Home | Mesostigmata (Monogynaspida) Home | Glossary

Protogamasellus - hibernica group

Taxonomic Position

Cohort Gamasina

    Subcohort Dermanyssiae

  Superfamily Ascoidea

Family: Ascidae Voigts & Oudemans

Subfamily: Ascinae

Protogamasellus Karg - hibernicus species group

 

Diagnostic characters:

Ecology & Distribution.  These mites are small soil-inhabiting predators that feed on small invertebrates (e.g. nematodes, mites, springtails) and often occur as all female populations.

Similar taxa in key. Protogamasellus mica group species are particulate feeders, often have fungal hyphae or spores in their guts, and have an enlarged anal opening.   Ectoantennoseius Walter, Gamasellodes Athias-Henriot, Asca von Heyden, Antennoseius Berlese, Diseius Lindquist & Evans. 

Key to Adult Females of Rhodacarus-like Mites
(Rhodacaridae, Ologamasidae, Digamasellidae, Ascidae)

1.  Arthrodial process simple ..... 4

-   Arthrodial process produced as a brush .... 2

2.  Basitarsus IV with 4 setae (pl4 present) .... Pararhodacarus

-   Basitarsus IV with 3 setae (pl4 absent) ... 3

3.  Tectum with single median process or dentate .... Afrogamasellus

-   Tectum with median stalk y-shaped, usually with lateral tines ......... Afrodacarellus

4.  Scleronoduli present ........... 5

-   Scleronoduli absent ........... 10

5.  Tibia I with 4 ventral setae; palp apotele 3-tined ................ 6

-   Tibia I with 3 ventral setae; palp apotele 2-tined ................. 9

6.  3 scleronoduli (median unpaired);  j1-2, z1, and s1 on anterior margin of podonotal shield ............ 7

-   4 scleronoduli (median pair +/- fused);  j1 (but not j2), z1 and s1 on anterior margin of shield ........ 8

7.  Pretarsus I absent; without presternal platelets ................. Rhodacarus (+Mediorhodacarus)

-   Pretarsus I present; with 2 pairs of presternal platelets........................ Rhodacaropsis

8.  Podonotal shield entire ...................... Rhodacarellus

-   Podonotal shield divided between setae j3-j4; tectum denticulate-trifurcate .... Minirhodacarellus

9.  Tibia I with 5 (rarely 4) dorsal setae; 2 pairs of scleronoduli; sternal shield with 4 pairs of setae; anal opening normal ................................ Dendrolaelaps (Digamasellidae)

-   Tibia I with 6 dorsal setae; 3 scleronoduli; sternal shield with 3 pairs of setae (st4 in soft cuticle); anal opening enlarged ....................................... Protogamasellus mica Group (Ascidae)

10.  Sternal seta st4 on sternal shield .............. 11

-   Sternal  seta st4 in soft cuticle ................. 15

11.  Anal opening large; tibia I with 5 dorsal setae ............. Digamasellus (Digamasellidae)

-   Anal opening normal; tibia I with 6 dorsal setae ..................... 12

12.  Sternal shield strongly sclerotized throughout; tibia I with 4 ventral setae ....... Geogamasus (Ologamasidae)

-   Anterior region of sternal shield poorly sclerotized, setae st1 in soft or granulate cuticle; tibia I with 3 ventral setae ..................... 13

13.  Palp apotele 2-tined; coxa I without dorsal spine ..... 15

-      Palpapotele 3-tined: coxa I with dorsal spine ...... 14

14.   Presternal area granulate ................................ Protogamasellopsis

-     Presternal area with paired stacks of 4 presternal platelets ..... Rhodacarella

15.  Posterior margin of podonotal (at j6) and anterior margin of opisthonotal (at J1) shields with transverse lines; genu IV with 8 setae, tibia IV with 9 setae ......... Protogamasellus hibernicus Group (Ascidae)

-   Podonotal and opisthonotal shields without transverse lines; genu IV with 9 setae, tibia IV with 10 setae .......................................... Gamasellodes (Ascidae)

 

 

Key to genera in the subfamily Ascinae

 

1.  With holodorsal shield that captures the R-series ..... 2

-   Dorsal shield divided into two subequal shields; R-series setae in soft cuticle ..... 3

2.  Seta z1 present laterad seta j1 on anterior median region of dorsal shield; femur III with 7 setae; genu I with 13 setae; tibia II with 10 setae ..... Orthadenella (Blattisociidae)

-    Seta z1 absent; femur III with 6 setae; genu I with 12 setae; tibia II with 9 setae ..... Neojordensia

