Pillai: Serpulid polychaetes from the Australian Kimberleys 
139 
Figure 30. A-I, Serpula nudiradiata n.sp., fromholotype, AM W202942: (A-E) 
bayonet-shaped collar chaetae showing variations in the number of teeth and ser¬ 
rations at the base of the blade, as well as absence of an un-serrated notch; (F,H) 
thoracic uncini; (G) anterior abdominal uncini; (/) posterior abdominal uncini. 
conspicuously squarish boss, and a transverse row 
of small serrations, which precede the larger teeth 
on the boss (Figs 29L, 30A-E). 
Etymology. The specific name nudiradiata 
denotes one of the characters i.e., lack of 
tubercles along the radii of the operculum, which 
distinguishes it from certain other species, such 
as S. jukesii, that possess them. 
?Serpula species 
Fig. 31 A-I 
Material examined. Kimberleys, Western Australia, 1 
specimen with tube and rudimentary operculum only, AM 
W21414, south side of Slate Island, 15°32'S 124°24'E, lower 
intertidal, rocks, 9 Jul. 1988, st 5; coll. P.A. Hutchings. 
Description 
Measurements. Length of worm, excluding 
missing operculum, c. 15.0 mm; width of thorax 
1.0 mm; length of abdomen 8.6 mm. Number 
of abdominal segments about 73; but not clear 
where capillaries commence since they are mostly 
missing. 
Tube. Tube trapezoidal in cross-section and 
consists of a posterior attached part and an anterior 
unattached part (Fig. 31A,B); its unattached 
portion characterized by a series of peristomes; 
dorsomedially, peristomes are directed anteriorly 
(Fig. 31 A). Aperture of tube surrounded by a broad 
rounded anteriorly directed upper lip, separated by 
an indentation on each side from a ventrolateral lip; 
the latter two separated by a mid-ventral indentation 
(Fig. 3IB). The dorsal lip may be partially sub¬ 
divided into two by a faint indentation (Fig. 3IB). 
The trilabiate condition, and even the partially 
subdivided dorsal lip, may be seen in peristomes 
along the tube. 
Thoracic uncini saw-shaped, with 5 teeth in a single row, the 
3 posterior ones are considerably smaller than the 2 anterior 
to them (Fig. 30F,H). Anterior abdominal uncini smaller, with 
4 or 5 teeth in a single row, of which the posterior 3 or 4 are 
abruptly smaller than most anterior tooth and approximately 
equal size (Fig. 30G); posterior abdominal uncini rasp shaped 
(Fig. 301). Corresponding pairs of anterior abdominal uncinal 
tori separated dorsally by a very short gap; widest gap 
between first pair, then decreases quickly from second, very 
narrow from about 3rd to 9th; almost meet from about 10th to 
the 20th (Fig. 29J); then widens, with tori being comparatively 
close together in rest of abdomen. 
Remarks. Serpula nudiradiata differs from S. jukesii in 
several respects. It lacks tubercles along the opercular radii, 
and possesses a sharp constriction between its peduncle and 
the operculum, a bulbous swelling in the proximal part of 
operculum, and a pair of apertures for the thoracic glands 
on the ventral side of the thorax. Its bayonet-shaped special 
collar chaetae are also different from those of S. jukesii : 
they lack an unserrated notch, and possess 2-6 teeth on the 
Worm. Number of radioles 11 radioles plus rudimentary 
operculum on left; radioles missing on right, but base 
of opercular peduncle can be recognized. Light brown 
clusters of prostomial ocelli clusters present. Thorax has 7 
chaetigers; apron present. 
Chaetae. Special collar chaetae bayonet-shaped; either bear 
two conical to triangular teeth at the base of the blade, with 
a smaller tooth between them (Lig. 31D,E,G,H), or only two 
main teeth (Lig. 31C,D). Unserrated notch is moderately 
long, even in a newly formed chaeta from within fascicle 
(Lig. 31L,H); blade about 6 times as long as unserrated 
notch. Thoracic uncini: saw-shaped, with 7 teeth (Lig. 31H); 
anterior abdominal uncini similar, with 4 or 5 teeth (Lig. 311). 
Corresponding pairs of anterior abdominal tori almost meet 
along the mid-dorsal line of the abdomen. 
Remarks. Unfortunately, the operculum is missing and it 
not possible to decide which genus among the Serpulinae 
sensu stricto it belongs to. Spiraserpula Regenhardt can be 
eliminated because of the lack of internal tube structures 
