242 
H. Smit 
National Park, Northern Territory, Australia, 25 
July 1994 (NTM). 
Paratypes 
Australia: Northern Territory: 2 <J, 6 2, same 
data as holotype (NTM); 2 <J, Lily Ponds Falls, 
Katherine Gorge National Park, 27 July 1994 
(ZMA); 1 6 (WAM), 4 2 (WAM, ZMA), Plunge 
Pool, Edith Falls, Katherine Gorge National Park, 
30 July 1994. 
Diagnosis 
PII with patch of setae; body dorsally with short 
projection (rostrum). Cauda of male rounded and 
slightly enlarged posteriorly; posterior margin of 
cauda with a small, irregular shaped hyaline area. 
Female with short and broad genital plates, sloping 
posteriorly. 
Description 
Male 
Body 902 (854-1028) long and 475 (466-524) 
wide. Body colour blue. Anterior body margin 
straight. Anterior end of body dorsally with a short 
projection (rostrum). Dorsal shield incomplete, 
dorsal furrow extending onto lateral sides of body. 
D1 on small humps (Figure 27). Cauda well 
developed, 330 long, posterior part slightly 
enlarged, posterior margin rounded (Figure 26). 
Posterior margin of cauda with a small, irregular 
shaped hyaline area. Gonopore 58 long. Genital 
plates short, anterior and posterior margins 
rounded, extending to lateral body margin (Figure 
25). Petiole present, dagger-like; one of the 
paratypes has a double petiole. Lengths of PI-PV: 
29, 62, 35, 69, 26; PII with a patch of setae (Figure 
28). Lengths of I-leg-4-6: 114, 126, 116. Lengths of 
IV-leg-4-6: 155, 136, 165; IV-leg-4 with a short, 
truncated spur. 
Female 
Body 863 (728-883) long and 698 (611-737) wide. 
Body slender to broad egg-shaped, posterolateral 
comers absent or present. Anterior body margin 
rounded, rostrum short. D1 not on humps. Dorsal 
shield complete, 427-504 long. Medial margin of 
CX4 larger than medial margin of CX3. Medial 
distance of CX4 about as large as width of one 
genital valve. Gonopore 126 long; genital valves 
without chitinous patches. Genital plates short and 
broad, sloping posteriorly (Figure 29). Lengths of 
PI-PV: 29, 73, 36, 52, 34; palp as in male. Lengths 
of I-leg-4-6: 116, 126, 97. Lengths of IV-leg-4-6: 165, 
175, 165. 
Remarks 
A small number of species of the subgenus 
Megaluracanis have been described from Australia. 
Most closely related are A. margatelhis Cook, which 
differs from the new species in medial projection at 
the posterior margin of the cauda, and A. cheetus 
Cook, which has a different petiole. The female is 
very close to A. thienemanni K.O. Viets. The dorsal 
shield of caeruleus is smaller, the ratio of body 
length/length of dorsal shield is 1.58-1.70 for 
caeruleus and 1.39-1.48 for thienemanni. Further, A. 
caeruleus does not have the large anterior seta on 
the dorsal margin of PIV. Like thienemanni, females 
of caeruleus are variable in body shape. 
Etymology 
The species is named for its conspicuous blue 
colour. 
Arrenurus (Megaluracarus) gilvus sp. nov. 
Figures 30-34 
Material Examined 
Holotype 
<5, Lily Ponds Falls, Katherine Gorge National 
Park, Northern Territory, Australia, 27 July 1994 
(NTM). 
Paratypes 
Australia: Northern Territory: 1 2, same data as 
holotype (NTM); 1 6, Southern Rockhole, 
Katherine Gorge National Park, 27 July 1994 
(ZMA). 
Diagnosis 
Body colour yellowish, body dorsally with small 
rostrum. PII with large patch of setae. Cauda of 
male posteriorly widened, with straight to slightly 
concave posterior margin; posterodorsally on 
cauda two peg-like setae; posterior margin of 
cauda with small hyaline area. Female with short, 
broad, posteriorly sloping genital plates. 
Description 
Male 
Body 1048 (1004) long and 524 (495) wide. Body 
colour yellowish. Anterior body margin rounded, 
near anterior margin a small rostrum. D1 on small 
humps (Figure 32). Postocularia and associated 
setae of D2 very long. Cauda well developed, 
longer than wide, posteriorly widened, posterior 
margin of cauda straight to slightly concave (Figure 
31). Dorsally on cauda, near posterior margin two 
rounded peg-like setae; posterior margin of cauda 
with a very small hyaline area. Genital plates short 
and broad, extending to lateral body margin 
(Figure 30). Lengths of PI-PV: 29, 65, 35, 68, 23; PII 
with large patch of setae on a bulge (Figure 33). 
