New species of Melomys 
49 
posterior to that face; skull narrower: e.g., 
interorbital breadth 5.7 (5.6-6.0) 6 v. 6.6 (6.3-6.8) 3; 
zygomatic width 18.2 (17.2-18.9) 6 v. 20.6 (20.0- 
21.2) 2 and braincase breadth 14.9 (14.7-15.3) 6 v. 
15.4 (15.2-15.6); bulla longer 5.2 (5.1-5.3) 5 v. 4.9 
(4.7-5.0) 3, considerably more inflated; ventral 
opening of foramen oval much smaller than in 
latipes; much more deeply incised sulcus running 
anterior of the sphenorbital fissure. 
It differs from M. rubicola in having White 
cheeks, neck and back dark brown rather than 
strongly ochraceous; pes shorter 26.5 (24.8-28.1) 5 
v. 31; tail shorter 153 (142-170) 6 v. 180; skull 
approximately same length but zygomatic width 
smaller 18.2 (17.2-18.9) 6 v. 19. 
It differs from M. arcium in having White cheeks; 
tail longer rather than shorter than body length; 
tail longer 153 (142-170) 6 v. 127; skull smaller, e.g., 
condyloincisor length shorter 33.7 (32.8-35.0) 6 v. 
38.1; zygomatic width narrower 18.2 (17.2-18.8) 6 
v. 20.7; interorbital breadth narrower 5.7 (5.6-6.0) 6 
v. 6.9; nasal shorter 12.2 (11.4-13.1) 5 v. 13.7; bulla 
larger 5.2 (5.1-5.5) 6 v. 4.7, longer relative to 
condyloincisor length 0.156 (0.148-0.163) 5 v. 0.123; 
M 1 " 3 crown length smaller 6.6 (6.3-6.9) 6 v. 7.1. 
It differs from M. fiilgens in having dorsum dark 
brown and cheeks White rather than a vivid light 
orange brown (ochraceous) dorsum and no White 
cheeks; ears without whitish patch behind base; 
body length shorter 132 (118-140) 6 v. 150; tail 
shorter 153 (142-170) 6 v. 200; tail shorter relative 
to body length 1.16 (1.08-1.25) 5 v. 1.33; pes much 
shorter 26.5 (24.8-28.1) 5 v. 34; zygomatic width 
narrower 18.2 (17.2-18.9) 6 v. 22.2; interorbital 
breadth narrower 5.7 (5.6-6.0) 6 v. 7.0; palatal 
breadth narrower inside M 1 3.1 (2.8-3.4) 6 v. 3.8; 
palatal length shorter 17.9 (17.2-18.8) 6 v. 19.5; 
bulla longer relative to palatal length 0.291 (0.275- 
0.301) 5 v. 0.262; and M 1 * 3 crown length shorter 6.6 
(6.3-6.9) 6 v. 7.1. 
It differs from M. talaudium in having one hair 
per tail scale rather than three; dorsum a dark 
brown and cheeks White rather than a vivid 
ochraceous dorsum and cheeks not White; body 
and tail length shorter, approximately as for M. 
fulgens; pes shorter 26,5 (24.8-28.1) 5 v. 30.5; 
zygomatic width narrower 18.2 (17.2-18.9) 6 v. 
20.9; palate narrower inside M 1 3.1 (2.8-3.4) 6 v. 
3.9; bulla much longer relative palatal length 0.291 
(0.275-0.301) 5 v. 0.186; M 1 " 3 crown length much 
shorter 6.6 (6.3-6.9) 6 v. 7.6. 
It differs from M. caurinus in having dorsum a 
dark brown and cheeks White rather than dorsum 
orange brown (Tate 1951) and cheeks not White 
[although Rummler (1938) described the pelage 
colour of the type as affected by immersion in 
alcohol]; tail much longer relative to body length 
1.16 (1.08-1.25) 5 v. 0.8; scales on tail flat and not 
raised as round humps as in caurinus; ear much 
longer 17.8 (16.3-19.7) 6 v. 10; pes shorter 26.5 
(24.8-28.1) 5 v. 29.5; skull narrower, e.g., zygomatic 
width 18.2 (17.2-18.8) 6 v. 20.0; interorbital breadth 
5.7 (5.6-6.0) 6 v. 6.4; palatal breadth inside M 1 3.1 
(2.8-3.4) 6 v. 3.5; skull shorter, e.g., diastema length 
9.4 (8.7-10.1) 6 v. 10.6; palatal length 17.9 (17.2- 
18.8) 6 v. 20.3; bulla longer 5.2-(5.1-5.5) 6 v. 4.8, 
also longer relative to palatal length 0.291 (0.275- 
0.301) 5 v. 0.237; and M 1 ' 3 crown length much 
shorter 6.6 (6.3-6.9) 6 v. 7.8. 
The Tanimbar Melomys is difficult to confuse 
with M. rufescens from which it differs in having a 
dark brown dorsum and White cheeks rather than 
a generally brightly coloured Cinnamon dorsum 
(except for M. r. stalkeri) with no white cheek 
patches; tail with flat scales rather than scales with 
raised granules or humps; fewer tail scales per cm 
12-14 v. 16-19; and molar row generally longer, 
>6.3 [only M. r. rufescens exceeds this but then only 
occasionally 6.1 (5.5-6.5) 25 (from Rummler 1938)]. 
Comparison with a series of M. rufescens from the 
nearest population to Yamdena Island (Wokam 
Island, Aru group) indicates that M. cooperae also 
differs from this form by having a narrower 
rostrum; incisor more opisthodont; anterior palatal 
foramen larger; bulla longer and more inflated, 
least interorbital breadth larger; and temporal 
ridges less pronounced. 
Etymology 
Named after Mrs Norah Cooper in recognition of 
her work in the mammal section of the Western 
Australian Museum. In particular for her support 
and contribution to the Indonesian project between 
1987-1993, where she participated in the Sumba 
Island expedition. 
OTHER SPECIMENS EXAMINED 
Melomys leucogaster latipes 
Australian Museum No. (AM) M13781, A 2, skin 
and skull, Naiya Village, E. side Mt Karimui, S. 
Simbu Province, Papua New Guinea; AM 13815, 
Ad, skin and skull, 2.5 km SSW Yuro Village, E. 
side Mt Karimui, S. Simbu Province, Papua New 
Guinea. 
Melomys rufescens 
Western Australian Museum No. (WAM) 
M42626-7, M42637, M42446, M42450, M42566, 
4dd 2$ 2, Kampung Karangguli, Wokam Island, 
Aru Group., Indonesia. 
ACKNOWLEDGEMENTS 
We are grateful for the support of both Mr J.L. 
Bannister, Director of the Western Australian 
