246 
H. Smit 
in the holotype. Body 926-1193 long and 369-524 
width. Genital plates short and broad, extending 
almost to lateral body margin. Posterior margin of 
cauda in specimens from Waterfall Creek and Lake 
Jabiru have a hyaline area (see Figure 42), which is 
also present in the holotype. The cauda of males 
from Waterfall Creek and Lake Jabiru is in lateral 
view less upturned than in specimens from other 
localities. 
Female 
Body 878 (708-844) long and 737 (533-655) wide. 
The genital plate is large, short and rounded, 
sloping posterolaterally. The body shape is broad 
egg-shaped to slender egg-shaped. Body with 
indistinct to very distinct posterolateral corners. 
Dorsal shield 470-592. Medial margin of CX4 
larger than medial margin of CX3. Medial distance 
of CX4 less than width of one genital valve. 
Gonopore 116 long. Palp as in male. 
Remarks 
K.O. Viets (1984) described this species from 
Northern Territory, but examination of the 
holotype revealed that his description is inaccurate 
in some aspects for the male. The females found in 
this study are quite different from the one 
described by Viets. Examination of the paratype 
females showed, that the female illustrated by Viets 
(slide 7448) has slightly larger genital plates, while 
the female of slide 7449 has much larger genital 
plates, and is similar to the females of this study. 
Below I will give some additional characters for 
the male and for the female. 
A. thienemanni is a highly variable species. The 
variation in size is large, in males as well as in 
females. Further, the shape of the cauda of the 
males and the body shape of the females is 
variable. As all specimens of this study have the 
large anterior seta on the dorsal margin of PIV, an 
unusual character in the genus Arrenurus, I 
assigned all to A. thienemanni. The related A. 
rostratus is known to be highly variable as well, 
especially in the shape of the cauda (Walter 1929). 
Arrenurus (Megaluracarus) rostratus degeneratus 
K.O. Viets 
Arrenurus rostratus degeneratus K.O. Viets, 1984: 434. 
Material Examined 
Australia: Northern Territory: 5 S, Lake Jabiru, 
Jabiru, 20 July 1994 (ZMA). 
Remarks 
This subspecies is only known from the Northern 
Territory. The body length of the males from this 
study varies between 1004 and 1038, the body 
width varies between 417 and 427. The holotype a 
is larger, the body length is 1214 and the body 
width 482 (K.O. Viets 1984). 
Arrenurus (Megaluracarus) vanderpalae Smit 
Figures 45-46 
Arrenurus vanderpalae Smit, 1992: 109. 
Material Examined 
Australia: Western Australia: 2 d, 1 9, 
Kalamina Gorge, pond near falls, Hamersley Range 
National Park, 13 August 1994 (ZMA); 15 d, 8 9, 
Jones River, E. of Roeburne, 17 August 1994 
(WAM, ZMA); 5 9, Pond Snake Creek, Millstream- 
Chichester National Park, 17 August 1994 (ZMA). 
Male 
Body 1135-1320 long, body 466-650 wide. The 
cauda shows some variation, specimens with a 
more triangular shaped cauda can be found. The 
posterior part of the cauda has in fully sclerotized 
specimens a medial extension, bordered on each 
side by a hyaline area (Figure 45), which can be 
seen from a lateral view. IV-leg-4 with a short spur. 
Female 
Body 1125 (1104-1224) long and 931 (892-931) 
wide. Body broad egg-shaped, with indistinct 
posterolateral corners. Medial distance of CX4 
about equal length of width of one genital valve. 
Posterior margin of CX4 directed transversally. 
Gonopore 155 long. Genital plates short, anterior 
margin straight and beginning halfway gonopore, 
posterior margin rounded (Figure 46). Palp as in 
male, with a patch of setae on PII lying on a bulge. 
Lengths of PI-PV: 26, 65, 50, 82, 41. Lengths of I- 
leg-4-6: 150, 146, 126. Lengths of IV-leg-4-6: 213, 
213, 179. 
Remarks 
In addition to the description by Smit (1992), 
which was based on one male only, some remarks 
will be made on the male. The female was hitherto 
unknown and is described above. 
Also see the discussion under A. gilvus sp. nov. 
Arrenurus (Micruracarus) anbangbang sp. nov. 
Figures 47-50 
Material Examined 
Holotype 
<J, Anbangbang Billabong, Kakadu National 
Park, Northern Territory, Australia, 20 July 1994 
(NTM). 
Para types 
Australia: Northern Territory: 2 i, 5 9, 1 
