Sea Anemones are invertebrates, meaning they lack a backbone, which animals like humans have.
95% of all animals are invertebrates, most of which are insects. The anemones are seen as fairly primitive, and are classed in the Phylum Cnidaria, which also includes corals and jellyfish. The common feature between these animals is that they all posses cnidae, or nematocysts. These are stinging cells which fire when stimulated, and send a tubule with spines on it, and may also involve toxins.
Anemones are basically a "hollow gut", where they have a single body cavity which serves as a stomach, lung, intestine and circulatory system. This cavity has one opening at the top, which is the mouth, and this is surrounded by the tentacles. At the base of the anemone is the pedal disc, which is used to attach the anemone to the substrate.
A previous study showed that of the Anthozoa (which include corals, anemones and zoanthids) anemones were the least known group. Australia has never had a full-time specialist working on anemones, and we predict that there are many new species waiting to be discovered. At the start of the project, it was estimated that approx 100 species of anemone were found within Australia's boundaries. We hope that this project will find more species.
One of the best known groups of sea anemones are the anemone-fish host anemones. These are generally large, colourful anemones that live on reefs and have a unique symbiosis with a group of fish, called the anemone-fish. An example of this was seen in the movie "Finding Nemo" where Nemo and his dad live within the tentacles of a host anemone, in this case Heteractis magnifica. Some specimens of this species have grown to a massive size, where their diameter is 1.5 metres! There are 10 species of anemone that are involved in this situation, and about 27 species of anemone-fish. Other organisms also use the anemone as a home, including other types of fish, and small crabs and shrimp.
However, these magnificent and picturesque anemones are a small sample what else is out there. Most anemones are tiny, no bigger than your thumbnail. Some live in the sand, burying their body, so that only the tentacles are visible. Some live attached to rocks, either in the surf zone on the coast, or attached to the bottom of rocks in a calm muddy bay. Others survive in deep sea environments, and there is a range of anemones that live and thrive in the Antarctic environment.
Part of my job involved going out into the field to actively search for anemones. So far I have investigated 37 sites, most in Queensland, but also a couple in Sydney, New South Wales and Gove in the Northern Territory. If anemones are found, I collect them and take them back to the laboratory. Laboratory work plays a vital part in this project; in-depth study of the nematocysts and internal structures is essential before species can be identified and a new species described. In the laboratory, anemones are kept in aquaria for observation where I take notes on the colour posture and reaction features of the living anemone. Once this is complete, I can do some closer anatomical studies under a dissecting microscope. Larger specimens are dissected to reveal features such as the nature of the marginal sphincter muscle and the arrangement of mesenteries within the gut of the anemone. For smaller specimens, however, histological study is necessary to examine these features. The final element of a species description includes the distribution and measurement of microscopic nematocysts from different tissues of the specimen.
Another part of this project involves my colleagues and I going to visit the museums around Australia and looking at the anemone specimens in their collections. This enables us to view anemones from locations that we may never visit ourselves, and the collections often date back to over 100 years ago! The museums are an important source as far as records for anemone distributions are concerned.
Deep Sea Anemone: (Stylobates n. sp.) - Genus of anemone which settles on a small shell, and can secrete its own shell-shaped carcinoecium. This new shell is completely covered by the anemone, and provides a new home for a hermit crab. These species are from very deep sea areas, the ones I am working on at the moment were collected from between 500-1000m deep! They were collected on a scientific survey of the deep sea area off the QLD coast, and were trawled up from the deep. The association of these animals is a form of symbiosis, in this instance the crab gets protection from potential predators, and a shell to live in. The anemone appears to get scraps of food from the messily-eating crabs, and perhaps the crab keeps the shell and anemone grounded, as it may easily float around the substrate and get damaged.
Swimming anemone: (Boloceroides mcmurrichi - This species was collected from the mud flats of Pallerenda, along with 3 other species. The swimming anemone is small, no bigger than a pinky fingernail, and has a reduced body size, but increased tentacle lengths in comparison. The anemone is able to pulse the tentacles and causes the anemone to rise into the water column, which most species of anemone cannot do. Once in the water column, it generally drifts along with the current, until it finds another suitable substrate to attach to. The anemone does prefer to be attached to something, but is known to actively swim. I collected three specimens of this Boloceroides mcmurrichi from Pallerenda last month; I found them attached to seagrass blades when I was out searching at low tide.
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