Thursday, 7 August 2008

Life on the Pavement

..... the Tessellated Pavement

While visiting the Tessellated pavement last week, I also photographed a couple of the local inhabitants.

Corallina officinalis

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.

Coralline Algae - Corallina officinalis



Patriella vivipara

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)



References:
  • 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

4 comments:

  1. Lovely pics, as always.

    That Patiriella looks like a piece of orange peel! And is that a little Siphonaria limpet next to it?

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  2. Hi Mosura

    More great shots - you could easily mistake the seastar for an orange peel!!

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  3. Love both these photos. The Coralline is such a lovely heathery colour and so delicate and the Seastar looks to me just like some orange peel. We saw some fungus that looked like orange peel somewhere in Australia, again I can't remember where! Wish I'd taken notes now.

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  4. Thanks Snail, Adrian, & Jenny

    Funny that all three of you, prior to my publishing comments, suggested the seastar looks like orange peel.

    Yes snail I noticed the little shell. I thought it was Siphonaria diemenensis - I don't think there is anything to confuse it with in Tassie but I may be wrong. You would be the one to know. After all it takes a snail to know a snail :-)

    There is a British Orange Peel fungus as well - Aleuria aurantia - You'll have to keep an eye out for that one.

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