Timms: A revision of Limnadopsis clam shrimps 
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Limnadopsis minuta n.sp. 
Figs. 2D, 5M, 10 
Types. Holotype S MAGNT Crl5704; allotype 9 
MAGNTCrl5705. Paratypes IS, 10$ MAGNTCrl5706 
and 2 S , 2 9, AM P76809. All types: Northern Territory, E of 
Kununurra (WA), Keep River National Park, c. 15°57'S and 
129°03'E, 8.ii. 1986, M.J. Tyler, M. Davies & G. Watson. 
Distribution. Known only from the type locality in the far 
west of the Northern Territory near the border with Western 
Australia. 
Etymology. This species is named for its small size. 
At just less than 10 mm, and about the size of a typical 
species of Limnadia, it is the smallest known species of 
Limnadopsis, a genus known for its relatively large size 
among spinicaudatans. 
Male. Carapace (Fig. 10A) 8.8 mm by 4.6 mm, L:D ratio 
of 1.9. Dorsal margin slightly convex and smooth, with 
only very minor carinae at posterior of the growth line and 
dorsal margin junctions. Carapace half-oval shaped with 
both ventral comers well rounded. Dorsoanterior angle and 
dorsoposterior angle both about 110° and carapace slightly 
expanded dorsoposteriorly. Umbo present but inconspicu¬ 
ous. Eighteen well expressed growth lines. Carapace surface 
minutely granular and uniformly brown in preserved 
specimens. 
Head (Fig. 10B) with pyriform frontal organ behind eye 
mound and subequal to latter in height. Anterior surface of 
head and rostrum meeting at sharp angle, c. 110°. Rostrum 
about as long as frontal surface of head, slightly down- 
turned at apex and containing triangular naupliar eye lying 
in a similar axis. First antenna a little longer than peduncle 
of second antenna with 8 lobules. Second antenna with 
peduncle of 12 apparent segments, many with numerous 
spines dorsally, and with two flagella of 18-20 flagellom- 
eres. Most flagellomeres, particularly those in middle region 
of each flagellum (Fig. 10E), with c. 4 spines on anterior 
margin, usually with 2 (rarely 3) crowded apically and with 
the proximal surface bare. 
Trunk segments 24, each bearing a pair of thoracopods, 
these decreasing in size posteriorly and the anterior two pairs 
modified as claspers. Posterior dorsal armature of 3-5 spines 
on small protuberances on about last 6 segments, many long 
setae on the 5 or so segments preceding these and a few setae 
on the next 4 or so more anterior segments. Claspers (Fig. 
10D) of normal structure for Limnadopsis, with one spine 
apically on movable finger and asymmetrical protrusion near 
the base of anterior edge of hand. 
Telson (Fig. 10C) with two rows of 17 dorsal spines, all 
sharp and varying a little in size. First spine about 1.5 times 
larger than the next few spines. Dorsal surface between 
lateral spinous rows with anterior hump on which telsonic 
setae are inserted, followed posteriorly by marked depression 
as surface generally evenly slopes to caudal claw articula¬ 
tions. Caudal claw about 8 times longer than wide, with 
long, almost straight, basal section of even width and much 
shorter, curved, apical part narrowing tosharp apex. Caudal 
claw basally with about 12-15 setae mediodorsally, most 
a little longer than its width, followed by 3-5 short spines 
inserted almost dorsally, posteriormost of these being by far 
(3x) the largest. Curved tapering apical part bearing many 
short denticles dorsally. Ventroposterior corner of telson with 
a spinous projection. 
Female. Very similar to male. Carapace slightly larger, 9.2 
mm by 5.1 mm, F:D ratio of 1.86, dorsal margin slightly 
curved. Head (Fig. 10F) with typical short rostrum of female 
Limnadopsis. First antenna with 6 lobules. Telson (Fig. 10G) 
as in male and both the features peculiar to this species: de¬ 
pression in the dorsal surface posterior to telsonic filament 
mound, and spiniform projection at ventroposterior corner. 
Eggs (Fig. 45K) rounded polyhedral, about 160 pm in 
diameter (range 153-168 pm; n = 5). Each surface of polyhe¬ 
dron consisting of 1-3 oval grooves, each groove containing 
low longitudinal ridge internally and surrounded by high, 
Fig. 10. Limnadopsis minuta n.sp., Keep River National Park, NT. Male: (A) carapace; ( B ) head; (C) telson; (D) a 
middle flagellomere of second antenna; (E) clasper. Female: (F) head; (G) telson. For clarity some growth lines of 
the carapace are incompletely shown anterior to umbo. Scale bars 1 mm. 
