Interesting to study the systematics of algae in general, especialy in respect to the changing phylogeny of algae as genomics (phylogeny based on nuclear-encoded Small Subunit Ribosomal RNA sequencing, see Schlegel*, 1994) is beginning to be applied to the phylogenetic tree for eukaryotic algae. The Phylum
Rhodophyta contains between 5000 and 6000 different species, deending on whose key you're using or which approach to the phylogenomics you take. This is actually a very interesting topic, worth a discussion in depth on a spearate thread in The Think Tank, especially if you consider that algae as a whole are not monophyletic, rather, the organisms we call algae developed at several different times with several different hypothetical ancestors and environmental beginnings, rather than a single ancestor, but I digress...
Getting back on target, identification with better than gessing accuracy of what this is will prolly require microscopic evalution, as there are several micro- and macroalgal genera that appear as this does when young or depending on whether the specimen in question is in its sporophyte or gametophyte stage of reproduction (and there are two morphological forms of these red algae in the sporophyte stage... ...I told you this might be a guessing game...), but almost all have the same resolution, which I'll mention in a moment.
My initial impression of the photos makes me think it is a
Gelidiopsis spp,
probably
G. scoparia. It is a tough, wiry seaweed with rounded or flattened thalli of 0.6mm to 1mm in diameter. The thalli often become wider and more flattened where branching occurs. The height varies from 2 to 8 cm depending on local conditions. This seaweed is dark brownish red in color and grows in intertidal habitats along rocky coastlines, native to most of the Indo-Pacific. Commonly called Red Wire Algae. It may be the related C
oelothrix, which has a more bluish red coloration, or possibly its a small version of
Pterocladia, which as it matures takes on a more fern-like thallus, or a
Gelidium spp, which has a more flattened blade-like thallus. If it begins to develop into small, soft little cottonballs of turfs, it is most likely
Ceramium or
Centroceras, but the thallus of
Centroceras will be banded upon microscopic examination. If this were very new (like less than a few weeks), it could be startups of
Gracillaria, especially if the area in question is a very
high flow area, but it will quickly begin to take on a macroalgal appearance with a thick fleshy thallus, and I do not think the pix reflect this attribute. One other possibility would be the sporophyte stage of
Asparagopsis, [/i]and although in aquaria with good water conditiions may have slow-growing colonies, it usually will be seen as a brushy soft thallus which appears as cotton candy tufts across the tank once established.
All these red algae, with the exception of
Gelidopsis will appear as a softer bush-like specimen(s), and all are usually quite palitable to Surgeonfishes (Tangs),
Siganus spp,
Diadema spp and a few other spp of
sea urchins, and some spp of hermit crabs and sea hares, although the wire algae may not be consumed by the crabs and sea hares. Usually, a good sized tang or Foxface is the resulution, or the presence of a Diadema sea urchin will resolve the issue. The presence of red algae is usually an indication that the tank has good water parameters, so this actually is not a bd thing, but if you don't want to have to depend on top-down herb8vory, harvest as much as possible, and either dispose of it responsibly (this does not mean flush it down the toilet...) or grow it in your refugium and harvest it to your mulch pile in the yard to export phospohates and nitrates.
Without using a microscope or having a specimen in front of me, I'd choose a
Gelidiopsis spp as your most likely candidate, but it could be any one of a number of the following genera that all start out as your photos show:
- Acanthropeltis
- Acropeltis
- Beckerella
- Gelidella
- Gelidium
- Pterocladia
- Porphyroglossum (these mature to specimens with wide blades, -glossum = Gr. tongue
- Ptilophora
- Suhria
- Yatabella
All of the above are genera of the
Gelidiales red algae and are related to the
Gracilariales
Much to consider, if you could spread out a specimen on some blotter papte and take about a 40x photograph it will help tremendously, especially with a specimen that is about 5 or 6 months old. You might check out some of the resources on the net for photographs and see what matches your specime the closest.
HTH
*
Schlegal, M. 1994. "Molecular Phylogeny of Eucaryotes," Trends in Ecology and Evolution 9:330-335.
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