Rhodacaroidea, Oudemans, 1902

Castilho, Raphael C., De Moraes, Gilberto J. & Halliday, Bruce, 2012, 3471, Zootaxa 3471, pp. 1-69 : 19-20

Key to world families of Rhodacaroidea and genera of Rhodacaridae

(adult females)

1. Seta st 4 on metasternal platelet or on soft integument......................................................... 2

- Seta st 4 on sternal shield................................................................................ 3

2 (1). Dorsal shield setae strongly pilose and inserted on long stalks; with six dorsal setae on tibia I; genu IV with total of ten setae; tibia IV typically with ten setae.................................................... Oriflammella (Ologamasidae)

- Dorsal shield setae not inserted on stalks; with five dorsal setae on tibia I; genu IV with total of 8–10 setae; tibia IV typically with eight setae................................................................. Halolaelapidae [ Fig. 1 A–B]

3 (1). With anal shield (bearing only circumanal setae); tibia I with four dorsal setae; genu IV with 11 setae, five of which dorsal; distal separated section of laciniae corresponding to about 30% of the total length of the tritosternum................................................................................................... Teranyssidae [ Fig. 2 A–C]

- With ventrianal shield, bearing 1–9 pairs of preanal setae; tibia I with 3–6 dorsal setae; genu IV usually with 7–10 setae, 4–5 of which dorsal (if with 11, then six of these dorsal); distal separated section of laciniae over 50% of the total length of the tritosternum.......................................................................................... 4

4 (3). With attenuate chelicera; palp with four segments (fused tibia and tarsus); corniculi aciculate. Laelaptonyssidae [ Fig. 3 A–C]

- With normal chelicera, not attenuate; palp with five segments; corniculi typically robust, horn-like..................... 5

5 (4). Palp tarsal claw two-tined; tibia I with five dorsal setae; genu and tibia IV with 6–8 setae, including four and three dorsal setae respectively................................................................... Digamasellidae [ Fig. 4 A–D]

- Palp tarsal claw three-tined; tibia I with six dorsal setae; genu and tibia IV with 9–10 setae, including five and four dorsal setae respectively.......................................................................................... 6

6 (5). Usually with internal densely sclerotised structures between levels of setae j 5 and j 6 (scleronoduli; absent in Interrhodeus , Pennarhodeus , Protogamasellopsis and in Afrogamasellus luberoensis kalibuensis ); podonotal and opisthonotal shields separate (except in Afrogamasellus luberoensis ); usually with desclerotised bands of punctate integument along posterior margin of podonotal, anterior margin of opisthonotal, anterior margin of sternal, posterior margin of genital and anterior margin of ventrianal shields.............................. Rhodacaridae [ Fig. 5 A–D].......................... 7

- Nearly always without scleronoduli; podonotal and opisthonotal shields fused or not; without desclerotised bands of punctate integument................................................ Ologamasidae (other than Oriflammella ) [ Fig. 6 A–D]

7 (6). Peritreme greatly reduced, not reaching anterior margin of coxa IV.............................................. 8

- Peritreme extending anteriorly at least to level of middle of coxa III.............................................. 9

8 (7). Podonotal shield with three scleronoduli, 21–22 pairs of setae and with transverse suture between setae j 4 and j 5................................................................................ Rhodacaropsis Willmann [ Fig. 7 A–D]

- Podonotal shield with two scleronoduli, 14 pairs of setae and without transverse suture between setae j 4 and j 5............................................................................ Binodacarus Castilho & Moraes [ Fig. 8 A–D]

9 (7). Ventrianal shield>1.8 times as long as wide, encompassing only 1–2 pairs of preanal setae; podonotal shield with 16 pairs of setae......................................................... Protogamasellopsis Evans & Purvis [ Fig. 9 A–D]

- Ventrianal shield ≤1.6 times as wide as long, encompassing ≥4 pairs of preanal setae; podonotal shield with ≥17 pairs of setae ( Rhodacarellus arcanus with 16)........................................................................ 10

10 (9). Scleronoduli absent; cheliceral arthrodial process a short coronet-like fringe or an elongate, three-tined structure......... 11

- Scleronoduli nearly always present; cheliceral arthrodial process a short coronet-like fringe or shaped like a cylindrical brush (if scleronoduli absent, in Afrogamasellus luberoensis kalibuensis , cheliceral arthrodial process shaped like a cylindrical brush) ................................................................................................... 12

