Dear Wamchum:

In the picture I can see a false branch, thus it is possible that you have a Cyanobacteria or Cyanophyta. I see also that the filament is multiseriate but I can see the true branches. Good luck with the determination. Eugenia

Dear Eugenia, thank you so much. I have another problem is I can not remove this species from the young thallus of sargassum horneri. this species can inhibit the growth of young S. horneri.

Hi Wanchun

I think that this is a species of the Rhodophyta.

You should look at the BANGIOPHYCEAE.

It might be species of the PORPHYRIDIALES (Stylonema sp.?) or BANGIALES (Bangia sp?).

Good luck

Razy

Can you possibly run a molecular approach towards resolving its taxonomic affilication ?

DNA extract> pcr ITS or 18S > sequence > phylogentic evaluation..

From morphology alone, I couldn't tell (the answers above show it's not obvious even to specialists). So why don't you try and extract a bit of DNA, make a PCR with rDNA (http://www.microbial-ecology.net/probebase/list.asp?list=primer), and then run it on the SILVA database (http://www.arb-silva.de/). Chances are you'll get a close match pointing to the phylogeny of your alga.

Dear Wanchun,

i also see a true branch and a multiseriate trichome in a thick sheath. But i never identify by photos. if you would send a rela material, i could look on the microscope.

Hello Wanchun. I agree with Eugenia and Razy- it can be Cyanobacteria or Bangiophyceae. In my opinion, the best way in this case - molecular identification.

I am also agree with those who saying its a cynobacteria or may be Anabena sp.

Can you please tell me the size or a picture with scale bar.

Hi Wanchun

From where are you observing this material?

I agree with one the colleagues, that told that this can represent a Bangiophyceae (Rhodophyta). In the Atlantic we have the taxon Bangia atropurpurea. Another possibility that you can verify is Erythrotrichia carne another Bangiophyceae. The possibility of barcode are really informative if possible. If possible you can send us dry material. We can provide this molecular evaluation for you.

Best regards

Hi Wanchun

It seems to me a cyanobacteria Lynbya,

Dear Wanchun Guan, like others, I also think that molecular identification is the most appropriate method to identify your species accurately. Morphological features alone are sometimes misleading because species morphological features can vary from region to region and ecological conditions as well.

Good luck.

M. S. Rahman.

It looks like a Bangia. If you want to send si-dried material we can sequence it and check it. Mariana C Oliveira ([email protected])

Dear Wanchun:

Bangia have uniseriate, unbranched filaments embedded in firm gelatinous matrix, becoming multiseriate by successive division of cells. The cells of Bangia show an axial, stellate chloroplast with prominent pyrenoid.

In the picture I can see a false branch and I can not (I forgotten the NOT in my previous comment) true branches. I thought in a Cyanophyta or Cyanobacteria due to the false branch, however I can not to identify a genus because Stigonema present true branches and the genera that I know with false branches are not multiseriate, additionally Stigonema species are found on moist rocks and in moist soil, some species are also aquatic, epiphytic on submerged objects such as rocks, wood or lake macrophytes, or entangled in algae.

In this point it would be necesary to take a better picture of the material for seeing if there is false branches and true branches, if there is chloroplast (stellate with central pyrenoid) or not. These morphological data will be sufficient for determined if the taxon is Bangia or a filamentous member of the Cyanobacteria. It is possible that you can determine it by molecular techniques but you can do that using morphological tools.

Kind regards. Eugenia

Dear Wanchun,

can you take a part of it and do some test such as iridian ink and starch test!

I think there are more than species in the showing photo.

It can be Halosiphon which is a cyanobacteria

Dear Wanchun:

Halosiphon Jaasund is a Phaeophycea, I think Kavitha was referring to Hapalosiphon Nägeli ex Bornet & Flahault which is a Cyanophyceae O. Nostocales. Kind regards. Eugenia

I am inclined to think this is Stylonema alsidii (Rhodophyta, Rhodellophytina)

Yep Jan

This was my first opinion but I was not sure.

thanks for all your help and suggestions. I attached the pic by camera and by MS. with 10*10. and this species was observed around coastal of East China sea.

Attached pic

In these last pictures we can see, above and in the left, filaments that that can be identified as Acrochaetium like species. In the right, bellow, I still think in Erytrotrichia or Bangia. As our colleague told, the presence and the kind of branches are diagnostic feature. So you need isolate the filaments and evaluate the complete morphology and cell structure. Are your material preserved in simple formalin? If yes, the structure of the chloroplasts can not be observed after some time...their morphology change.....things to think.... However, is important to remember that you are of the other side of the world in Relation of us in South America, for instance. So, is really important evaluate your local flora, maybe starting from these possibilities and eventually utilizing molecular tools to have a precise taxonomic determination.

Dear Wanchun:

Three of your new picture show filaments, uniseriate (not becoming multiseriate by longitudinal division of cells), aparently unbranched, cells show axial, stellate chloroplast with a central pyrenoid. You included arrows showing laterals, but I think this are not branches, they are probably germling (I am not sure, it would be necessary to analyse the material in detail). In my oppinion this taxon could be Erythrotrichia. Erythrotrichia carnea is a very common epiphyte on seaweeds. This taxon is a Bangiophycidae O. Erythropeltidales according to Van de Hoek et al. (1995: 69). The other picture is the same that the previous one, thus it is insufficient to progress in the analysis.

Kind regards. Eugenia

Dear Wanchun

Please search Nemacystus decipiens morphological characterrs. this species commonly occuring in Sargassum epiphytes

pls send this to Dr Thajuddin of Bharathidasan University who is an expert in symbiotic algae:

Email: [email protected]

I think this is a Hapalosiphon Nägeli ex Bornet & Flahault which is a Cyanophyceae O. Nostocales. But I not say to you ıt's species need some datas.. regards.