Records of the Western Australian Museum 17: 395-409 (1996). 
Two new species of anchialine amphipod (Crustacea: Hadziidae: 
Liagoceradocus) from Western Australia 
J.H. Bradbury and W.D. Williams 
Department of Zoology, University of Adelaide, South Australia 5005, Australia 
Abstract - Two new species of Liagoceradocus, L. subthalassicus and L. 
branchialis, from anchialine habitats (hypogean waters of marine origin) are 
described from Barrow Island and North West Cape, Western Australia. 
INTRODUCTION 
It is becoming clear that the systematic boundary 
between amphipods inhabiting epicontinental 
waters and coastal marine waters in Australia is 
indistinct. Whilst there are many species in genera 
and families confined to or characteristic of inland 
fresh waters, there are also many species which, 
though found in Australian fresh waters, belong to 
genera or families of typically marine habit or 
which display many taxonomic features linking 
them with marine ancestors (see, for example 
Barnard and Williams 1995). The occurrence in 
Australia of undoubted marine forms in waters of 
essentially oceanic origin located inland but at no 
great distance from the coast is not therefore 
unexpected. The problem, however, is how best to 
treat them in revisions of the Australian amphipod 
fauna: as epicontinental species, or marine species 
srnsu stricto? In the event it has been considered 
best to treat them separately and not to regard 
them as an integral part of the Australian inland 
aquatic amphipod fauna. 
In recent collections from anchialine sites on 
Barrow Island (20°46'S, 115°24'E), and North West 
Cape (22°25'S, 113°46'E), Western Australia, we 
located specimens of the marine genus 
Liagoceradocus. Description of these specimens form 
the basis of this paper, and the new species 
described herein (L. subthalassicus and L. branchialis) 
are not regarded as members of the amphipod 
fauna of Australian inland waters. For this reason 
they are not included in our series of papers 
reviewing this fauna, but dealt with separately. 
Methods of description follow those of Williams 
and Barnard (1988) except that L represents left 
and R, right. All specimens are lodged in the 
Western Australian Museum, Perth (WAM). 
Genus Liagoceradocus Barnard 
Liagoceradocus Barnard, 1965: 504. 
Remarks 
The genus Liagoceradocus Barnard, 1965 was 
erected for a pair of specimens taken from Ifaluk 
Atoll, Caroline Islands. Six species have so far been 
assigned to the genus, all from interstitial and 
subterranean marine waters of the tropical Pacific 
ocean. Ronde-Broekhuizen and Stock (1987) 
considered Liagoceradocus a viable genus distinct 
from Hadzia, whereas Stock and Iliffe (1991) 
considered it a doubtful genus because of the poor 
initial description of the type, and poor condition 
of the types. Stock and Iliffe (1991) questioned the 
assignation of other species to the genus on the 
grounds of the unique maxillipedal palp and 
distinct, spine-less palm of the second gnathopod 
of Liagoceradocus pusillus Barnard 1965. Barnard 
(1977), when assigning a second species to the 
genus, reduced the status of Liagoceradocus to a 
subgenus of Hadzia, although the genus was 
maintained by Barnard and Barnard (1983). 
Nevertheless, subsequent species have been 
attributed to Liagoceradocus. Stock and Iliffe (1991) 
themselves added a further two species despite the 
concerns expressed above. Furthermore, they 
noted that sexual dimorphism of the third pleopod 
was evident in some species while absent from 
others (although they suggested this may have 
been a reflection of lack of adult males among 
collections, whilst in some descriptions pleopods 
were not fully described). However, inconsistency 
of sexual dimorphism has not necessarily been 
regarded as contrary to generic compatability. 
Williams and Barnard (1988) reported species of 
Neotiiphargus may or may not display sexual 
