130 
Records of the Australian Museum (2014) Vol. 66 
Kensakia australis sp. nov. 
Figs 13, 14; Plate ID 
Type material. Holotype adult male, length 0.55 mm, 
P81210. allotype adult female, length 0.62 mm, P81211. 
Paratype specimens P81212 (10 $$, 5 SS) deposited 
at AM, Sydney. Additional paratypes deposited at NHM, 
London. All collected from a brown seaweed, Zonaria sp., 
sublittoral fringe, Point Vernon, Hervey Bay, Queensland 
(25°15'S 152°47'E), V. A. Harris 1997. 
Diagnosis. Labrum with medial pad of minute setules plus 
four or five lateral striations (ridge-plates absent); female 
rostrum broad (W/R = 4.1); females carry eight eggs; male 
antennule with transverse tunnel-like thickening of cuticle 
on ventral side of segment 4 (Fig. 13E), distal coupling 
denticle very small (3-5 pm), dactylus long (= length of 
segment 3+4), hooked distally; ventrolateral band on ventral 
side of cephalosome with net-like markings; very few dorsal 
sensilla; no setae lateral to female genital opening; male 
rostrum V-shaped ventrally; a and (3 setae on male caudal 
ramus short QA width of ramus); ventral setules on male anal 
segment; dorsal setae on female P5 not pinnate. 
Biometric data. Females (N = 25): maximum length (L m ax) 
mean 0.615 mm, range 0.58-0.65 mm, body length (L ur s) 
mean 0.58, range 0.56-0.61 mm; cephalosome width (W) 
mean 0.37 mm; rostrum (R) width 0.09 mm; genital double¬ 
somite width 0.186 mm, length 0.145 mm; caudal ramus 
maximum width 0.05 mm, length 0.135 mm, 
Ratios: L U rsAV 1.57, LmaxAV 1.66; W/R 4.1; genital 
double-somite w/1 1.27, arch 55% of length; caudal ramus 
22% of Lurs, 1/w 2.6, Hicks’ index for a 88%, for |3 76%, 
apex angle of ramus 42°. 
Males (N = 23): maximum length (L m ax) mean 0.55 mm, 
range 0.55-0.58 mm, body length (L U rs) mean 0.51, range 
0.49-0.64 mm; cephalosome width (W) mean 0.34 mm, 
range 0.31-0.37 mm, length 0.32 mm; rostrum length 0.045 
mm; caudal ramus width 0.04, length 0.05 mm; antennule 
(fully extended) 0.145 mm; spermatophore 0.078 x 0.02 mm. 
Ratios: L U rs/W 1.5, L m ax/W 1.6; cephalosome 58% of 
Lmax; caudal ramus 1/w 1.25; antennule 26% of body length 
Lurs, segments 3+4 41%, dactylus 43%, aesthetasc 70% of 
antennule length; spermatophore 14% of L U rs- 
Description. Adult females (Fig. 13A; Plate ID, p. 163): 
colour pale yellow or colourless, mid-dorsal area of 
cephalosome, metasome and genital double-somite dark 
blue-purple, caudal rami and P5s not coloured. Cephalosome 
semicircular, rostrum broad, not prominent, dorsal pits on 
cephalosome, metasome, genital double-somite and P5 
exopod small (3-5 pm), very few dorsal sensilla. Hyaline 
border clear, 6-7 pm wide. Ducts of marginal glands open 
dorsally. On ventral side of cephalosome there is a broad 
lateral band of net-like markings about 30 pm wide that 
narrows posteriorly (ventrolateral band, Fig. 13J) and a 
peripheral band of vacuous cells (seen from ventral side Fig. 
13H). Some specimens have reticulate markings on ventral 
surface of the rostrum. Labrum (Fig. 14J) with pad of minute 
hair-like setules and a group of four or five setules laterally, 
but no ridge plates. Genital double-somite (Fig. 14C) 
narrow (50% of cephalosome width), lateral border with 
fine setules, small notch marks boundary between anterior 
and posterior lobes, posterior lobe pointed posteriorly, arch 
deep, no anterolateral ridges (rugosities) present. Sternal 
sclerite of metasome segment 4 with fimbriate posterior 
border, genital opening narrow (35 pm), no seta at lateral 
comer of opening. Caudal ramus (Figs 13D) trapezoid (sides 
slightly divergent), maximum width 2 A down ramus, lateral 
and medial edges without setules, dorsal surface with net-like 
pattern, a and (3 setae close, terminal setae T1 and T4 plain, 
very small, setae T2 and T3 absent, posterior border with 
very short, fine setules. Structure and setation of mouthparts 
and ambulatory limbs typical of family. Antenna basis with 
triangular setules along anterior edge but no setules on lateral 
surface (Fig. 14B), exopod with five plumulose setae and 
one plain spinous seta, fine border setules on segment 1 of 
endopod, segment 2 with three lateral setae, end segment of 
geniculate setae plain, long thin comb-like claw (> % length 
of endopod segment 2). Mandible, maxillule and maxilla as 
shown in Figs 14G, I and K respectively, maxilliped (Fig. 
14L) basis with fimbriate border but no rows of small lateral 
setules. PI (Fig. 13C) with coxal seta, inconspicuous small 
patch of denticulate pegs at lateral end of fimbriate crescent. 
Sermlate spinous seta on segment 2 of P3 endopod (Fig. 
14E) shorter than endopod (0.8:1), large serrate spinous 
seta on segment 3 much longer than endopod (1.5:1). P4 
endopod with sermlate spinous seta on segment 2 and 3 (Fig. 
14D). Exopod of P5 lanceolate, without ventral expansion, 
dorsal surface pitted, apical end of ventral falciform ridge 
with concave notch (Fig. 14A), border setules short, two 
prominent dorsal setae and two apical setae. P5s extend 
beyond genital double-somite and caudal rami but do not 
touch posteriorly. Females carry eight eggs. 
Adult males (Fig. 13B). Colour similar to female 
except that the blue-purple dorsal area does not extend 
beyond metasome segment 2. Cephalosome truncated 
with sloping, rounded shoulders, lateral angle of antennule 
socket prominent. Rostrum narrow, keeled and Y-shaped 
in ventral view, width Vs of length (Fig. 14M). Dorsal pits, 
hyaline border, vacuolated cells, reticulate ventral band and 
labmm as for female. Caudal rami (Fig. 14H) rectangular, 
slightly longer than wide (1.2:1), dorsal surface with net-like 
markings, a and (3 setae short (< ’A width of ramus). Setae 
Tl, T2 and T4 very short and small (T2 and T4 lost on 
many specimens), T3 absent. Posterior border with very 
short setules. Small group of striations (5 or 6) on ventral 
side of anal segment at the posterolateral comer (Fig. 14H). 
Antennule (Fig. 13F) with pinnate seta on segment 1, distal 
coupling denticle on segment 4 small (3-5 pm) bicuspid, 
close to bmsh-pad, aesthetasc almost as long as segment 
3+4 + dactylus with two characteristic constrictions, dactylus 
equals length of segment 3+4, hooked at tip (Fig. 13F, G). A 
tunnel like indentation of the ventral cuticle is found on the 
ventral side of segment 4 just proximal to the sensory lobe 
carrying aesthetasc (Fig. 13E, “tunnel”). Limbs as for female 
except that P2 has only two terminal setae on the endopod. 
All setae on P4 endopod plumose. P5 exopod trapezoid, 
lateral seta with row of 12-15 ventral setules and of different 
shape to terminal setae (Fig. 14F). Spermatophore very small. 
Etymology. The first species belonging to Kensakia recorded 
from Australia. 
