Timms: A revision of Limnadopsis clam shrimps 
63 
Head (Fig. 11B) with pyriform frontal organ placed 
posteriorly and protruding a little farther than eye mound. 
Anteriorside of eye mound and rostrum meeting at about 
120°, junction angular. Rostrum protruding with almost 
parallel dorsal and ventral edges and downward curving 
apex. Naupliar eye triangular with largest surface ventral. 
First antenna subequal in length to peduncle of second 
antenna and having about six lobules. Second antenna with 
peduncle of 12 apparent segments and two flagella of about 
20 flagellomeres each. Most second antennal segments, par¬ 
ticularly in the region of each flagellum, bearing 3-5 spines 
anteriorly (Fig. 11D). 
Trunk segments usually 26, each bearing pair of thoraco- 
pods, these decreasing in size posteriorly and with anterior 
two pairs modified as claspers. Posterodorsally each segment 
with large, rounded protuberance, this bearing 5-7 large 
spines on last five segments, many setae on next 5 segments 
anterior to these, and 1-3 setae on most other segments. 
Claspers of normal structure for Limnadopsis, with single 
spine apically on movable finger. 
Telson (Fig. 11C) with about 15 spines in each dorsal 
row, largely saw-tooth in appearance, i.e. shaped like 
isosceles triangles, but first two narrower, first a little longer 
than second. Two telsonic setae inserted on protuberance 
situated about one fifth of way along dorsal side of telson. 
Caudal claws about 9-10 times longer than wide, fairly 
evenly curved ventrally and bearing about 14-18 setae me- 
diodorsally, followed by about 6 short spines dorsally and 
numerous denticles on the markedly curved apical quarter 
of claw. First one or two spines sometimes arising between 
last few setae. 
Female. Largely similar to male, except in carapace shape 
(Fig. 11E), rostrum shape (Fig. 11F), and lack of claspers. 
Dorsal margin of carapace evenly arched, almost smooth. 
Dorsoanterior angle distinct, about 110°, dorsoposterior 
angle as in male, but not so marked. Umbo as in male. 
Anteroventral area of carapace more convex than in male, 
while posteroventral area also expanded as in male but 
more posteriorly than ventrally, thus giving an appearance 
of greater posterior expansion than in male. Growth lines 
as in male. 
Head (Fig. 11F) with proportionally smaller eye than in 
male, and thus with pyriform frontal organ protruding more 
dorsally than in male. Rostrum short, almost in form of 
isosceles triangle, with rounded apex. Naupliar eye triangular 
and occupying about half of rostrum. 
Eggs (Fig. 5C) most unusually shaped and structured; 
somewhat bell-shaped, about 240 pm high and about 220 pm 
in diameter (range 236-242 pm high, 218-223 in diameter, 
n = 5), with about 7 (6 around the circumference and one 
ventrally) large grooves separated by unevenly developed 
sharp ridges, some of latter meeting at top in distinct point. 
Each groove containing smooth, weakly developed subsidi¬ 
ary ridge. 
Variability. Specimens from Broome are a little different 
from the type lot. The carapace tends to be slightly larger at 
11-12 mm by 7-8 mm, but the unusual shape is the same 
as in males and females from Kimberley. The dorsal margin 
is more irregular than in the Kimberley specimens, but still 
basically smooth. There are only 25 growth lines, with nearly 
20 of these distinct and well spaced and 4-6 situated margin¬ 
ally and closely spaced; therefore they do at least feature the 
same unusual arrangement of many well-spaced lines and a 
few tightly-spaced lines. The first antennae have 7 lobules 
and the second antenna 18 flagellomeres, both figures being 
slightly different from the type lot. The telson also armed 
differently: 16-18 dorsal spines with the first one 1.5 times 
larger than the rest, and caudal claw with about 15 long setae 
and 4-5 spines two-thirds of the way along its length. 
Comments. This species is distinctive by reason of its 
carapace shape and its possession of numerous growth lines 
arranged in two groups about 20 normally spaced lines and 
4-10 marginal lines spaced very closely together. It has 
many (ca 5-6) spines midlength on the cercopods, as do 
L. parvispinus, L. occidentals and L. minuta, but is easily 
distinguished from these species by its unique carapace 
as mentioned above, and in contrast to L. parvispinus and 
L. occidentalis, by the well expressed growth lines (as 
opposed to faint lines), and 1-2 fewer spines on the middle 
flagellomeres. Features distinguishing it from L. minuta 
are noted above. 
Limnadopsis occidentalis n.sp. 
Figs. 2F, 5J, 12 
Types. Holotype 8 WAM C39336, allotype $ WAM 
C39337, paratypes, 28,29, WAM C39338. Type locality: 
Western Australia, N of Carnarvon, Boolathana Station, 
unnamed claypan, 24°38'34"S 113°59'35"E, 15.iii.1995, 
S.A. Halse. 
Other material: Western Australia: 28, 8$, 58.6 km 
south of Roebourne, small pools adjacent to creek, 20°48'S 
117° 6'E, 25.vi.1964, C. Pugh, AM P55651; 18, 131 mile 
post, road to Port Headland via Woodstock, waterhole, 
21°12'S 118°48'E, 26.vi.1964, C. Pugh, AM P55650; 68, 
2 9, E of Kalbarri, Coolcalalaya Station, unnamed clay pan, 
27°31'29"S 115°05T4"E, S.A. Halse, 15.iii.1995, WAM 
C39339; c. 40 km south of Mullewa, Tardan, Christian 
Brothers College, dam, 28°43'S 115°49'E, 25.vii.1999, J. 
McRae & A. Pinder, DEC, Woodvale, SPS185; 1$, via 
Laverton, 20 km west near highway, samphire swamp, 
28°36'S 122°13'E, 17.ii.2003, B. Datson, WAM C39340. 
Habitat and distribution. Limnadopsis occidentalis lives in 
a variety of temporary fresh waters, including claypans and 
floodplain pools, all in northwestern Western Australia. 
Etymology. The species name is derived from the Latin 
occidens referring to the direction of the setting sun, and 
hence “west” an appropriate epithet for a species found in 
the west of Australia as opposed to its closely related species 
L. parvispinus, which is found in eastern Australia. 
Male. Carapace (Fig. 12A) oval, 11 mm by 6 mm, L:D ratio 
= 1.8. Dorsal margin weakly convex with highest point at 
about one-third length, slight depression anterior to umbo 
and distinct dorsoposterior angle. Dorsal margin almost 
smooth, but with slight serrations at many growth lines, 
mainly posteriorly. Growth lines 11, weakly expressed. 
Carapace weakly granulated within, but presenting a smooth 
yellow-buff surface in preserved condition. 
