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Mesostigmata Day – 3 Felicity Crotty.

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Presentation on theme: "Mesostigmata Day – 3 Felicity Crotty."— Presentation transcript:

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




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Pedofossa: recesses into which legs can be withdrawn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

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

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