50 
Records of the Australian Museum (2009) Vol. 61 
Material and methods 
Collections of Limnadopsis were examined in the Australian 
Museum, Sydney (AM), Queensland Museum, Brisbane 
(QM), South Australian Museum, Adelaide (SAM), National 
Museum of Victoria, Melbourne (NMV), Western Australian 
Museum, Perth (WAM), Museum and Art Gallery of the 
Northern Territory, Darwin (MAGNT), the corporate 
collections of staff of the Department of Conservation, 
Western Australia (DEC), and the personal collections of 
M.C. Geddes and the author. Information on collections 
is not uniform, especially for older material in museums. 
Measurements were made using a stereomicroscope and 
a template placed under the specimens and marked in half 
millimetres (accurate to ±0.25 mm). Drawings of whole 
animals, heads, and telsons were made with the aid of an 
ocular drawing tube. For further information on collections 
by the author from the Paroo region (Currawinya National 
Park; Bloodwood, Muella, Rockwell and Tredega Stations) 
see Timms & Richter (2002). Some inf ormation on collec¬ 
tions by DEC is available in Halse et al. (2000) and Pinder 
etal. (2004). 
Various authors (e.g., McLaughlin, 1980) have used many 
terms to describe the features of clam shrimps. For general 
body parts, I follow Richter & Timms (2005), except I use 
caudal claws (rather than caudal furcae) and for the claspers 
I follow Olesen et al. (1996). 
Fig. 1. General view of Limnadopsis pilbarensis n.sp. Drawn by 
Jane McRae. 
Systematics 
Subphylum Crustacea Briinnich, 1772 
Class Branchiopoda Latreille, 1817 
Order Diplostraca Gerstaecker, 1866 
Suborder Spinicaudata Linder, 1945 
Family Limnadiidae Baird, 1849 
Genus Limnadopsis Spencer & Hall, 1896 
Diagnosis. Umbo poorly developed, but present; carapace 
with many well expressed growth lines; growth lines in some 
species projecting as carinae along dorsal margin of carapace; 
head with a frontal organ on the apex of a posteriorly situated 
pyriform appendage; first antennae bar-shaped bearing 
many (5-13) lobes; 24-32 pairs of thoracopods; male with 
anterior-most two pairs of thoracopods modified as claspers, 
with the movable finger terminating in 1-3 spines, instead 
of a suctorial organ as in other limnadiids. First spine of the 
dorsal spine row of the telson large and protruding from the 
general alignment of the telson’s dorsal surface. 
Remarks 
In the original diagnosis by Spencer & Hall (1896), emphasis 
was placed on the 10-15 clearly marked growth lines, the 
“dorsal line, which is raised into a much-compressed spiney 
keel”, and the large number (26-32 pairs) of limbs. Henry 
(1924) and Daday (1925) continued in this vein, oblivious 
to the virtual lack of spiny outgrowths (i.e. carinae) and 
the large number (ca 30) of growth lines in L. brunneus. 
Likewise Novojilov (1958) was most impressed by the 
spiny dorsal outgrowths, so much so that he erected the 
subfamily Limnadopsinae based on this character, containing 
Limnadopsis and his Limnadiopsium. Straskraba (1965a), and 
Thiery (1996) followed Novojilov (1958) in their definitions 
of the subfamily Limnadopsinae, using the spiny outgrowths 
as their only diagnostic feature. Given that in L. brunneus, 
L. parvispinus , and five new species described below, these 
spiny outgrowths are absent or minimally expressed, this 
character cannot be used alone as a major distinguishing 
feature of Limnadopsis or the subfamily. 
Many of the other characters mentioned in the diagnosis 
are also not unique to Limnadopsis, or are not universal in 
the genus. However, all species of Limnadopsis have the 
first spine of the dorsal spine row of the telson large and 
protruding from the general alignment of the telson’s dorsal 
surface. All species also have, well-expressed lines of growth 
on the carapace. However in L. parvispinus the lines are less 
well expressed than in other species, but still quite different 
from the few poorly expressed lines that are typical for the 
remainder of the Limnadiidae, except in Metalimnadia 
(Straskraba, 1965a). Metalimnadia differs from Limnadopsis 
in lacking a frontal organ, in having a well-developed umbo, 
