bobthebirder's picture

Hydrozoan

Observed: 23rd November 2012 By: bobthebirderbobthebirder is knowledgeable about Invertebratesbobthebirder’s earned reputation in Invertebratesbobthebirder’s earned reputation in Invertebratesbobthebirder’s earned reputation in Invertebratesbobthebirder’s earned reputation in Invertebrates
DSCN4581
Description:

The long feathery part is, I believe, a large hydrozoan. Washed up on beach after a stormy night, see http://www.ispot.org.uk/node/306080 and http://www.dorsetwalks.com/reports/portland.htm

Identifications
Species interactions

No interactions present.

Comments

dejayM's picture

inclined to agree

Another post badly consigned to History without comment or agreement - despite over 320 reads.
I suspect you are right with Gymnangium montagui though is really is not easy from just one photo (I have agreed - it's LIKELY to be this!)
A western, not specially southern, species - see the NBN map
Epiphytic and lithophytic
Light yellow feathery fronds
Clearly just alternate and not precisely opposite - see Aglaophenia cupressina
Not the more common Halecium halecinum

The dorset Link has long since eroded but there are others -
http://www.habitas.org.uk/marinelife/species.asp?item=D5610
http://skaphandrus.com/en/marine-animals/species/Gymnangium%20montagui
http://www.european-marine-life.org/05/gymnangium-montagui.php
Oh, and yes to Hornwrack
Please add the tags Marine and ProjectM1
ðerek

JoC's picture

Just as an aside

while I was following up this id....

http://britishbryozoans.myspecies.info/content/beautiful-bryozoans-broug...

EDIT 3.3.17 I agree with Bob that this hydroid is probably one of the Aglaopheniidae.
Three British species look, in illustrations and photos, as if they have alternate branches directed to some extent forward. Lytocarpia myriophyllum, Aglaophenia tubulifer and Gymnangium montagui.
Ids of hydroids are easier if details of the individual hydranths are visible. However we don't have that here, so I have not agreed to a species.

Question: Can we assume that as the hydroid colony grows longer that the length of the side branches is limited? I couldn't find confirmation of that. It's not always clear to me if the various lengths given in the literature represent average or maximum values for our British waters.

Jo