from the Ethiopian region. Publicações Culturais da Companhia de Diamantes de Angola 81: 45-82.
  • Moraza 2004Moraza 2004:
    Moraza ML. 2004. Rhodacarella, a new genus of Rhodacaridae mites from North America (Acari: Mesostigmata: Rhodacaridae). Zootaxa 470: 1-10.
 Rhodacaropsis
Rhodacaropsis