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Records of the Australian Museum (2009) Vol. 61 
large as the others and curving slightly posteriorly; last 2-3 
spines on curved, telsonic claw; this claw curved anteriorly 
and more than twice as long as basal width.Two telsonic 
setae inserted on protuberance about one quarter the way 
along dorsal surface of telson. Caudal claws well developed, 
at least twice as large as telsonic claw and curved concavely 
forward. Basal half thick, almost straight, and bearing about 
10 shortish setae mesodorsally. Two short spines located 
about two thirds of way along each caudal claw on dorsal 
surface, followed by row of many denticles situated dorsally 
on pointed apex of caudal claw. 
Female. Carapace (Fig. 14E) 10 mm by 6 mm. Similar to 
that of male, but hinge line slightly more curved. 
Head (Fig. 14F) similar to that of male, but rostrum short, 
about as long as deep, and blunt. Naupliar eye of about same 
size and position as in male, occupying much of rostrum. 
First antennae shorter than in male, with about 6 unequal 
lobes and generally no basal spine. Second antenna as in 
male, but generally with only about 12 beaded flagellomeres, 
rarely a few more to a miximum of 15. 
Number of body segments, posterodorsal armature, and 
telson similar to those in male. 
Eggs (Figs. 5F, 14G) subspherical, about 250 pm in 
diameter (range 247-252 pm, n = 5). Surface very irregular 
with deep conical pits (n = c. 20) bordered by thin, expressed 
ridges. Where three ridges meet, surface is further expressed 
as spines visible in light microscopy. 
Comments. Limnadopsis pilbarensis is most similar to L. 
tatei. Many features of L. pilbarensis lie within the range of 
variability seen in L. tatei , including valve size, number of 
growth lines, rostrum shape and relative size, first antenna 
lobe number, number of flagellomeres of second antenna, 
number of body segments, gross structure of claspers, and 
many features of the telson. However L. pilbarensis is dis¬ 
tinctive in its carapace structure: (a) it lacks dorsal carinae, 
although the dorsal margin is humped where the growth lines 
meet it, ( b ) in males the dorsal margin is always markedly 
curved whereas in L. tatei it is weakly curved or straight, 
(c) carapace tends to be ballooned in L. pilbarensis but 
flatfish in L. tatei , and (d) the growth lines in L. pilbarensis 
are particularly clearly visible, being well expressed and 
generally coloured brown to black on a yellowish carapace 
background. The dorsal telsonic spines are also different in 
the two species: although there are similar in number, those 
in L pilbarensis are subequal and fairly evenly spaced, while 
in L. tatei they vary much in size and spacing. Also, the an- 
teriormost spine is about 1.5 times the size of the others in 
L. pilbarensis and 2 times or greater in L. tatei. 
Limandopsis pilbarensis cannot be confused with the 
other species of Limnadopsis besides L. tatei. It is easily 
distinguished from L. birchii by the much smaller size, 
fewer body segments, significantly fewer telsonic spines and 
lack of carinae on the carapace. Though similarly lacking 
carapace carinae, L. parvispinus is a little larger (> 12 mm) 
and significantly has more (>13) telsonic spines and more 
(>11) growth lines than L. pilbarensis. Furthermore, the 
carapace in L. parvispinus is expanded posteriorly beyond 
the dorsoposterior corner, but not in L. pilbarensis. Among 
limnadiids and possibly most Australian branchiopods, the 
eggs are particularly distinctive with their conical pits and 
spinous outgrowths. 
Limnadopsis brunneus Spencer & Hall, 1896, 
nomen dubium 
Limnadopsis brunneus Spencer & Hall, 1896: 243, pi. 23, 
figs. 28-29; Sayce, 1903: 250; Wolf, 1911: 254 (list); 
Dakin, 1914: 295 (list); Henry, 1924:122 (list), 132 (key); 
Brtek, 1997: 58 (list). 
Limnadiopsis brunneus. —Daday, 1925: 183-184, fig. 124 
(misspelling of genus name); Schneider & Sissom, 1982: 
72-73 (misspelling of genus name). 
Types. None designated, though the four dried specimens 
used to erect this species (Spencer & Hall 1896) would be 
syntypes, but they are missing. Type locality: Knuckeys 
Fagoon, Darwin, NT. 
Comments. Spencer & Hall (1896) erected this species, 
noting only that the carapace carinae were not as strongly 
developed as in L. tatei , and that there were 30-34 growth 
lines. Their diagram shows only 20 growth lines, and 
virtually no dorsal carinae. Immediately this presents a major 
problem, as the diagram and brief description do not match. 
No specimens are available in any Australian Museum, 
although Schneider & Sissom (1982) claimed to have found 
this species in the Kimberley. These specimens are now lost 
(S. Sissom, pers. comm.) and there is doubt over their identity 
based on their description of only 20 growth lines (see 
Richter & Timms, 2005). The author visited the type locality 
in the wet season (late February, 2007) and was unable to 
find any specimens, nor later raise any Limnadopsis from 
dried mud collected from the site. As a further complication, 
it is just possible the presently described L. multilineata is 
in fact L. brunneus, based on the written description of the 
latter. Similarly, and based only on Spencer & Hall’s (1896) 
diagram, the present L. minuta could be in fact L. brunneus. 
Hence the animal remains an enigma and therefore is con¬ 
sidered a nomen dubium. 
Discussion 
Variability. Spinicaudatans are notoriously variable in their 
morphological characteristics (D.C. Rogers, pers. comm.). 
Straskraba (1965a) noted that in the Fimnadiidae, and 
specifically in Limnadia lenticularis, the carapace shape, 
number of growth lines, dorsal extension of the growth lines, 
and numbers of telsonic spines and setae and spines on the 
caudal claw are all variable in expression. Cycizids are even 
more variable in these and other characters (Straskraba, 
1965b). The situation in Limnadopsis is no exception, with 
variation within and between populations noted particularly 
in the numbers of growth lines, telsonic spines, and spines 
of the cercopods, and to a lesser extent in carapace shape, 
and expression of dorsal carinae of the carapace. Adult size 
is also variable, but this is also influenced in spinicauda¬ 
tans by nutrition during development (D.C. Rogers, pers. 
comm.). Although the dorsal trunk spination and setation 
has been described for each species, these features are also 
variable within species, probably at least partly associated 
with predation pressure (D.C. Rogers, pers. comm.). Some 
species are more variable than others, with L. tatei being the 
most variable, and L. birchii the least variable, of those for 
which numerous specimens have been examined. 
