258 
H. Smit 
Viets, K.O. (1984). Uber Wassermilben (Acari, 
Hydrachnellae) aus Australien. Arcliiv fiir 
Hydrobiologie 101: 413-436. 
Walter, C. (1915). Les Hydracariens de la Nouvelle- 
Caledonie. In: F. Sarasin and J. Roux, Nova Caledonia. 
Forschungen in Neu-Caledonien und auf den Loyalty- 
lnseln, Zool. 2: 145-151. 
Walter, C. (1928). Zur Kenntnis der Mikrofauna von 
British Indien. Records of the Indian Museum 30: 57- 
108. 
Walter, C. (1929). Hydracarinen aus Java. Treubia 11: 
211-273. 
Wiles, P.R. (1990). Watermites (Acari - Hydrachnidia) of 
North Sulawesi. In: W. J. Knight and J. D. Holloway 
(eds.). Insects and the rain forests of South East Asia 
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* In Smit (1992) I supposed that the year of publication 
should be 1948, as the Arkiv for Zoologi 40A (2) has 
been published in that year. However, the separatum 
is dated 1947, and has apparently been published 
earlier. 
Key to the Australian Arrenurus 
Key to the subgenera (males only) 
1. With a petiole or protrusible, hyaline tube-like 
struture, usually with pygal lobes; if pygal 
lobes are absent with a distinct petiole 
extending well beyond posterior margin of 
body...2 
Without pygal lobes or without petiole 
extending beyond posterior body end.4 
2. No petiole present but instead a protrusible, 
hyaline tube-like structure (Figure 66), body 
divided in three parts (Figure 67). 
. Dividuracarus subgen. nov. 
Petiole present, body not divided in three 
parts.3 
3. Petiole with a large membranous extension, 
pygal lobes poorly developed (K. Viets 1935, 
figure 115a). Rhinophomcarus 
(Only one species known from Australia, i.e. 
Arrenurus gracilipes Piersig) 
Petiole without membranous extension, if 
pygal lobes are reduced, petiole is large and 
extending well beyond posterior end of body 
. Arrenurus 
4. Cauda long (more than 1/2 of body length), 
narrower than body and usually well set off 
from body. Megaluracarus 
Cauda short.5 
5. Cauda not set off from body, without notch. 
petiole absent. Truncaturus 
Cauda well set off from body.6 
6. Cauda short and wide, posteriorly with a 
median cleft, D1 on very large humps. 
. Brevicaudaturus subgen. nov. 
Cauda often with a notch posteriorly, small 
petiole often present but not extending 
beyond posterior body margin, D1 not on 
large humps. Micruracarus 
Key to the males of Arrenurus s.s. 
1. Petiole with bifurcated setae (Figure 21). 
. A. mantonensis sp. nov. 
Petiole without bifurcated setae.2 
2. Petiole with ligulate process...3 
Petiole without ligulate process.5 
3. Ligulate process short, not extending to 
posterior margin of petiole (Lundblad 1947, 
figure 45A), body colour reddish-brown. 
. A. australicus Lundblad 
Ligulate process long, extending to posterior 
margin of petiole, body colour blue to green 
.4 
4. Ligulate process anvil-shaped (Figure 10). 
. A. harveyi sp. nov. 
Ligulate process spoon-shaped (K. Viets 1935, 
figure 119a). A. pseudoaffinis Piersig 
5. Petiole sword-like (Figure 3) A. ensifer sp. nov. 
Petiole wider, not sword-like.6 
6. Pygal lobes very small, not extending beyond 
posterior body margin (K. Viets 1935, figure 
118). A. rouxi Walter 
Pygal lobes well developed, extending beyond 
posterior body margin...7 
7. Petiole wider than long (in dorsal view) 
(Figure 16). A. liliaceus sp. nov. 
Petiole narrower than long .. 8 
8. Petiole truncated, contracted in the middle 
(Cook 1986, figure 1628). 
. A. balladoniensis Halik 
Petiole rounded posteriorly, not contracted in 
the middle, sometimes with a small notch 
posteriorly (Cook 1986, figure 1632). 
. A. fissipetiolatus Lundblad 
Key to the males of Arrenurus (Megaluracarus) 
1. Cauda posteriorly with a rudimentary petiole 
.2 
Rudimentary petiole absent.8 
