1. Mesostigmata
Day – 3
Felicity Crotty

2. Mesostigmata 3 Suborders; One main Suborder with 5 Cohorts Gamasina
Sejida
Trigynaspida
Monogynaspida
Cercomegistina
Antennophorina
Heatherelina
Heterozerconina
Microgyniina
Uropodina
Gamasina
3 Suborders; One main Suborder with 5 Cohorts

3. 6 SEGMENTED
LEGS

6. Leg segmentation 1 2 3 4 5 6

7. Tarsus IV ventral setae av4/pv4 on sclerite between basi and telotarsus a key diagnostic feature!
If present = Sejida or Trigynaspida
If absent = Monogynaspida

9. Generalised venter St = sternal shield Ep = epigynal shield
V = ventral shield
An = anal shield
Mst = metasternal shields
Trt = tritiosternum

10. Hypostomal setae
If linear = Uropodina If triangular = other cohorts within monogynaspida

11. Uropodid Bingo I.D character
Pedofossa: recesses into which legs can be withdrawn

12. Epicriina
Bingo I.D character Dorsal shield entire, covered with polygonal network of tubercles Also identifiers include first pair of setae on small platelets.

13. Parasitina
Shield character I.D Apex of epigynal shield triangular and flanked by large metasternal shield bearing metasternal setae

14. Dermanyssina Shields

16. Oribatida
Day – 3
Felicity Crotty

17. Oribatida “Higher Oribatids” “Lower Oribatids” Brachypyline
Desmonomata
Enarthronota
Mixonomata
Paleosomata
Parhyposomata
Nothrina
Brachypylina
Astigmata
“Lower Oribatids”
Macropyline
“Higher Oribatids”
Brachypyline
5 Supercohorts; One with three cohorts

18. Defining characters of the 6 major Oribatid groups
Palaeosomata
Enarthronota
Parhyposomata
Mixonomata
Desmonomata & Brachypylina
Body Sclerotisation
weak
Weak to strong
Strong
Prodorsum type
Astegasime
Steg / astegasime
Stegasime
Body type
Dichoid
Dichoid / ptychoid
Dichoid / trichoid
Holoid
Notogastral Scissures
Absent or poorly defined
Present (1-3)
Present (1)
None
Femur
Divided
fused
Fused
Opisthosomal Gland
Absent
Present
Present (or secondarily lost)
Dichoid* difficult to see without sclerotisation

19. Body type
Subcapitulum
Body appears to be divided between legs II-III by a flexible sejugal furrow

20. Body type
Box mites
Lacks flexible sejugal furrow
3 segments

21. Body type Circumgastric scissure Fused coxisternum Postpedal furrow
Pygidium
Circumgastric scissure
Pronotaspis

22. Body type
Dichoid = body appearing to be divided between legs II-III by a flexible sejugal furrow (Acariformes).
Holoid = lacking flexible cuticle between legs II-III
Ptychoid - the ability of some oribatid mites to withdraw the legs between two body regions like a penknife being closed or a box being closed (hence box mites), and resulting in a seedlike appearance.  A derived form of dichoidy.
Trichoidy = having a body divided into three as in some lower Oribatida. 2 3 1

23. View if Oribatid on it’s back
STENARTHRIC
ANARTHRIC
ANARTHRIC
DIARTHRIC
PELOPSIFORM
ATTENUATE- EDENTATE

24. Gnathosoma
Trichobothria

25. First step to identification is it…?

26. Lower Oribatid - Macropyline
Genua of all legs similar to tibiae in size and shape (not knee-like)
Leg articulation not in deep acetabula
Trochanters I and II small but clearly external.
Paired aggenital and adanal plates often distinguishable
Coxisternal region often transversely divided by sejugal articulation
Subcaptiulum usually stenarthric

27. Higher Oribatid – Brachypyline
Genua of legs I-III (& often IV) shorter than tibiae and lacking intrinsic musculature – KNEE
Holoid body type
Distinct acetubula with trochanters I and II almost totally contained within
Apodemato-acetabular system of tracheae
Brachypyline venter unified rigid plate
Often evolved chelicerae & subcapitulum modified - diarthric

