28 
Records of the Australian Museum (2016) Vol. 68 
Pipers Creek within Smugglers Cove Caravan Park, Wallis 
Lake, New South Wales, Australia, 32°11 , 58 ,, S 152°30'39"E, 
S. J. Keable & A. Murray, 30 April 2015. Bell diameter 35 
mm (AM G.18182) to 210 mm (AM G.18139). 
Comparative material of C. maremetens. QM G6645, 
3 paratypes (110-130 mm), Mud Island, Moreton Bay, 
Queensland, C. Wallace, 8 April 1972. 
Remarks. The Wallis Lake specimens appear to be closest 
to C. maremetens Gershwin, Zeidler & Davie, 2010, from 
Queensland (Figs 2I-L, 3D) (type locality, Lake Magellan, 
southwest of Caloundra, 26°49'42 M S 153 o 06'48.6 M E), with 
which they agree in most respects including exumbrella 
conformation, branching pattern of the oral tentacles and 
the numbers of rhopalia (19-21) (Gershwin et al ., 2010). 
The material from Wallis Lake (Fig. 2G) agrees with type 
material of C. maremetens (QM G6645; Fig. 2K), and most 
noticeably differs from the Lake Illawarra specimens (Fig. 
2C), in having alternating (i.e., non-opposing) rather than 
pinnate lateral branches along the length of the oral arms 
and lacking a distinct subequal bifurcation just distal to the 
midpoint of the primary arm. They differ, however, from 
both C. maremetens sensu stricto and C. ndrosia in the 
presence of numerous, large, conspicuous vesicles along 
the length of these arms (compare Fig. 2H and Fig. 2D [ C. 
ndrosia , Lake Illawarra] and Fig. 2L [ C. maremetens ]). The 
vesicles are variably leaf shaped (generally slightly broader 
in the distal half, maximum width approximately one-third 
length), and generally as wide as the lateral arm branches. 
The presence of the numerous large vesicles on the oral 
arms is the most significant distinction between the Wallis 
Lake specimens and C. maremetens sensu stricto, which has 
few or no vesicles. Gershwin et al. (2010), however, noted 
they could not adequately assess the significance of the 
presence or absence of vesicles in their material, whether a 
polymorphism or indicative of an additional unrecognized 
species. Just as Gershwin et al. (2010) observed no 
correlation between body size and presence of vesicles on 
the oral arms in C. maremetens , the vesicles in the Wallis 
Lake specimens are similarly numerous across the size range. 
Significantly, our Wallis Lake specimens also differ from 
the description of C. maremetens in the lappet shape and 
arrangement (Fig. 3C-D). Ocelli are present in the Wallis 
Lake specimens, absent in C. maremetens. The margin of 
the parameres in the Wallis Lake specimens are sinuous, 
resulting in 4-5 low, rounded lobes (Fig. 3C). In contrast, 
the lappets of C. maremetens are reported as square and 
deeply incised, with four per paramere (Gershwin et al ., 
2010). Close examination of paratypes of C. maremetens , 
however, revealed the squared, apparently deep incisions 
are bridged by transparent exumbrella membrane (Fig. 3D). 
Thus, instead of being deeply incised, the outline of the 
lappets of C. maremetens (at least in the paratypes examined) 
is actually essentially sinuous and indistinctly lobate, much 
like that of C. ndrosia. The lappets in the Wallis Lake 
material differ from C. maremetens in having a more strongly 
sinuous margin with more numerous lobes per paramere. 
The differences in lappet shape and vesicle complement in 
comparison to C. maremetens suggest that the Wallis Lake 
specimens may represent a separate, possibly undescribed 
species. Pending further study, however, we tentatively 
identify our material as C. cf. maremetens to highlight its 
similarity to C. maremetens. Cassiopea maremetens sensu 
stricto is presently known from Bentinck Island, Gulf of 
Carpentaria, Queensland (c. 17°03 , 34"S 139°29 , 09 M E) 
to Moreton Bay on the Queensland east coast (27°48'S 
153°24'E). Reports of C. andromeda from Southport, 
Queensland (27°58'S 153°25'E), just south of Moreton Bay, 
may also represent C. maremetens (Gershwin et al., 2010). 
The original collector of Cassiopea cf. maremetens from 
Wallis Lake first observed these jellyfish “in their hundreds” 
in Pipers Creek in 2009. The 2014 outbreak in the vicinity of 
Godwin Island (reported as “in large numbers within a small 
area”), documented here with specimens, was noticed on or 
near 2 August 2014 although specimens were not collected 
until 15 August 2014. Specimens of C. cf. maremetens were 
obtained again from the same location in Pipers Creek in 
September 2014. 
Subsequent fieldwork in Wallis Lake in April 2015 
confirmed the continued presence of C. cf. maremetens 
in Pipers Creek (Fig. 4B) and at a third locality within the 
lake adjacent to the shore at Mather Island (Fig. 4C). A 75 
m transect line was placed randomly along the shoreline in 
both these locations and Cassiopea within 1 m of the shore 
along this distance were counted. Five randomly selected 
individuals from each transect were also measured for bell 
diameter. At Pipers Creek, 30 individuals were present along 
the transect, the bell diameter of the individuals measured 
ranged from 120 to 210 mm (Fig. 4D) with a mean of 170 
mm. At Mather Island 24 individuals were present along 
the transect, those measured ranged in size from 40-70 
mm with a mean of 53 mm. Distribution of Cassiopea 
appeared patchy. Outside the transects, dense aggregations 
were observed (Fig. 4E,F) with up to 35 per square metre at 
Mather Island. A water temperature of 21,5°C and a salinity 
of 28.7 parts per thousand was recorded during the Mather 
Island transect and a salinity of 12.1 parts per thousand at 
Pipers Creek. Cassiopea were observed lying with the aboral 
surface resting on very soft sediment in depths of 10-100 cm. 
Discussion 
The impacts (both ecological and economic) and mechanisms 
behind invasions and population explosions of jellyfish have 
received considerable recent interest (Graham & Bayha, 
2007; Gershwin, 2013; Pitt & Lucas, 2014), influencing, for 
example, commercial fisheries, tourism and trophic structures. 
Species of Cassiopea feature in these reports as a globally 
invasive genus (see references cited above). 
Cassiopea has not previously been recorded from New 
South Wales. Pitt et al. (2006) note jellyfish as the most 
conspicuous animals in Lake Illawarra and indicate the 
three species most commonly seen as Catostylus mosaicus , 
Phyllorhizapunctata and Aurelia aurita but not Cassiopea. 
Similarly, other scyphozoans such as Catostylus mosaicus 
have been documented from Wallis Lake (Pitt & Kingsford, 
2000) but not Cassiopea. 
The samples reported here, therefore, represent a range 
extension for Cassiopea of approximately 600 km (Wallis 
Lake) to 900 km (Lake Illawarra) southward of the previous 
southern instance on the east Australian coast, Southport, 
Queensland. Given the lack of previous records, the 
apparently sudden appearance in large numbers is significant. 
We do not discount the role of normal environmental 
change in driving changes in species’ ranges. However, 
Cassiopea are not considered to have strong natural dispersal 
