Capa & Murray: Australian Megalomma sabellid polychaetes 
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Figure 5. Drawings to scale of radioles sections, at the base: (A) Megalomma 
phyllisae n.sp.; (B) M. interrupta n.sp.; (C) M. cf. miyukiae; (D) M. inflata n.sp.; (E) 
Megalomma sp. 1; (F) M. quadrioculatum; (G) M. trioculatum; ( H) M. lanigera; (/) 
M. suspiciens. Scale: 0.1 mm. 
the number of compound subdistal eyes also differs among 
specimens and is not related to the number of radioles (Table 
1, Fig. 9). All specimens share the same arrangement of a 
large radiolar eye on each of the dorsalmost radioles, but the 
small, similarly-sized subdistal radiolar eyes on a few lateral 
radioles can be absent entirely from some specimens. Dorsal 
lips bear long radiolar appendages that in some specimens 
reach the length of four thoracic chaetigers. In all specimens 
the peristomial collar has dorsal margins separated from the 
faecal groove, but in some specimens under the dissecting 
microscope, it is not clear whether pockets are absent or 
present, as some specimens exhibit low membranes as 
continuations of the dorsal margins of the collar which could 
be considered as vestigial pockets (according to Knight- 
Jones, 1997) (see Fig. 2M), a feature that is made very 
clear using scanning electron microscopy (see Fig. 7B,C). 
Also, the ventral lappets of the collar may be observed as 
overlapping or not, depending on whether they are erect or 
folded back. Specimens show variability in the size of the 
gap between ventral shields and thoracic tori, even within the 
same sample. In some specimens (e.g., holotype, paratypes, 
and AM W35498) shields and tori are separated by a wide 
gap, in others (e.g., AM W35496) they are separated only 
in posterior chaetigers, while in other specimens they are in 
contact in all chaetigers (e.g., AM W35497). 
After observing the variability within this morphospecies 
under both dissecting and compound microscopes, some 
specimens were selected from several different localities 
covering the species’ distribution and which also displayed 
the variability in the distribution of radiolar eyes, and 
these were studied under SEM. Thoracic and abdominal 
chaetae appear to be similar in shape, size and arrangement 
within their fascicles (Fig. 8B,C,F,G,J,M,N) but variability 
was observed among thoracic and abdominal uncini (Fig. 
8A,D,E,H,I,K,L,0). All specimens have similarly-sized 
teeth covering half the surface of the main fang in thoracic 
uncini, and a slightly greater surface area of abdominal 
uncini, but some specimens show relatively larger teeth 
(Fig. 7A,D,E,H,I,K) than others (Fig. 8L,0); however these 
differences do not seem to be correlated with the specimens’ 
differing geographical localities, as variability is observed 
among specimens from the same sample. Until further studies 
reveal if this is, in fact, a complex of species that coexist in 
the same habitats in the same localities, we consider this 
variability to be intraspecific. 
Colour pattern. The intensity of the pigmentation varies 
among the specimens and could be due to different methods 
or lengths of time of preservation. The specimens from 
Western Australia are more pigmented in general that those 