28. Acetabulum is a concave cavity in the body wall where a leg is inserted; in brachypyline oribatids these cavities are where the trochanter articulates with the coxae (fused to body wall) and may contain tracheal stigmata
Genua knee like

29. Examples of different Oribatids
Numbers relate to susceptibility to degraded environments
(5 = very susceptible)
Aoki 1996

30. Astigmata Cohort of Oribatida (in Desmonomata currently)
Weakly sclerotized (white / pale)
Slow moving
Lack respiratory stigmata or tracheae (respire through cuticle)
Lack segmentation
Body divided into 2 main regions gnathosoma and idiosoma (separated by sejugal furrow)

31. Astigmata

32. Astigmata Palps ONLY 2 segmented Chelicerae are chelate-dentate (3)
Have two genital papillae (4)
Male has aedeagus (4)
Anal opening often flanked by copulatory suckers (6)
A claw at apex of tarsus attached to a fleshy pretarsus, supported by sclerotised condylophores (7)

33. Astigmata biology Complete life cycle in several days to weeks
Lay up to 800 eggs in a month!
Adult average longevity days
Have an unusual heteromorphic deutonymphal (often phoretic)
Hypopus – highly resistant to adverse environmental conditions. Lacks mouthparts, often has suckerplate

34. Most important soil genera
Tyrophagus
Schwiebea
Rhizoglyphus
Glycyphagus
Lepidoglyphus
Histiostoma
Once you are certain it is an Astigmatid mite, it is very easy to identify to family using Dindal key! If you are feeling adventurous, you can also key to genera!

35. Prostigmata
Day – 3
Felicity Crotty

36. Prostigmata 4 Supercohorts; two of which have 2 cohorts within them
Eupodides
Anystides
Eleutherengonides
Labidostommatides
Anystina
Parasitengonina
Raphignathina
Heterostigmata
4 Supercohorts; two of which have 2 cohorts within them

37. Comparative Characters Prostigmata
Eupodina
Anystid
Parasitengona
Raphignathae
Heterostigmata
Palp segments 4 5
3 max
Palp tibia
Linear
Thumb claw No
stigmata
Base of chelicera
Absent
Anterior lateral on propodorsoma F
Peritremes
Yes
Naso
Pairs of trichobothria
1,2 1
0 imm; 1 F; 0 M
Empodial tenant hairs
No (II, III membraneous)

38. Trichobothria
Eye
Dorso-sejugal
Suture not distinct
Dorso-sejugal
suture
Genital papillae

40. Endeostig
Prostig

41. Examples of palp thumbclaw

42. Peritremes
Stigmata

44. Two different naming systems!

45. Same segmentation on palp
5 free leg segments
Coxa fused to ventral idiosoma

46. Paired claws
Paired claws and empodium

47. Solenidia
Different types of setae and Trichobothria (arrow)
Famulus

48. If Solenidia is supposed to be “Recumbent”, it is lying down alongside leg
Duplex setae: Normal setae alongside a Solenidia

49. Labidostomatidae 1 family Medium to large sclerotized mites
“Arnie” mite – look like it has a 6 pack! – Coxal fields expanded
2 pairs prodorsal trichobothria
Palps linear
Cheliceral bases separate, digits enlarged and chelate-dentate
Legs I tactile; legs II-IV walking
Predator

50. Parasitengona
Members of this group are well known to non-acarologists as velvet mites!
Red or green
Stigmata & peritremes located between cheliceral bases
Palp thumbclaw well developed
1 or 2 prodorsal trichobothria
Genital papillae usually present

51. Heterostigmata Very common Minute to medium sized Capitulum head-like
Palps linear and reduced to 3 or fewer segments
F: stigmata anterolaterally (on shoulders) of prodorsum.
Legs I often with tarsal claw as modified hook
F: legs IV often reduced or absent

52. Major character systems in Prostigmata
Chelicerae modified e.g. fused together / subcapitulum; reduction of fixed digit (Prostigmata are mainly fluid feeders)
Modification of the palp
Body setation
Leg setation
Modification of the pretarsus

53. Valerie Behan-Pelletier
Acknowledgments
Soil Mite Experts
Cal Welbourne
Valerie Behan-Pelletier
Roy Norton
David Walter