Pillai: Serpulid polychaetes from the Australian Kimberleys 
135 
Description 
Measurements. Maximum external diameter of tube 3.7 mm, 
width of thorax 1.2 mm, length of operculum and peduncle 5.7 
mm, length of operculum 2.1 mm, diameter of operculum 1.5 
mm, width of thorax 1.2 mm; worm incomplete posteriorly. 
Tube. White; coiled upon itself; possibly with a non-coiled 
part preceding the coiled part; mutually bonded coils; a 
conspicuous translucent granular overlay present (Fig. 27A) 
and two rounded longitudinal ridges. 
Worm. Holotype, operculum on right, rudimentary 
operculum on left (Fig. 27B); operculum bell-shaped, its 
proximal part rounded; number of radial lobes comparatively 
small, 17; broad, rounded, and with a thick translucent 
cuticle (Fig. 27B,C); tubercles absent; constriction between 
operculum and peduncle sharp. Number of radioles: 17 on 
each side, their pinnule-free tips not significantly different 
from pinnules (Fig. 27D). A large cluster of reddish 
prostomial ocelli present on each side. Abdomen: incomplete 
posteriorly. 
Chaetae. Bayonet-shaped special collar chaetae (Figs 27E-I, 
28A,B) bear two large acutely triangular to conical teeth at 
the base of blade; some bayonet-chaetae may have a smaller 
accessory tooth in between (Fig. 27F,G). Unserrated notch: 
short in older bayonet chaetae (Fig. 27E-I), moderately long 
in newly formed ones within collar fascicles (Fig. 28A). 
Thoracic and anterior abdominal uncini: saw-shaped, bear 4 
or 5 teeth (Figs 27J,K, 28D,E). Anterior abdominal uncinal 
tori: dorsolateral, with a wide gap separating corresponding 
pairs; gap about half the length of an uncinal torus in the 
region of the 6th to 10th abdominal segments (Fig. 28C). 
Remarks. The differences among Serpula amplilobata and 
the other species of Serpula dealt with in this paper, namely, 
S. jukesii Baird, 1865, S. nudiradiata n.sp., and S. watsoni 
Willey, 1905, are as follows, (a) Its tube is coiled upon itself 
and mutually bonded together, whereas those of S. jukesii, S. 
nudiradiata, and S. watsoni are not. (b), The operculum in S. 
amplilobata and S. watsoni is bell-shaped, whereas that of S. 
jukesii is funnel-shaped, (c) The operculum of S. amplilobata 
bears a few comparatively large radial lobes, whereas that 
of S. nudiradiata, S. jukesii and S. watsoni bears a relatively 
large number, (d) The opercular cuticle in S. amplilobata is 
thick and translucent, as seen in the grooves between and 
tips of opercular radii, whereas it is not so in S. nudiradiata 
and S. jukesii and S. watsoni. (e) The opercular radii of S. 
amplilobata and S. nudiradiata are devoid of tubercles, 
whereas those of S. jukesii and S. watsoni bear tubercles. (/) 
The proximal part of the operculum in S. amplilobata and 
S. watsoni is bulbous, whereas that of S. jukesii is tapering 
(as in other Serpula spp. with funnel-shaped opercula). (g) 
The constriction between the operculum and peduncle is 
sharp, in S. amplilobata and S. watsoni, whereas whereas it 
is not so in S jukesii. 
Etymology. The specific name amplilobata is derived from 
the Latin amplus = large and the Greek lobos = lobe, to 
describe the large rounded marginal lobes at the end of the 
opercular radii. They are few in number and much larger in 
size compared to those in species such as S. jukesii and S. 
nudiradiata. 
Serpula jukesii Baird, 1865 
Figs 27F-H, 28A-F 
Serpula jukesii Baird, 1865: 20, fig. 6. 
Serpula magna .—Straughan (1967a: 208, fig. 3c-h). 
ISerpula vermicularis .—Straughan (1967b: 30). 
Material examined. Kimberleys, Western Australia, 3 specimens, AM 
W21395, AM W29691 and AM W21394 from east side of Fenelon Island, 
14°07'S 125°43’E, 6 m, 18 Jul. 1988, st 64; coll, by P.A. Hutchings. 
Description 
Measurements. Tube of specimen in AM W21934 has 
the larger maximum external diameter of 9.0 mm and 
thic kn ess of 1.05 mm. Measurements of two larger worms, 
respectively, as follows, total lengths: 30.7 mm and 40.0 mm. 
Thoracic widths 5.7 mm and 4.7 mm. Lengths of operculum 
and peduncle 10.9 mm and 9.2 mm. Lengths of the opercula 
alone, 5.1 mm and 4.5 mm. Distal end of operculum is not 
perfectly circular; hence the larger and smaller diameters 
in the first specimen are 5.6 mm and 5.0 mm. Abdomen 
in one specimen is 19.8 mm long, has 175 segments with 
capillaries commencing from the 137th segment; 24.6 mm 
long in the second, and has 155 segments, with capillaries 
commencing from the 124th and 60 plus the operculum on 
the right; it is slightly higher in the second specimen, which 
has 62 radioles plus the operculum on the left and 56 plus 
the rudimentary operculum on the right. Pinnule-free tips 
are very short, slightly thicker than the pinnules. Prostomial 
ocelli and thoracic glands absent; an apron is present. In 
the first specimen, the abdominal segments number 175 
and capillaries start from segment 137; 155 segments in 
the second. 
Tube. Whitish to caramel coloured and thick; three faint 
longitudinal ridges present in some places; four closely formed 
peristomes present anteriorly in first specimen (Fig. 28F). 
Worm. Operculum funnel-shaped. As seen from measure¬ 
ments, its distal part is nearly circular, somewhat wider in a 
dorsoventral direction than laterally, its maximum diameter 
greater than length of funnel (Figs 28G, 29A). Number 
of radial lobes 75 in first specimen, 77 in second, bluntly 
triangular; cuticle thin, tubercles present along radii (Fig. 
29A). Proximal part of funnel elongated, gradually decreases 
in diameter to where it joins the peduncle; constriction 
between operculum and peduncle faintly recognizable (Figs. 
28G, 28A). First specimen has 58 radioles plus rudimentary 
operculum on right; 60 plus operculum on right; higher 
in second specimen, with 62 plus operculum on left, and 
56 plus rudimentary operculum on right. Pinnule-free 
tips of radioles: very short; slightly thicker than pinnules. 
Prostomial ocelli and thoracic glands: absent. Apron: present. 
Chaetae. Special collar chaetae bayonet shaped, and bear 2 
or 3 conical processes at base of blade (Fig. 29B); may be 
considerably abraded in older chaetae Fig. 29D). Unserrated 
notch, as seen in chaetae from deep within fascicle short to 
moderately long, about twice as long as teeth on boss (Fig. 
29B,C), long in older chaetae (Fig. 29D). Thoracic uncini: 
saw-shaped, with 5 teeth in single row (Fig. 29E); anterior 
abdominal uncini similar, with 4 or 5 teeth (Fig. 29F). 