11 (10).Dorsal setae pilose; ventrianal shield 0.7 times longer than wide; with a pair of rounded metapodal platelets; seta h 3 in transversal line and mediad to h 2............................................... Pennarhodeus Karg [ Fig. 10 A–D]

- Dorsal setae smooth; ventrianal shield as long as wide; with a pair of elongate metapodal platelets; seta h 3 posterior and mediad to h 2............................................................... Interrhodeus Karg [ Fig. 11 A–D]

12 (10).Podonotal shield with three scleronoduli; cheliceral arthrodial process a short coronet-like fringe..................... 13

- Podonotal shield with four scleronoduli; cheliceral arthrodial process a short coronet-like fringe or shaped like a cylindrical brush.............................................................................................. 14

13 (12).Fixed cheliceral digit with at least nine teeth; podonotal shield with V-shaped line posterior of setae j 4, z 3 and s 2............................................................................ Multidentorhodacarus Karg [ Fig. 12 A–D]

- Fixed cheliceral digit with at most six teeth; podonotal shield with or without V-shaped line posterior of setae j 4, z 3 and s 2......................................................................... Rhodacarus Oudemans [ Fig. 13 A–D]

14 (12).With two pairs of presternal platelets; with four pairs of setae (j 1, j 2, z 1 and s 1) near anterior margin of podonotal shield...................................................................... Mediorhodacarus Shcherbak [ Fig. 14 A–D]

- With 0–1 pair of presternal platelets; with two (j 1 and z 1) or three (j 1, j 2 and z 1) pairs of setae near anterior margin of podonotal shield..................................................................................... 15

15 (14).Cheliceral arthrodial process shaped like a cylindrical brush................................................... 16

- Cheliceral arthrodial process a short coronet-like fringe...................................................... 18

16 (15).With three pairs of metapodal platelets; basitarsus IV with four setae (seta pl 4 present)..................................................................................... Pararhodacarus Jordaan, Loots & Theron [ Fig. 15 A–D]

- With 1–2 pairs of metapodal platelets; basitarsus IV with three setae (seta pl 4 absent, except in Afrodacarellus camaxiloensis ) ................................................................................................... 17

17 (16).Epistome with an anteromedian extension wider at the base, not flanked by anterolateral extensions (in A. congoensis and A. uviraensis epistome with an anteromedian extension narrower at the base, flanked by a pair of anterolateral extensions); with 0–1 pair of presternal platelets; sternal shield with anterior margin distinct; genital shield shorter than posterior width, sometimes subequal................................................. Afrogamasellus Loots & Ryke [ Fig. 16 A–D]

- Epistome with an anteromedian extension that may be of about uniform width along its length, narrower or wider at the base; usually flanked by one or more pairs of anterolateral extensions ( A. euungulae with anterior region triangular); without presternal platelets; sternal shield with anterior margin indistinct and with region anterior to first pair of lyrifissures (iv 1) lightly sclerotised and punctate; genital shield usually longer than posterior width, sometimes subequal........................................................................................ Afrodacarellus Hurlbutt [ Fig. 17 A–D]

18 (15).Podonotal shield with a transverse line between setae j 4 and j 5.............. Minirhodacarellus Shcherbak [ Fig. 18 A–D]

- Podonotal shield without transverse line between setae j 4 and j 5............................................... 19

19 (18).Epistome with an anteromedian extension (with one to several pairs of spines along its mid-length) wider at the base, not flanked by anterolateral extensions; basitarsus IV with four setae (pl 4 present)................................................................................................... Paragamasellevans Loots & Ryke [ Fig. 19 A–D]

- Epistome with a smooth or serrate anteromedian extension of uniform width along its length or wider at base, usually flanked by at least one pair of smooth or serrate anterolateral extensions; basitarsus IV with three setae (pl 4 absent)............. 20

20 (19).Podonotal shield ornamented; with a pair of roundish metapodal platelets (indistinct or absent in P. acutus )........................................................................................ Poropodalius Karg [ Fig. 20 A–D]

- Podonotal shield smooth (ornamented in R. unicus ); with a pair of elongate metapodal platelets (a second pair of small, rounded metapodal platelets may be present)................................. Rhodacarellus Willmann [ Fig. 21 A–D]