60 
Records of the Australian Museum (2009) Vol. 61 
midway on the anterior edge of hand. Third thoracopod (Fig. 
4C) similar in structure to that of L. birchii. Proportions of 
endites, endopod, exopod and epipodite slightly different, 
and significantly palp of fifth endite slightly shorter than 
fifth endite and epipodite proportionally larger. Other tho- 
racopods of same basic structure, but without palp and with 
even larger epipodite. 
Telson (Fig. 8C) with 18 dorsal spines in each row. Most 
anterior spine about 1.25 t im es larger than next few. Most 
spines subequal in size and evenly spaced, though most 
posterior ones smaller and crowded on fixed telsonic claw. 
Two telsonic setae inserted on protuberance situated about 
one quarter of way along dorsal margin of telson. Caudal 
claws about 8-10 times longer than wide, with long, almost 
straight basal section of fairly even width and much shorter, 
curved apical part narrowing to sharp apex. Basally each 
caudal claw bearing about 15 setae mediodorsally, most 
slightly longer than width of claw, followed by about 6 
short spines almost dorsally, last of these being largest. First 
few spines sometimes arising from between last few setae. 
Curved apical part beyond last spine bearing many short 
denticles dorsally. 
Female. Carapace (Fig. 8D) similar to that of male, but 
more compact (length 13-14 mm, height 9-9.5 mm) and 
with more convex dorsal and ventral margins. Depression 
anterior to umbo hardly present or not at all. Growth lines 
10-11, weakly expressed. 
Rostrum (Fig. 8E) a shorter isosceles triangle than in 
males, with basal width just greater than length. Apex 
rounded. First and second antennae as in male, but some of 
syntypes with one fewer lobe on first antennae. 
Remainder of animal similar to male, except for tendency 
to have more spines (up to 10) on cercopods, with many of 
these spines mixed with last few setae. 
Eggs variable (Figs. 5G,H). Most populations with eggs 
shaped like subconical cylinders (i.e. cupcake- or muffin¬ 
shaped) about 170 pm in diameter and height (range 168-174 
pm, n = 6). Sloping sides with 16-20 parallel grooves, with 
narrow ridge within each groove, and low, wide ridges 
between, all generally sloping at about 30° from vertical 
axis of egg. Outer cortex with more included bubbles than 
in other species of Limnadopsis. Base generally with 2-4 
parallel grooves on overall flat surface, but sometimes 
grooves crescent-shaped and not parallel. Dome of egg with 
many (4-8) grooves in parallel and grouped; highest point 
often off centre of vertical axis of egg. Occasionally (as in 
specimens from Fat Hen Lake), ridges between grooves 
possessing many included bubbles and dome lacking, thus 
egg is more cylindrical, and number of grooves on sides 
reduced to 10-12. 
Variability. Limnadopsis parvispinus is a particularly 
variable species (cf. Figs. 8, 9). The carapace shape is 
reasonably standard, except for the difference in shape 
between males and females, but the number of growth lines 
in apparently mature specimens and their expression is quite 
variable. Generally there are about 12-15 growth lines, 
which are scarcely visible except near the dorsal margin. 
Populations with 10-12 lines occur in the Paroo, and there 
are 15-18 readily visible lines in individuals from Bollon. 
Henry (1924) gave the range as 12-14 lines, and all “well 
marked.” Individual specimens are generally transparent and 
yellowish green (Henry, 1924), although those from Bollon 
are brown, especially near the dorsal margin. 
While there is a consistent distinct difference in rostrum 
shape between males and females, in both sexes it is variable. 
In males, it may be rectangular or pointed, longer (length 
2 twice depth) or shorter (length = depth), and the apex is 
sometimes curved ventrally. In females, it is always short 
and shaped like an isosceles triangle, but the height of the 
triangle is variable. The naupliar eye is always positioned 
near the base of the rostrum, but its orientation is variable, 
two common positions being aligned with the axis of the 
rostrum or with the base at a 45-60° angle to the rostrum 
axis. The population from Buster’s Black Box Swamp, 
Queensland, had intersex “males” with a short rostrum and 
small claspers and no ordinary males. 
The length of the first antenna is generally subequal to 
that of the peduncle of the second antenna, but in males it is 
slightly longer and has more lobes than in females. In males 
the lobes number 7-10, typically about 9, while in females 
the range is 7-9, with a mean of about 8. The peduncle of 
the second antenna typically has 12 apparent segments, 
while the number of flagellomeres varies from 14-21, often 
about 18. 
Trunk segments generally number 25, but occasional 
specimens have 26. Posterodorsal thoracic armature in both 
sexes involves about the 6-7 most posterior segments each 
with 1-3 dorsal spines on a small protuberance, preceded 
by 6-7 segments with long hair-setae on similar protuber¬ 
ances, these decreasing in number and size anteriorly from 
many long setae per segment to 1-2 short setae per segment. 
The claspers are of standard structure for Limnadopsis, with 
the only variability noted in the spines tipping the movable 
finger; they are relatively small (cf. the spine in L. tatei) and 
number 1-3. 
On the telson the most anterior dorsal spine in each row 
ranges from 1.25 times the size of the next few spines (in 
the syntypes) to otherwise about 1.5 times the size of the 
next few spines (in most specimens). Telsonic spines vary 
between 16 and 22 in number and are usually subequal in 
size and spacing, but uncommonly may be variable in both 
features. Almost always a few are placed on the ascending 
limb of the large, posterior, fixed telsonic claw. Although the 
caudal claws are generally long and thin (8-10 t im es longer 
than wide) with a long, straight, proximal section bearing 
the setae and spines, other proportions occur. The setae on 
the basal half of the caudal claws vary between 8 and 15 in 
number and generally are relatively short, particularly the 
last few, which often overlap with dorsal spines, situated at 
half to two-thirds the length of the caudal claws. These spines 
number 4-10 (often c. 6), with the most posterior the thickest, 
but not necessarily the longest. There are always many fine 
denticles on the dorsal surface of the curved, tapering apical 
part of the claw. 
