While visiting the Tessellated pavement last week, I also photographed a couple of the local inhabitants.
The first is a coralline algae, probably Corallina officinalis. This is very widely distributed species being found in places as far apart as Greenland and Australasia. While it may appear to be soft and plantlike, it is actually rather calcareous. The segments are coated in calcium carbonate which is produced within the cells. The growing tips have a higher concentration of calcium carbonate giving them a white appearance as can be seen in the photograph.
Another very conspicuous resident is a small seastar, Patriella vivipara which is considered an endangered species. The name vivipara alludes to the fact that this unusual seastar is viviparous. It broods it's young internally and releases them through the upper body wall (between the dorsal plates). I imagine this would increase the survival rate of the young compared to most other seastars which have a planktonic stage but the downside is the limited dispersal of the species. As a result their are only found at about ten sites in south-eastern Tasmania.
Edit: Apparently, while still in the brood cavity, larger juveniles can cannibalise the smaller ones.
Seastar - Patriella vivipara
Edit: As mentioned by Snail in the comments below, the small gastropod next to the seastar seems to be Siphonaria diemenensis (Van Diemen's Land Siphon Shell)
- Edgar J. E . 2000. Australian Marine Life - The Plants and Animals of Temperate Waters - Reed new Holland
- ~ 2003. Between Tasmanian Tidelines - A Field Guide - Tasmanian Marine Naturalists Association in association with the Tasmanian Museum and Art Gallery