3.   Opisthonotal shield with 12 pairs of setae (J3, Z2, S1 absent); podonotal shield lacking setae j2, z1, z3; adult leg setation strongly neotenous, genua I-II-III-IV with 11-8-7-7 setae, tibiae with 11-7-7-7 setae; female with anal shield ..... Diseius

-     Opisthonotal shield with 15 or more pairs of setae (J3, Z2, S1 present); podonotal shield with setae j2, z3, sometimes z1; adult leg setation not strongly neotenous, minimum number of setae on genua 12-11-8-8, on tibiae 13-10-8-9; female with anal or ventrianal shield ..... 4

4.   Hypostome with corniculi bifid apically; anterior rostral setae thickened, spinelike; dorsal shield setae z1 absent  ..... Anephiasca

-    Hypostome with corniculi entire apically; anterior rostral setae of similar thickness to other hypostomal setae; dorsal shield setae z1 present or absent ..... 5

5.   Female with epigynial shield strongly rounded posteriorly and with small subtriangular ventrianal or anal shield bearing 3-5 setae; male with ventrianal shield united to peritrematal shields; soft body cuticle often with microtuberculate striae ..... 6

-     Female with epigynial shield truncate posteriorly and usually with well developed ventrianal shield (rarely anal shield) bearing 3-9 setae (including circumanal setae); male with ventrianal shield separate from peritrematal shields; soft body cuticle striae without microtubercles ..... 8

6.   Palps elongated, at least half as long as leg I; palp trochanter longer than femur; palp tibia almost 3 times as long as tarsus ..... Anystipalpus

-     Palps of normal length, about one-third as long as leg I; palp trochanter slightly shorter than femur; palp tibia twice as long as tarsus ... 7

7.   Legs I with ambulacra and claws ..... Antennoseius (Vitzthumia)

-     Legs I with out ambulacra and claws ..... Antennoseius (Antennoseius)

8.    Opisthonotal shield with setae Z4 & S5 usually approximate and inserted together on pair of prominent posterolateral tubercles; podonotal shield lacking setae z1,  j2 well behind level of j1; peritrematal shields of adults broad, truncate posteriorly; genu I with 12 setae (av2 absent) ..... Asca

-     Opisthonotal shield with setae Z4, S5 well separated, not borne on pair of strong tubercles; podonotal shield with setae z1 present; j2 tending to be displaced anteriorly, often in approximately transverse row with z1 and j1; peritrematal shields of adults narrow or of moderate width, tapering posteriorly; genu I with 13 setae (av2 present) ..... 9

9.      Podonotal shield with transverse line extending across surface at level of setae z6, opisthonotal shield with similar line at level of setae J1; paranal setae inserted close to anterior margin of anus; genu IV with 8 setae (pl1 absent); tibia IV with 9 setae (pl2 absent) ..... Protogamasellus

-        Dorsal shields without transverse lines extending completely across surface; paranal setae inserted closer to posterior margin of anus than to anterior margin; genu IV with 9 setae (pl1 present); tibia IV with 10 setae (pl2 present) ..... 10

10.      Sternal pore 3 in soft cuticle; setae r3 and Z5 club-shaped, densely plumose; gnathotectum denticulate; movable digit of chelicerae serrate ..... Ectoantennoseius

-        Sternal pore 3 on sternal shield; setae r3 and Z5 setiform, smooth to barbed; gnathotectum more or less smoothly trifurcate; movable digit of chelicerae usually with 4-6 teeth, not serrate ..... Gamasellodes

References

Evans GO & Till WM.  1979.  Mesostigmatic mites of Britain and Ireland (Chelicerata: Acari-Parasitiformes).  An introduction to their external morphology and classification.  Transactions of the Zoological Society of London 35 (2): 145-270.

Halliday RB, Walter DE & Lindquist EE.  1998.  Revision of the Australian Ascidae (Acarina: Mesostigmata).  Invertebrate Taxonomy 12: 1-54.

Karg W. 1993. Acari (Acarina), Milben. Parasitiformes (Anactinochaeta). Cohors Gamasina Leach. Raubmilben. (Second Edition). Die Tierwelt Deutschlands 59: 1-523.

Walter DE & Ikonen EK.  1989.  Species, guilds and functional groups: Taxonomy and behavior in nematophagous arthropods.  Journal of Nematology 21: 315-327.

Walter, D.E. & Lindquist, E.E.  1989.  Life history and behavior of ascid mites in the genus Lasioseius (Acari: Mesostigmata) from grassland soils in Colorado with taxonomic notes and a description of new species.  Canadian Journal of Zoology 67: 2797-2813.

Walter DE. & Lindquist EE.  1995.  The distribution of asexual ascid mites (Acari: Parasitiformes) does not support the biotic uncertainty hypothesis.  Experimental & Applied Acarology 19: 423-442.