Australian Arrenurus 
259 
2. Cauda as wide as long.3 
Cauda distinctly longer than wide.4 
3. Cauda posteriorly with a large, hyaline area 
(K.O. Viets 1978, figures 33, 34). 
. A. victorianus K.O. Viets 
Cauda without hyaline area (Cook 1986, figure 
1649). A. cheetus Cook 
4. Cauda with triangular posterolateral 
projections (Cook 1986, figure 1651). 
. A. otodus Cook 
Cauda without triangular posterolateral 
projections.5 
5. Posterior margin of cauda with a medial 
projection (Cook 1986, figure 1639). 
. A. margatellus Cook 
Posterior margin of cauda without a projection 
.6 
6. Body colour blue, rudimentary petiole dagger¬ 
like (Figure 26). A. caemleus sp. nov. 
Body colour yellow or orange.7 
7. Two closely situated rudimentary petioles 
present, these peg-like (Figure 45). 
. A. vanderpalae Smit 
Two well separated rudimentary petioles 
present, these rounded (Figure 31). 
. A. gilzms sp. nov. 
8. Dorsal furrow incomplete (Figure 41). 
. A. thienenmmi K.O. Viets 
Dorsal furrow complete.9 
9. Cauda short, almost as wide as long (Walter 
1929, figure 32). A. harpagopalpus Walter 
Cauda longer than wide.10 
10. Posterior margin of cauda triangular shaped 
(K.O. Viets 1984, figure 51). 
. A. rostratus degeneratus K.O. Viets 
Posterior margin of cauda rounded (Cook 
1967, figure 835). A. rostratus Daday 
Key to the males of Arrenurus (Brevicaudatunis) 
subgen. nov. 
1. Cauda posteriorly with large hump (Smit 1992, 
figure 59). A. roobeeki Smit 
Cauda without large hump.2 
2. Anterior body part with three large humps, 
posterior margin of dorsal shield medially 
convex (Smit 1992, figure 55). 
.«.... A. tricornutus K. Viets 
Anterior body part with two large humps, 
posterior margin of dorsal shield medially 
straight (Figure 36). A. lohmanni Piersig 
Key to the males of Arrenurus (Micruracarus) 
1. Dorsal shield covering entire dorsum (Smith 
and Ffarvey 1989, figure 1). 
. A. kilchingi Smith and Harvey 
Dorsal shield smaller than dorsum.2 
2. Petiole absent, body posteriorly with a 
concavity, genital plates separated, not fused 
with gonopore (Figure 61). 
. A. separatus sp. nov. 
Petiole present.3 
3. Petiole tong-shaped.4 
Petiole not tong-shaped.5 
4. Petiole connected with cauda by a hyaline 
area, petiole open posteriorly (Lundblad 
1947, figure 48A) ....A. forpicatoides Lundblad 
Petiole separated from cauda, petiole almost 
closed posteriorly (Figure 48). 
. A. anbangbang sp. nov. 
5. Petiole chisel-shaped (Figure 52). 
... A. jabiruensis sp. nov. 
Petiole dagger-like (Figure 57). 
. A. purpureus sp. nov. 
Key to the males of Arrenurus (Truncaturus) 
1. Posterior body margin with a notch (Cook 
1986, figure 1656). A. haswelli Cook 
Posterior body margin without notch.2 
2. Body elongated (Lundblad 1947, figure 49A)... 
. A. tasmanicus Lundblad 
Body short (Lundblad 1947, figure 50A). 
. A. novaehollandiae Lundblad 
Key to the males of Arrenurus (Dividuracarus) 
subgen. nov. 
1. Body colour orange-yellow, ventral body part 
extending well beyond dorsum, D1 on small 
humps (Figure 66). A. tripartilus sp. nov. 
Body colour brownish-green, ventral body 
part extending a little beyond dorsum, D1 
on large humps (Figure 71). 
. A. gereckei sp. nov. 
Key to the females (all subgenera) 
1. Genital valves with chitinized patches.2 
Genital valves without chitinized patches .... 13 
2. Chitinized patches small, consisting of only a 
small strip at anterior and posterior part of 
genital valve.3 
Chitinized patches large.6 
