Two new anchialine amphipods from Western Australia 
lateral and apico-medial spines, prominent baso- 
facial spine. Rami unequal; inner ramus longer 
(90:75). Spine rows of rami reduced to a single 
dorsal spine on each, at M0.5, apices of rami each 
bearing 5 spines. Second uropod peduncle sub-equal 
in length to the shorter, outer ramus, bearing two 
dorso-medial spines at M0.4 and M0.7, a single 
dorsally displaced, sub-apical disto-lateral spine 
and 4 similarly arranged spines medially. Inner 
ramus longer than outer (77:58), outer ramus 
bearing a single row of 3 dorso-lateral spines and 4 
terminal spines, inner ramus with a row of 4 dorso- 
medial spines and 5 terminal spines. Medial 
margin of peduncle and both margins of rami 
bearing small tooth spines. Third uropod 
magniramous, dispariramous. Peduncle short 
(60:160), with a single baso-medial seta at M0.3 and 
a pair of apico-dorsal spines. Outer ramus of 2 
articles, proximal article bearing lateral and disto- 
medial marginal spines and clusters of 3 apical 
spines both laterally and medially; distal article 
shorter (35:125) with 2 medio-distal setae only. 
Inner ramus of one article, lanceolate, sub-equal in 
length to outer ramus, marginal spines evenly 
spaced, discontinuous basally on the lateral 
margin. Telson (Figure 3) 2.3x as long as wide, 2x 
urosomite 3, cleft 100%. Apices a rounded point, 
sub-apices notched bearing single medial and 
lateral short spines and 3 medial sub-marginal 
spines, 3 lateral and 2 medial spines marginal on 
each lobe. Penicillate setules absent. 
Distribution 
Barrow Island, Western Australia. 
Relationship 
Liagoceradocus subthalassicus shows some minor 
variation from the genus as originally described by 
Barnard (1965), but not from the generic 
characteristics of species assigned to the genus later 
or by Barnard and Barnard (1983). L. subthalassicus 
differs in the presence of rudimentary inner lobes 
of the lower lip, of palmar spines on the second 
gnathopod, and in having a greater number of D 
setae on the mandibular palp. 
The new species differs from L. pusillus Barnard 
in the absence of 2 dorsal spines on urosomites 1- 
2, although pleonite 4 bears 3 small setae, in the 
presence of a very weak rostrum, larger lateral 
cephalic lobes, palmar spines on the second 
gnathopod, a shorter article 1 on the mandibular 
palp and an extra seta on the second article and 9 
rather than 6 D setae of the third article, a 
degenerate molar seta, presence of small basal 
lobes to the lower lip, pubescence on the inner face 
of the inner plate of the second maxilliped, 
relatively larger and longer fifth article with a keel¬ 
like posterior lobe on the second gnathopod, 
moderate expansion of the second article of 
401 
pereopods 5-7 (on P6 this article is post-ventrally 
lobate), and the telson lacks penicillate setules. 
Liagoceradocus subthalassicus differs from L. 
lonontaka Barnard, 1977 in possessing a slightly 
oblique left palm on the first gnathopod, palmar 
spines on the second gnathopod, a shorter first 
antenna, extremely short molar seta, 9 rather than 
7 or 8 D setae on the third article of the mandibular 
palp, more slender third article of the maxillipedal 
palp which is also less spinous although facially 
pubescent with distal comb rows of setae, small 
basal inner lobes of the lower lip, and the third 
uropod more nearly magniramous. 
Liagoceradocus lobiferus Stock and Iliffe, 1991 is 
similar to L. lonomaka except for an apically 
bulbous third article of tire maxillipedal palp, more 
elongate and less lobate second article of the 
seventh pereopod. L. unciferus Stock and Iliffe, 1991 
is similar to L. lobiferus except in the form of the 
gland cone of the third article of the second 
antenna, almost symmetrical palps of the first 
maxilla, lack of spines on the first urosomite, and 
the morphology of the male endopodite of the 
third pleopod. L. subthalassicus thus differs from L. 
unciferus in the form of the gland cone, being 
similar to L. lobiferus, and the asymmetry of the 
palps of the first maxilla, and from L. lobiferus in 
lacking spines on the first urosomite, having a 
shorter third article, longer accessory flagellum and 
greater number of aesthetascs — although of shorter 
length - on the first antenna. There is a 
rudimentary molar seta, the mandibular palp third 
article is longer and bears an extra E seta, the inner 
lobe of the first maxilla is more slender and 
triangular, bearing 13 L, 12 R plumose setae, the 
outer lobe with 6 L and 7 R denticulate distal 
spines and 1 small naked medio-distal spine on 
each, the palps bearing on the left 4 slender distal 
and 2 short sub-distal spines, on the right 4 + 1 
robust spines. The outer lobe of the second maxilla 
bears many long distal setae, not, however, 
arranged in two discrete rows as in L. lobiferus, the 
inner lobe bears an oblique row of 14 setae, the 
maxillipedal palp article 3 is more slender, the 
dactyl more setate, the outer lobe of the maxilliped 
bearing two disto-medially placed, rather than five 
robust, medial spines, the medial margin is carved 
into acuminate sinuosities proximally, the left inner 
lobe with three distal, one sub-distal and one small 
sub-distal sub-marginal spines the right inner lobe 
with three distal and one sub-distal spines. The 
first gnathopod bears posteriorly on the second 
article six long apically curved setae and a single 
long straight seta, the same article of the second 
gnathopod with three long curved and two short 
setae borne on a small mid-marginal posterior keel 
like extension, the fifth article is lobate the lobe 
elongate and keel like, the setae of propodus being 
more marginal than in L. lobiferus, the palmar 
