Pillai: Serpulid polychaetes from the Australian Kimberleys 
99 
Diagnosis. Operculum absent or present; when present, 
occurs in position of second radiole; neither chitinous nor 
calcareous; peduncle pinnulate. Inter-radiolar membranes 
present. Thoracic membranes present; apron present. Thorax 
consists of 7 chaetigers; special collar chaetae simple, i.e., 
devoid of fin-shaped basal part; sickle-shaped chaetae 
present in posterior thoracic chaetigers; thoracic uncini 
rasp-shaped, their most anterior tooth simple; abdominal 
chaetae geniculate. 
Remarks. Hartmann-Schroder (1996: 573) adopts the 
subfamily Protulinae Uchida, 1978. According to Bianchi 
(1981), however, the distinction between Protula and 
Apomatus based only on the presence or absence of an 
operculum is apparently unjustified, and there is a need of 
a world revision of Protula (= Apomatus ). As stated also 
by ten Hove (1984), the genera Apomatus and Protula “are 
phylogenetically ill-defined.” The difficulties in distinguishing 
between the two genera on the basis of criteria usually 
employed by taxonomists are again brought out by ten Hove 
& Pantus (1985), who deal with them as an Apomatus/Protula 
“complex”. They also conclude that, in order to avoid further 
confusion, and until there is a full revision, one would have 
to abide by “the traditional use of Apomatus for operculate 
specimens, Protula for non-operculate specimens”. 
Although, in later studies, Ben-Eliahu & Fiege (1996: 
27) provide a key to distinguish between species of Protis, 
Apomatus and Protula from the Levant Basin, Kupriyanova 
& Jirkov (1997:222) consider Apomatus and Protula to be 
synonymous. They define the genus Protula (including 
Apomatus Philippi, 1844) as possessing 7 thoracic chaetigers, 
an operculum, when present, that is vesicular and occurring 
in the position of the second branchial radiole, an apron, 
“simple limbate” collar chaetae, sickle-shaped chaetae in 
the thorax, rasp-shaped uncini, and abdominal neurochaetae 
with dentate or sickle-shaped blades. They also describe 
Protula globifera (Theel, 1876), a new combination, and as 
a synonym of Apomatus globifer Levinsen, 1887. 
However, it is evident that other characters need to be 
considered in order to resolve their taxonomy. Firstly, the 
operculum in Apomatus occurs in the position first radiole, 
whereas, when present, it is in the second in Protula. 
Furthermore, although Protula possesses a pinnulate 
opercular peduncle as in the Filograninae, it differs from 
them in two additional characters, viz., in possessing a 
whorled radiolar arrangement and inter-radiolar membranes. 
According to Kupriyanova & Jirkov (1997), the type 
species of the genus Protula , namely, P. tubularia (Montagu, 
1803), possesses the following characters: branchial radioles 
varying in number from 15-50 pairs; a wide post thoracic 
ventral apron; simple collar chaetae; Apomatus- chaetae (= 
sickle-shaped chaetae in present paper) in posterior thoracic 
chaetigers; short anterior abdominal chaetae, distally curved 
and limbate (figure 10 F shows their geniculate bend), and 
rasp-shaped thoracic uncini, their most anterior tooth “long, 
simple not bifurcate.” 
Furthermore, differences between two species of Protula, 
namely, Protula bispiralis and P. tubularia are as follows: 
presence, in the former, of a central axis on which the 
radioles are spirally arranged in 3-10 whorls, in contrast 
with the latter in which the arrangement is semi-circular. 
This difference has been well described and illustrated by 
Day (1967: 818-820, figs 37.7k-n, 38.7o-r). 
The present paper follows ten Hove (1994) who, based 
on the literature, states that the tropical Indo-West Pacific 
records can be roughly brought together under two taxa.”One 
of them is Protula bispiralis with 3-8 whorls of spirally 
arranged branchial radioles and a tube diameter of up to 
two centimeters. The second is Protulopsis nigranucha 
(Fischli, 1900) which has “a semicircular arrangement of 
its radioles (at most in a 3 A spire), and with a tube of up to a 
few millimetres in diameter.” 
It is evident that ontogenetic studies relating to the 
following characters would be useful in the revision of the 
genus: the presence or absence of spirally arranged radioles 
and maximum number of spirals in relation to size, presence 
or absence of an apron, and whether the latter is present in 
juveniles and lost in adults. 
Protula bispiralis (Savigny, 1820) 
Serpula bispiralis Savigny, 1820: Paris, (3)21: 325-482. 
Serpula bispiralis .—ten Hove, 1994: 107-116; Day, 1967 
(2): 459-878; Straughan, 1967a: 251. 
Protula magnifica. —Straughan, 1967b: 41-42. 
Material examined. Kimberleys, Western Australia: 1 specimen, AM 
W202933, Rob Roy Reef, 14°26'S 124°52’E, 28 m, 4 Jul. 1988, st 49. 2 
specimens, AM W21439, Lafontane Island, 14°10'S 125°47'E, 15 m, 9 Jul. 
1988, st 68. 1 specimen, AM W21424, southwest corner of Lucas Island, 
15°13'S 124°31'E, 30 m, 24 Jul. 1988, st 101.1 specimen without tube, AM 
W21429, south side of Long Reef, 14°01’S 125°44'E, 20 m, 18 Jul. 1988, 
st 60; a total of 5 specimens, all coll. RA. Hutchings. 
Description 
Measurements. Maximum external diameters of two largest 
tubes, respectively: 13.0 mm and 12.6 mm, their thicknesses, 
1.5 mm and 1.3 mm, total lengths of two worms from AM 
W21439: 80.0 mm and 75.0 mm; their thoracic widths of 
9.5 mm and 8.6 mm, respectively. Abdominal segments in 
two larger specimens number 155 and 159, with capillaries 
occurring from about 81st to 109th and 81st segments, 
respectively, until about 4 segments from their posterior ends. 
Remarks. For a good species description, see Day (1967: 
818). Accordingly, it attains very large sizes, up to a length 
of 180.0 mm, and there may be up to 10 whorls of radioles 
on each side arranged along a central axis, united for a third 
of their length by a web (= inter-radiolar membranes). The 
largest specimen in the Kimberleys collection is less than 
half that size; it has 4 radiolar whorls on each side. However, 
NHM collection 1905 BMNH 1924.6.13.18 la contains very 
large specimen from Cargados Carajos, NE of Mauritius, 
Indian Ocean, collected by J.S. Gardiner, and identified as P. 
bispiralis by ten Hove. Although the worm is contracted in 
alcohol, and the radioles difficult to measure, the total length 
of the worm is well over 150.0 mm; its thorax is 60.0 mm 
long and 25.0 mm wide; its abdomen 05.0 mm long and its 
maximum width of 20.0 mm; and nine radiolar whorls could 
be counted on each side. A specimen from South Africa, in 
NHM collection BMNH 1936.10.16.312, also has 9 whorls 
on each side. 
The thoracic uncinal tori are in P. bispiralis apparently lost 
as the worms grow older. A similar situation also apparently 
prevails in P. tubularia from the Mediterranean, in which, 
according to Fauvel (1927: 381), their presence is not 
constant, occurring most frequently in smaller individuals 
