''Radiospongilla sceptroides'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of freshwater sponge in the family

Spongillidae Spongilidae is a family of sponges that live in freshwater lakes and rivers. The following genera are recognized in the family: * '' Anheteromeyenia'' Schröder, 1927 * '' Corvoheteromeyenia'' Ezcurra de Drago, 1979 * '' Corvospongilla'' Annanda ...

. It was described as ''Spongilla sceptroides'' by Scottish-born Australian zoologist William A. Haswell in 1883, who discovered it growing on submerged wood in a pond in the vicinity of Brisbane. He described it as "Sponge green, encrusting, smooth, moderately elastic, not crumbling." He noted the spicules were

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

and pointed. It was found growing next to a yellowish freshwater sponge that he described as ''Spongilla botryoides''. A 1968 review of freshwater sponges failed to locate Haswell's original type specimen, so a new one was selected from the Merrika River near Womboyn in New South Wales. Material from New Zealand was described as ''Spongilla rotoitiensis'', but later regarded as ''R. sceptroides''. Yet more material originally classified as this species has been shown to be a different species, '' R. philippinensis''. A bright emerald green in colour and firm and rubbery in consistency, the sponge can spread laterally to some size, the new type specimen measured , growing on a flat rock. ''Radiospongilla sceptroides'' is widely distributed (although fragmented) along Australia's eastern coastline, from central Queensland through New South Wales and into Victoria, as well as New Zealand and New Caledonia. It has never been recorded west of the

Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughl ...

. Fossil material has also been recorded from Victoria. The population of

Thirlmere Lakes National Park The Thirlmere Lakes National Park is a protected national park that is located in the Macarthur region of New South Wales, in eastern Australia. The national park is situated approximately southwest of the Sydney central business district, a ...

is highly unusual in that the sponges there do not produce

gemmule Gemmules are internal buds found in sponges and are involved in asexual reproduction. It is an asexually reproduced mass of cells, that is capable of developing into a new organism i.e., an adult sponge. Role in asexual reproduction Asexual re ...

s, which suggests that the environment in the lakes is very stable. This has not been recorded elsewhere in Australia.

References

Spongillidae Sponges described in 1882 {{demosponge-stub