Pillai: Serpulid polychaetes from the Australian Kimberleys 
131 
well as a medial swelling. Its unmodified coronal spines 
end distally in swollen tips. On the other hand, based on 
Straughan’s study of 6 specimens (1967: 34, fig. 3H,I), the 
corona of H. trivesiculosus, consists of only 5 processes. The 
modified process is massive, trivesicular in cross-sectional 
appearance and elongated, while the 4 unmodified processes 
are like tiny appendages at the base of the latter, ending in 
minute pinhead-like swollen tips. 
Ten Hove’s studies and drawings referred to above 
include collections both identified and misidentified as 
H. tivesiculosus Straughan, 1967, as well as un-identified 
material from various localities. Those identified as H. 
tivesiculosus are, from Australia: Heron Islands (AMF, det. 
Straughan), and Lizard Island. Among misidentified ones: 
BMNH 1870.12.23.63, as Eupomatus albiceps (Grube, 
1870) from the Red Sea, Gulf of Suez, legit. J.K. Lord, 
separated by H. Zibrowius from Spirobranchus giganteus 
in 1970; Nat. Hist. Mus. LA, one incomplete specimen, as 
H. albiceps by Straughan, from Port Douglas, Qld, which, 
according to ten Hove’s notes is “with typical operculum” 
(of H. trivesiculosus). Non-type material identified as H. 
trivesiculosus consist of a loose dried up operculum from 
Heron Island in Nat.Hist.Mus. LA. The unidentified material 
determined as H. trivesiculosus are BMNH from Kunduchi 
Island, collected by Pillai, 28.08.1981 and ZMK, from 
the Java Strait. In general, they all agree with Straughan’s 
description of H. trivesiculosus summarized in the preceding 
paragraph. 
Characters relating to the tube of H. spiratubus, that 
distinguish the latter from both Fauvel’s species from French 
Polynesia and H. trivesiculosus from Queensland, are as 
follows: tube of H. spiratubus is spirally coiled, its coils 
bonded together; and possesses an umbilicus (see under 
description of tube and Figs 22A, 23A). Fauvel (1923: 49, 
fig. 7) describes that of the French Polynesian species as 
being loosely coiled: “tube blanchatre, faiblement bossele, 
sans ornementation speciale, est lachement enroule sur la 
coquille d’une Huitre perliere.” Tubes of many serpulids may 
be sinuous or loosely coiled. Tube of “H. albiceps ” from Sri 
Lanka, as well of the above collections studied by ten Hove, 
is quadrilateral to trapezoidal in cross-section and usually 
bears a pair of longitudinal ridges. 
Etymology. Named after the spirally coiled tube. 
Hydroides trihamulatus n.sp. 
Figs 24A-G, 25A-C, 26A-L 
Material examined. Kimberleys, Western Australia: 4 specimens, AM 
W21412, sand cay on Port George IV, 15°20'S 124°39E, 12 Jul. 1988, st26, 
of which 1 lacks part of its tube and posterior end of its abdomen; two lack 
their tubes and consist of anterior ends only; and one consists of radiolar 
crown of one side only. 5 specimens, AM W202944, sand cay on Port 
George IV, 15°20'S 124°39’E, 12 Jul. 1988, st 26; all coll, by PA. Hutchings. 
