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Records of the Australian Museum (2009) Vol. 61 
Remarks. The above material of S. paumotanus (Chamber¬ 
lin, 1919) from the Solomon Islands were identified by 
Gibbs (1971: 203-204) as S. giganteus (Pallas, 1766). 
Apparently, Gibbs’s paper was published before Hove’s 
paper mentioned below became available. 
Ten Hove (1970:14) suggested that two subspecies could 
be distinguished under the genus Spirobranchus, namely, 
S. giganteus giganteus (Pallas, 1766) from the western 
Atlantic and S. giganteus corniculatus (Grube, 1862), new 
combination, from the Indo-West Pacific. Following further 
investigations, ten Hove (1994: 112-113) referred the S. 
giganteus corniculatus- complex to the S. corniculatus- 
complex, noting that the opercular plate is egg-shaped in the 
latter. As seen from the description of S. corniculatus (Grube, 
1862) earlier in this account (Figs 38A-D, 39A-D,I,J), the 
opercular plate is indeed conspicuously wider anteriorly than 
posteriorly, and its outline is more or less like a longitudinal 
section of an egg or a pear. 
In contrast, that of S. paumotanus is circular (Figs 
54B-F, 55A-D,H,J), as it is in species such as S. tetraceros 
(Schmarda, 1861), ( vide ten Hove, 1970: 6, and Figs 44C 
and 45G-I), as also in S. gardineri Pixell, 1913 (ten Hove: 
1994: 113) and other species of Spirobranchus described 
in this paper. There are, however, also other differences 
between S. paumotanus and S. corniculatus with regard 
to the operculum. Each dorsolateral horn in the former is 
unbranched, anteroventrally curved, pointed, and has a 
characteristic posterolateral groove covered by a brownish 
chitinous layer (Figs 54B-E, 55A-D). In contrast, each 
dorsolateral horn in S. corniculatus usually ends in a pair 
of short pointed process, while also bearing a group of 
short processes dorsally and a short dorsal curved spine 
beyond the latter and lack the characteristic groove covered 
by a brownish chitinous layer (Figs 39D,I-J; 40A-C). 
The ventral horn in S. paumotanus is also characteristic, 
being the highest of the three and projects conspicuously, 
anteroventrally, and then curves anterodorsally. It ends in 
two main outwardly curved branches, which may, in turn, be 
dichotomously branched at its tip once or twice to give rise to 
short outwardly curved processes (Fig. 54B-F). In contrast, a 
ventromedian process is frequently absent in S. corniculatus 
(Figs 39A,B,D,I,J; 40C), sometimes being represented by 
a knob (Fig. 39C) or by an aberrant process (Fig. 40A,B). 
There are also differences with regard to tube colour 
and form, maximum sizes attained, maximum numbers of 
radiolar whorls, and number of teeth in the thoracic uncini. 
The tube of S. paumotanus is white and initially bears only 
a low median longitudinal ridge, which abruptly develops 
one to few massive forwardly directed teeth, with the 
most anterior one often projecting conspicuously over the 
aperture. On the other hand, that of S. corniculatus ranges 
in colour from yellowish orange to bright orange and has a 
single, somewhat smooth, median longitudinal ridge, with 
fine transverse ridges on either side of it. It does not bear 
similar massive teeth, with one of them projecting over the 
aperture of its tube. The maximum total length attained 
by the worm in S. paumotanus is about 35.0 mm, with a 
thoracic width of 2.5 mm, as opposed to over 110.0 mm and 
10.0 mm, respectively, in S. corniculatus. A specimen of S. 
corniculatus from Male described later in this paper has a 
total length of 90.3 mm and 226 abdominal segments. On the 
other hand, the maximum number of abdominal segments 
in S. paumotanus is probably less than 100. The maximum 
number of radiolar spirals observed in S. paumotanus is 5 on 
each side. In comparison, four out of the five specimens of 
S. corniculatus from Kimberleys collection AM W202960, 
possess 7 spirals on each side, and the fifth 5. Again, 10 
radiolar spirals were counted in the very large specimen 
from Kimberleys collection AM W202958. There is also a 
significant difference with regard to the maximum number 
of teeth in the thoracic uncini. It is 12-14 in addition to the 
gouged process in S. paumotanus, whereas it is double that, 
22-24, in S. corniculatus. 
Morch (1863: 411, fig. 26) describes Pomatoceros 
bucephalus from Zamboanga, the Philippines, which is very 
similar to S. corniculatus (Grube, 1862). It is synonymized 
with the latter here, which has priority over the former. 
Gibbs (1969: 203) describes the habitat of S. giganteus as 
“embedded in Porites boulders (Gibbs, 1969: fig. 138) and 
encrusting on reef platform.” 
However, information concerning the habitat of the 
Komimbo Bay sample, BMNH 1970.855 (= S. paumotanus 
[Chamberlin, 1919] in the present account) is quite different 
and indeed quite interesting, since it is unusual for a 
Spirobranchus species. According to the label in the jar 
containing the above specimens collected on 19/08/65, the 
species lives “Under boulders in muddy silt.” The label also 
states “MTL-LWM, silt.” 
Spirobranchus pseudopolytremus n.sp. 
Fig. 56A-I 
Pomatoceros polytrema (Philippi, 1844).—Dew (1959: 42, 
fig. 15,16). 
Material examined. Holotype and paratype, BMNH 1959.10.10.39; 2 
specimens with only anterior parts of their tubes, one worm complete, the 
other incomplete posteriorly, Cronulla, New South Wales, 34°04'S 151 °09'E, 
identified by D. Straughan as Temporaria polytrema (Philippi, 1844), and 
presented by B. Dew. Worms in this collection not too well preserved, 
apparently having been dried up previously and re-introduced into alcohol. 
Description 
Measurements. Maximum external diameter of tube 5.2 
mm, including the lateral flanges; 3.6 mm, excluding flanges. 
Maximum height, including MLR, 5.0 mm. Total length of 
complete worm (holotype), 10.0 mm; width of thorax 1.5 
mm; length of operculum and peduncle 3.0 mm; diameter 
of opercular cap 1.7 mm; and length of abdomen 4.3 mm. 
Branchial crown with 15 radioles plus operculum on left and 
14 radioles on the right. In the second specimen (paratype) 
branchial crown has 18 radioles on each side, in addition to 
the operculum on the left. 
Tube. Wide anteriorly with a broad flange, abruptly narrows 
posteriorly (Fig. 56A,B); MLR low smooth, somewhat 
irregularly formed, ends anteriorly as a small low tooth 
over aperture. A row of irregularly formed foramina present 
on each side of MLR, at its base (Lig. 56B). An irregularly 
formed, low, narrow, LLR present on either side of the MLR. 
A row of irregularly formed foramina present on each side at 
the base of each LLR. Laint, smooth, anterolaterally directed 
ridges and grooves, and foramina, extend into sides of tube 
and lateral flanges (Lig. 56A,B). 
