78 
G.L. Pesce, P. De Laurentiis, W.F. Humphreys 
MATERIAL AND METHODS 
Various plankton nets (mesh size 125 pm) were 
used to collect copepods from wells, bores, caves 
and anchialine pools on the Cape Range peninsula 
and its hinterland in northwestern Australia, as 
described fully in Pesce et al. (1996). 
Specimens, completely dissected, were mounted 
on cover slips in commercial polyvinyl- 
lactophenol. The figures were prepared using a 
camera lucida on a Leitz Laborlux D phase- 
contrast microscope. 
Holotype and paratypes of the new species, and 
material of H. spinifer, are deposited in the Western 
Australian Museum, Perth, Australia (WAM); one 
paratype was deposited in the Museo Civico di 
Storia Naturale, Verona (Italy). 
Terminology applied to body and appendages 
according to Huys and Boxshall (1991). 
Family Cyclopidae Burmeister, 1834 
Subfamily Halicyclopinae Kiefer, 1927 
Genus Halicyclops Norman, 1903 
Halicyclops lonvifurcatus sp. nov. 
Figures 1-11, 24 
Material Examined 
Holotype 
$ (WAM 248-94), Bundera Sinkhole (karst index 
number C-28), (BES 2470), Cape Range Peninsula, 
Western Australia, Australia, 22°25'S, 113°46'E, 6 
August 1993, W.F. Humphreys and R.D. Brooks. 
Paratypes 
Australia: Western Australia: 9 $, 1 juvenile 
(WAM 249-94 to 257-94 and 263-94), same data as 
holotype; 1 $ (BES 2476: WAM 258-94), same 
locality as BES 2470. 
Description 
Female (holotype) 
Body length 755 pm, body length range of 11 
paratypes 750-760 pm. Hyaline fringes of 
prosomites smooth. Genital double somite about as 
long as broad, expanded into two rounded lateral 
protuberances. Hyaline fringes of genital double 
somite and subsequent somites serrate, fourth 
urosomite with small denticles on the dorsal side 
of hyaline fringe. 
Caudal ramus long, 4.6 (holotype), 4.5-4.7 
(paratypes) times longer than broad; inner apical 
seta reduced to slender and naked seta, outermost 
apical seta about as long as lateral seta; dorsal seta 
as long as ramus; inner middle apical seta bearing 
4-5 spinules on distal part of basal half, terminal 
half irregularly plumose, outer middle apical seta 
with 5-6 spinules on distal half, irregularly 
plumose distally. 
Antennule 6-segmented, armed as in Figure 3. 
Antenna 3-segmented; basis with two inner distal 
plumose setae and one outer exopodal seta; middle 
segment with one inner seta; distal segment with 5 
inner and 7 apical setae (some plumose). 
Mandible reduced to coxa and gnathobase; palp 
consisting of two setae inserted on small 
protuberance. 
Maxillula: praecoxa bearing four setae and two 
spines on inner side and four stout spines distally; 
palp consisting of basis bearing three setae on inner 
margin, one proximal exopodal seta and 
endopodite with three distal setae. 
Maxilla as in Figure 2. Maxilliped 2-segmented; 
proximal segment bearing two setae, terminal 
segment with two inner modified setae and three 
long apical setae. 
Swimming legs 1-4 armament as follows (roman 
numerals denote spines, arabic numerals denote 
setae). 
coxa 
basis 
endopodite 
exopodite 
legl 
0-1 
1-1 
0—1 ^3—1 ;II—4 
I—1 ;I—1 ;III—5 
leg 2 
0-1 
1-0 
0—1 ;0—2;III—3 
I—1 ;I—1 ;I V—5 
leg 3 
0-1 
1-0 
0-l;0-2;III-3 
I-l;I-l;IV-5 
leg 4 
0-1 
1-0 
0—1 ;0—2;III—2 
I—1 ;I—1 ;III—5 
Leg 1, basis with spine at inner corner 
overreaching the posterior border of the 
endopodite segment 2. Legs 2-3 similar to each 
other; distal endopodite segment with proximal 
seta plumose basally and spinulose distally. Leg 4 
endopodite segment 3 longer than broad (1.48- 
1.57:1); inner apical spine slightly longer than 
segment and about 2 times longer than outer apical 
spine; inner setae spiniform, about equal in length, 
but only the proximal one basally plumose. 
Leg 5 exopodite about twice as longer as broad, 
and armed with one apical seta and three serrated 
spines. 
Male 
Unknown. 
Differential Diagnosis 
Several species of Halicyclops share with H. 
longifurcatus the lateral rounded protrusions on the 
genital double somite, the exopodite spine formula 
3.4.4.3, and the poorly developed hyaline fringe on 
the fourth urosomite (Lindberg 1957). 
From these species, as well as from other 
congeners, the new species may be distinguished 
easily by the remarkable length of caudal rami, 
unusual for species of the genus Halicyclops, and by 
the mandibular palp bearing two setae. 