Juveniles. 2 specimens, AM W202944, sandy cay on Port George IV, 
15°20'S 124°39'E, 12 Jul. 1988, st 26; 1 specimen, AM W21469, south west 
comer of Lucas Island, Kimberleys, Western Australia, 15°13'S 124°31'E, 
30 m, 24 Jul. 1988, st 101. 1 loose radiolar crown from one side only plus 
operculum, AM W202939, sandy cay on Port George IV, 15°20’S 124°39'E, 
12 Jul. 1988, st 26.1 specimen, AM W202944, sandy cay on Port George IV, 
15°20’S 124°39E, 12 Jul. 1988, st 26 (table 14, no. 4). 1 specimen lacking 
tube, AM W202943, reef north west of Buffon Island, 14°55'S 124°48'E, 
12 Jul. 1988, st 26; all coll, by PA. Hutchings. 
Description 
Measurements. From AM W21412: largest tube diameter 
1.5 mm; thoracic width in three specimens 1.0 mm; 
maximum; length of operculum and peduncle 3.7 mm; 
length of operculum only 0.9 mm. Maximum number 
of branchial radioles observed 10 per side. Number of 
abdominal segments could not be determined since worms 
are incomplete posteriorly; however, 25 could be counted 
in the available anterior part in one specimen. Total length 
of highly coiled worm from AM W202943 without its tube: 
9.9 mm; width of thorax 1.0 mm, length of operculum and 
peduncle 3.0 mm, length of operculum 1.3 mm, length of 
abdomen 5.3 mm, and number of abdominal segments about 
55. A smaller specimen 4.8 mm long has 51 abdominal 
segments, with capillaries commencing on about the 40th 
segment. 
Tube. White in juveniles, dull white in older specimens; 
squarish to trapezoidal in cross-section; possesses two 
longitudinal ridges with a comparatively wide longitudinal 
depression between them (Figs 24A,B, 26A-C), which may 
only be faintly developed (Fig. 24E). A granular overlay is 
present along certain areas (Fig. 24A,B,E); may be faint in 
some specimens. 
Worm. Operculum on either left or right side; light caramel 
coloured, its cuticle transparent. Number of coronal 
spines range from 11-15; number of infundibular lobes 
17 to 24. Coronal and infundibular spines show variations 
associated with ontogenesis. In infundibular spines of early 
juveniles (Fig. 24D,F), their tips are simple and pointed. 
Modified modified coronal spine becomes larger than the 
rest, develops a translucent medial swelling, and ends in 
a pair of blunt outwardly directed processes (Fig. 24C,D). 
Unmodified coronal spines: outwardly directed and devoid 
of basal spines. Infundibular spines may remain simple and 
pointed while coronal spines become swollen at their tips, 
foreshadowing the T-shaped tips of later stages, while the 
medial swelling and forked tips of the modified coronal spine 
become more prominent (Fig. 24F). In a later stage (Fig. 
24G), both infundibular and coronal spines are T-shaped; 
and medial and the two terminal processes of the modified 
coronal spine become even more prominent (Fig. 24G). 
The adult worm shown in specimen from AM W202943 
(Fig. 25A) has 9 radioles plus rudimentary operculum on 
left, and 8 plus operculum on right. The smaller specimen 
mentioned under measurements has 6 radioles per side. 
Although 11-15 coronal spines were counted in juveniles, 
only 10 are present in the present adult specimen, making 
their range in the present collection from 10-15; all devoid 
of a basal process. The medial process of modified coronal 
spine is a firm, beak-like process, curved towards the centre 
of the crown (Fig. 25 A-C). Both processes at the distal end 
of the modified coronal spine are fully developed, their tips 
pointed and laterally curved (Fig. 25 A-C). Infundibular radii 
number 19. While the tips of the unmodified coronal spines 
and the marginal infundibular processes are T-shaped or end 
in rounded tips in later juveniles, they are anchor-shaped 
and with pointed transparent laterally directed tips in adults 
(Fig. 25A-C). 
Chaetae. Bayonet-shaped special collar chaetae (26G-J) 
possess two main conical processes at the base of the blade 
Erratum. Types not designated, therefore name unavailable—see Murray et al., 2010. 
Murray, Hutchings & Pillai, 2010. Note on Hydroides malleolaspinus from the Kimberleys of Western Australia (Polychaeta: 
Serpulidae). Records of the Australian Museum 62(3): 393-394, doi:10.3853/j.0067-1975.62.2010.1564. [Editor—6 Dec. 2010] 
