Records of the Western Australian Museum 17: 235-236 (1995). 
Short communication 
First record of the false catshark, Pseudotriakis microdon, 
from Australian seas 
Gerald R. Allen and Mark A. Cowan 
Department of Aquatic Zoology, Western Australian Museum, Francis Street, Perth, 
Western Australia 6000 
The shark family Pseudotriakidae is distributed 
worldwide, mainly in deep waters of continental 
slopes. Two species were formerly recognised, but 
Compagno (1984) placed the Indo-Pacific 
Pseudotriakis aerates Jordan and Snyder, 1904 in the 
synonymy of the Atlantic P. microdon Capello, 1868. 
The known distribution of P. microdon consists of 
widely scattered, mainly Northern Hemisphere 
locations, including off the northeastern United 
States, Iceland, France, Portugal, Madeira, Azores, 
Senegal, Cape Verde Islands, Japan, Taiwan, and 
the Hawaiian Islands. Prior to the first Australian 
record reported below, the only locations in the 
Southern Hemisphere were New Zealand and the 
Aldabra Islands group, just north of Madagascar. 
Most of the specimens taken thus far were 
captured by deep-set longlines or occasionally by 
bottom trawlers. Depth of capture ranged between 
200 and 1500 metres. 
The first Australian record reported herein was 
captured on 10 August 1994 by the South 
Australian trawler “Lucky S". It was fishing for 
orange roughy (Hoplostethus atlanticus ) on the 
continental shelf in the extreme southwestern 
comer of Australia off Cape Leeuwin (approxi¬ 
mately 35°00'S, 114°45’E). Depth of capture was 830 
m and a bottom temperature of 6° C was recorded. 
The trawler's crew did not recognise the unusual 
catch and it was taken back to Albany. Fortunately, 
Mr Mike Jones, of Allerton Bait Supplies, notified 
the Albany Residency Museum. Val Milne, Head 
Curator of the institution, arranged to have it 
frozen and shipped to the Western Australian 
Museum in Perth. 
The shark was photographed, preserved in 
formalin, and is now lodged in the collection of the 
Western Australian Museum (registration number 
P.30826-001). 
Compagno (1984, part 2) provided diagnostic 
information, an outline drawing, and a brief 
summary of the biology of P. microdon. In part 1 of 
this same work he gave detailed illustrations of the 
measurements and explained the terminology 
which is used in the following paragraph. 
The following measurements (in cm) were 
recorded when the specimen was freshly thawed: 
total length 200.0; precaudal length 174.0; prenarial 
length 10.7; preoral length 10.1; preorbital length 
14.5; prespiracular length 22.3; prebranchial length 
34.0; head length 44.5; prepectoral length 45.5; 
prepelvic length 127.0; vent-caudal length 87.0; pre- 
first dorsal length 86.0; pre-second dorsal length 
148.0; interdorsal space 22.0; dorsal-caudal space 
8.3; pelvic-anal space 17.5; anal-caudal space 6.2; 
eye length 4.6; eye height 2.2; interorbital space 
14.0; nostril width 2.7; internarial space 10.7; 
anterior nasal flap length 0.8; mouth length 8.0; 
mouth width 23.8; first gill slit height 4.3; second 
gill slit height 4.9; third gill slit height 4.9; fourth 
gill slit height 4.8; fifth gill slit height 3.7; caudal 
peduncle height 9.6; girth 74.5; pectoral anterior 
margin 23.8; pectoral base 11.3; pectoral height 
23.8; pelvic anterior margin 14.4; pelvic base 13.8; 
pelvic height 14.4; pelvic inner margin length 7.2; 
pelvic posterior margin length 12.7; first dorsal 
anterior margin 45.0; first dorsal base 41.5; first 
dorsal height 5.8; first dorsal inner margin 4.1; 
second dorsal anterior margin 29.4; second dorsal 
base 29.0; second dorsal height 15.8; second dorsal 
inner margin 4.1; second dorsal posterior margin 
Figure 1 Pseudotriakis microdon, 200 cm TL, off Cape Leeuwin, Western Australia. 
